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    - CHEMICAL ENGINEERING (210 journals)
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CIVIL ENGINEERING (219 journals)                  1 2 | Last

Showing 1 - 200 of 219 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 20)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 3)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 3)
Advances in Civil Engineering     Open Access   (Followers: 43)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 34)
Agregat     Open Access   (Followers: 1)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 36)
Architectural Engineering     Open Access   (Followers: 5)
Architecture and Engineering     Open Access  
Architecture, Civil Engineering, Environment     Open Access   (Followers: 1)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 3)
Archives of Civil Engineering     Open Access   (Followers: 13)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 7)
Baltic Journal of Road and Bridge Engineering     Open Access   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 2)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 3)
Berkeley Planning Journal     Open Access   (Followers: 6)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 14)
Building & Management     Open Access   (Followers: 2)
Building and Environment     Hybrid Journal   (Followers: 16)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 15)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 6)
Canadian Journal of Civil Engineering     Hybrid Journal   (Followers: 14)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 10)
Cement and Concrete Composites     Hybrid Journal   (Followers: 20)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 3)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 8)
Civil and Environmental Engineering Reports     Open Access   (Followers: 8)
Civil and Environmental Research     Open Access   (Followers: 19)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 24)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 13)
Civil Engineering Dimension     Open Access   (Followers: 12)
Civil Engineering Infrastructures Journal     Open Access   (Followers: 1)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 291)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 37)
Concrete Research Letters     Open Access   (Followers: 7)
Construction Economics and Building     Open Access   (Followers: 4)
Construction Engineering     Open Access   (Followers: 11)
Construction Management and Economics     Hybrid Journal   (Followers: 21)
Constructive Approximation     Hybrid Journal  
Construindo     Open Access  
Curved and Layered Structures     Open Access   (Followers: 3)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 17)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Open Access   (Followers: 3)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 10)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 10)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 19)
Frontiers in Built Environment     Open Access   (Followers: 1)
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Gaceta Técnica     Open Access  
Geomaterials     Open Access   (Followers: 3)
Geosystem Engineering     Hybrid Journal   (Followers: 2)
Geotechnik     Hybrid Journal   (Followers: 4)
Géotechnique Letters     Hybrid Journal   (Followers: 8)
GISAP : Technical Sciences, Construction and Architecture     Open Access  
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indonesian Journal of Urban and Environmental Technology     Open Access  
Indoor and Built Environment     Hybrid Journal   (Followers: 3)
Infrastructure Asset Management     Hybrid Journal   (Followers: 3)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 36)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 17)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 2)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 15)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 10)
International Journal of Engineering and Geosciences     Open Access  
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 6)
International Journal of Protective Structures     Hybrid Journal   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 9)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Built Environment     Open Access   (Followers: 5)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 7)
International Journal Sustainable Construction & Design     Open Access   (Followers: 2)
Journal of Applied Research in Water and Wastewater     Open Access   (Followers: 1)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 13)
Journal of Building Engineering     Hybrid Journal   (Followers: 2)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering     Open Access   (Followers: 1)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 16)
Journal of Civil Engineering and Management     Open Access   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 10)
Journal of Civil Engineering Research     Open Access   (Followers: 8)
Journal of Civil Engineering, Science and Technology     Open Access   (Followers: 1)
Journal of Civil Society     Hybrid Journal   (Followers: 5)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites     Open Access   (Followers: 79)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 23)
Journal of Construction Engineering     Open Access   (Followers: 9)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 18)
Journal of Construction Engineering, Technology & Management     Full-text available via subscription   (Followers: 4)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 6)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 10)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 14)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 19)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 6)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 8)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 9)
Journal of Offshore Structure and Technology     Full-text available via subscription  
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 3)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 6)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 4)
Journal of Road and Traffic Engineering     Open Access  
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 36)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Structural Mechanics     Open Access   (Followers: 1)
Journal of Structures     Open Access   (Followers: 4)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 4)
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the Civil Engineering Forum     Open Access   (Followers: 2)
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 2)
Journal of Water and Environmental Nanotechnology     Open Access  
Journal of Water and Wastewater / Ab va Fazilab     Open Access  
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil     Open Access  
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Lithosphere     Open Access  
Materiales de Construcción     Open Access   (Followers: 1)
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 5)
Media Komunikasi Teknik Sipil     Open Access  
Media Teknik Sipil     Open Access  
Mokslas – Lietuvos ateitis / Science – Future of Lithuania     Open Access  
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 15)
npj Materials Degradation     Open Access  
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 9)
Periodica Polytechnica Civil Engineering     Open Access  
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 4)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 14)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 10)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 2)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Promet : Traffic &Transportation     Open Access  
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 5)
REDER : Revista de Estudios Latinoamericanos sobre Reducción del Riesgo de Desastres     Open Access  
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 6)
Resilience     Open Access   (Followers: 1)
Revista de Investigación     Open Access  
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Revista Sul-Americana de Engenharia Estrutural     Open Access  
Road Materials and Pavement Design     Hybrid Journal   (Followers: 11)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 5)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 61)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 5)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 11)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 8)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Mechanics of Engineering Constructions and Buildings     Open Access   (Followers: 1)
Structural Safety     Hybrid Journal   (Followers: 6)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 24)

        1 2 | Last

Journal Cover
Engineering Structures
Journal Prestige (SJR): 1.69
Citation Impact (citeScore): 3
Number of Followers: 13  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0141-0296
Published by Elsevier Homepage  [3157 journals]
  • Proposal and experimental validation of simplified strut-and-tie models on
           dapped-end beams
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Jaime Mata-Falcón, Luis Pallarés, Pedro F. Miguel
  • High-speed running maglev trains interacting with elastic transitional
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): You-Lin Xu, Zhi-Lu Wang, Guo-Qiang Li, Suwen Chen, Yeong-Bin Yang This paper presents a general framework for the dynamic analysis of high-speed maglev trains running on elastic transitional viaducts, a complicated problem that lacks an efficient analysis tool. Unlike the straight and circular tracks, both the curve radius (CR) and height difference (HD) between the outer and inner rails vary along the transitional track. To start, the motion of each vehicle of the train running over a transitional track is expressed by a set of trajectory coordinates, with their orientations given in the Euler angles as functions of the CR and HD. The elastic transitional viaduct is simulated by finite elements in the global coordinates. For the maglev trains, the electromagnet force-air gap model is used to account for the interaction and coupling effect between the moving vehicles and supporting viaduct. By applying the proposed framework to the Shanghai maglev line (SML), the dynamic responses of the maglev vehicles running on the transitional viaduct are studied and compared with those on the straight and circular viaducts. Moreover, the effects of transitional track length and cant deficiency on the coupled system are investigated. The results show that for vehicles running on the transitional track, the levitation forces and vehicle’s angular velocity are highly related to the rate of change of HD of the track. The length of the transitional viaduct affects significantly all the vehicle’s responses. The increase of deficient cant angle causes a sharp increase in the responses of the transitional viaduct in both the radial and rotational directions.
  • An uncertain computational model for random vibration analysis of subsea
           pipelines subjected to spatially varying ground motions
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Yahui Zhang, Yuyin Li, David Kennedy Based on a nonparametric modelling approach, this paper presents a random vibration analysis of a subsea pipeline subjected to spatially varying ground motions. The earthquake-induced ground motions are modelled as nonstationary random processes and their spatial variations are considered. The modelling uncertainties of the subsea pipeline are taken into account using a random matrix theory, while the unilateral contact relationship between the pipeline and seabed is also considered. Thus, an uncertain computational model for the subsea pipeline subjected to a random earthquake is established, and the corresponding solutions are calculated using Monte Carlo simulation (MCS). In order to highlight the contribution of the unilateral contact effect to random responses of pipelines, comparative studies are performed between the unilateral and permanent contact models. In numerical examples, the possible convergence problems in the present computational model are firstly studied to determine the optimal numbers of reduced modes and MCS samples. Then influences of the randomness in the earthquake and modelling uncertainties in the pipeline are investigated qualitatively through three representative cases. The different propagations of randomness and modelling uncertainties in the unilateral and permanent models are also examined and discussed. It is concluded that the randomness of the earthquake and modelling uncertainties of the pipeline have significant influences on the statistical characteristics of earthquake responses of the pipeline.
  • Superelastic NiTi SMA cables: Thermal-mechanical behavior, hysteretic
           modelling and seismic application
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Cheng Fang, Yue Zheng, Junbai Chen, Michael C.H. Yam, Wei Wang This paper reports a comprehensive study on the mechanical behavior, annealing (heat treatment) scheme, hysteretic modelling strategy, and potential seismic application of superelastic shape memory alloy (SMA) cables. The study commenced with the thermal-mechanical characterization of monofilament SMA wires, and in particular, the influence of annealing scheme on the mechanical and phase transformation characteristics of the material was revealed. A series of 7 × 7 SMA cable specimens were subsequently tested at room temperature under various cyclic loading protocols. It is observed, among other findings, that the SMA cables are able to reasonably “scale up” the satisfactory properties of the SMA wires, and the mechanical behavior of the SMA cables may be improved by annealing. Moderate annealing temperature and duration (i.e., 350–400 °C for 15 min) can generally increase the stiffness, energy dissipation, and form setting ability of the SMA cables considered in this study, whereas an overly high annealing temperature tends to compromise these characteristics. Following the experimental study, an effective numerical modelling approach is proposed which reliably captures the basic mechanical behavior of the SMA cables. A model bridge, where SMA cables are adopted as restrainers, is finally designed and analyzed to demonstrate the efficiency of the SMA components for seismic damage mitigation. The analysis result shows that the SMA-cable restrainers can effectively control the peak and residual displacements of the bridge girder, and make the bridge more resilient.
  • Axial capacity of steel tube-reinforced concrete stub columns
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Huan-Peng Hong, Huang Yuan, Lu Deng, Yu Bai The steel tube-reinforced concrete (ST-RC) column is an innovative composite structure that has been increasingly applied in high-rise buildings and bridge piers in China. This study aims to investigate the axial capacity of the ST-RC stub column by means of a modified superposition method. Primarily, the sectional confining force equilibrium was elaborated to explain the confinement mechanism of the ST-RC column under concentric compression, which involves the confining stress induced from the inner steel tube and secondary confining stress induced from the peripheral steel hoops. Thereafter, a modified method for predicting the axial capacity of the ST-RC column, considering the secondary confinement, was developed according to a stress and strain analysis. Thirdly, 41 published specimens were collected to verify the accuracy of the proposed method. It was demonstrated that the current method fitted strongly with the tests results and exhibited satisfactory adaptability. Finally, four other methods according to ACI 318, AIJ, EC 4, and CECS 188-2005 were verified in the same scenario. It was found that the current method exhibited superior correlation with the experimental results compared with conventional approaches. It will be favorable to obtain the viable axial capacity of the ST-RC column by using the presented solution.
  • Testing, numerical simulation and design of prestressed high strength
           steel arched trusses
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): S. Afshan, M. Theofanous, J. Wang, M. Gkantou, L. Gardner The structural behaviour of prestressed high strength steel arched trusses is studied in this paper through experimentation and numerical modelling. Four 11 m span prestressed arched trusses fabricated from S460 hot finished square hollow section members were loaded vertically to failure. Three of the tested trusses were prestressed to different levels by means of a 7-wire strand cable housed within the bottom chord, while the fourth truss contained no cable and served as a control specimen. Each truss was loaded at five points coinciding with joint locations along its span, and the recorded load-deformation responses at each loading point are presented. Inclusion and prestressing of the cable was shown to delay yielding of the bottom chord and enhance the load carrying capacity of the trusses, which ultimately failed by either in-plane or out-of-plane buckling of the top chord. For the tested trusses, around 40% increases in structural resistance were achieved through the addition of the cable, though the self-weight was increased by only approximately 3%. In parallel with the experimental programme, a finite element model was developed and validated against the test results. Upon successful replication of the experimentally observed structural response of the trusses, parametric studies were conducted to investigate the effect of key parameters such as prestress level, material grade and the top chord cross-section on the overall structural response. Based on both the experimental and numerical results, design recommendations in the form of simple design checks to be performed for such systems are provided.
  • Structural performance of state-of-the-art VectorBloc modular connector
           under axial loads
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Jothiarun Dhanapal, Hossein Ghaednia, Sreekanta Das, Jonathan Velocci The popularity of steel modular construction is on the rise. This paper presents a new and innovative modular steel construction which uses state-of-the-art cast-steel connectors and hollow structural steel members. Structural behavior of a typical corner connection of this modular construction to be used in an assisted living facility was studied when the connection is subject to axial tension and axial compression loads. The study was completed using both experimental method and a numerical method. Six full-scale specimens were built and tested under axial compression and axial tension. It was found that this innovative modular connection satisfactorily carries the design loads. Based on the parametric study completed using finite element method, two significant design improvements are recommended. The cast-steel connector can be made 20% lighter without compromising the strength needed to satisfy the design loads. The locations of the connecting screws can be adjusted to achieve a higher stiffness and load carrying capacity of the connection when subjected to axial tension. This paper presents the new modular construction method in brief, the test method and test results, development of finite element model, and parametric study.
  • Behaviour of concrete-filled corrugated steel tubes under axial
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Yuyin Wang, Ligui Yang, Hua Yang, Changyong Liu Concrete-filled tubular (CFT) structures are exposed to increasingly complex environments with ever-broadening applications. Anticorrosion maintenance is generally difficult and expensive for established structures exposed to the air. Due to the superior corrosion resistance and the high lateral stiffness of the corrugated steel pipe (CSP), concrete-filled corrugated steel tube (CFCST) is proposed which has the similar working mechanism with the tube confined concrete columns. Such innovative composite member has advantages such as free of maintenance, ease of construction, high load-bearing capacity, good ductility and strong interlocking effect between CSP and concrete. In order to verify the load bearing reliability of concrete-filled corrugated steel tube (CFCST), twenty-one short columns including twelve CFCSTs were tested under axial compression. It was found that the CFCST is a tube confined concrete member and behaves slightly better than tubed-concrete columns. The strain and stress of CSP are discussed in detail to clarify the confinement effect. As well, solid nonlinear finite element models (FEM) were established to investigate the influence of key factors including geometries of CSP and strength of materials, which were summarized in the confinement index. Based on early studies on steel tube confined concrete and the parameter analysis in this paper, a suitable design method to predict the ultimate axial compressive load capacity for CFCST columns is proposed in this paper.
  • Bayesian based nonlinear model updating using instantaneous
           characteristics of structural dynamic responses
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Yu Xin, Hong Hao, Jun Li, Zuo-Cai Wang, Hua-Ping Wan, Wei-Xin Ren This paper proposes a Bayesian based nonlinear model updating approach using the instantaneous amplitudes of the decomposed dynamic responses. Uncertainty quantification of the model updating results due to the measurement noise is conducted. The residual of the instantaneous amplitudes of the decomposed structural dynamic responses between the test structure and the analytical nonlinear model is used to construct the maximum likelihood function. Since nonlinear model parameters and simulated error variances of the instantaneous parameters are all unknown, the extended maximum likelihood estimation method is used to update these parameters. The uncertainty in the updated nonlinear model parameters can be evaluated by using the Cram-Rao lower bound theorem with the exact Fisher Information matrix. A numerical study on a three-storey building structure model under earthquake excitation is performed to verify the accuracy and performance of the proposed approach. An experimental verification on a high voltage switch structure under harmonic excitation is conducted to investigate the accuracy of using the proposed approach for nonlinear model updating. Both numerical and experimental results demonstrate that the proposed approach is reliable and accurate for nonlinear model updating, with the capacity of considering the uncertain noise effect in the measurements.
  • Impact force profile and failure classification of reinforced concrete
           bridge columns against vehicle impact
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Tin V. Do, Thong M. Pham, Hong Hao Numerical simulations are utilized in this study to define the impact force profile generated by vehicle collisions on reinforced concrete bridge columns (RCBCs) and classify the dynamic responses and failure of the columns under collision events. The results indicate that both the column properties (i.e. dimension of the cross-section and concrete strength) and initial conditions of vehicles (i.e. vehicle velocity, engine mass, and vehicle mass) play a crucial role in determining the impact force profile from the vehicle collision. A new vehicle impact force model is proposed for engineers to use in design of RCBCs under vehicle collisions in which the influence of shear failure of the column on impact force is considered. Based on the shear mechanism of RCBCs under impact events, the maximum dynamic shear capacity of a column is defined. Furthermore, the bending moment and shear force distributions, as well as the failure mode of RCBCs have been classified into two categories, i.e. flexural response and shear response governed failure with respect to the peak impact force (PIF) on the column. For the flexural response governed failure mode, flexural cracks at the intermediate sections are formed in the positive side of the column, while the diagonal shear or punching shear failure at the impact area together with negative flexural-shear cracks occur in the column if the shear failure mode dominant the column responses.Graphical abstractShear mechanism of the RCBC under vehicle impact.Graphical abstract for this article
  • Seismic behavior of composite beam connected to HSS column with large
           width-to-thickness ratio
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Mohammadreza Eslami, Hisashi Namba, Venkatesh Kodur, Mustafa Mahamid, Mohamed Ali Morovat This paper discusses out-of-plane deformations in a HSS (Hollow Structural Section) column connected to a composite beam. Width-to-thickness ratio of HSS column is an important parameter in the flexural deformation capacity of the connection. Beam web connection moment transfer efficiency in HSS column connection is poor and significantly less effective when compared to a connection with W-shape columns. This condition is more severe in the case of composite beam connected to thin walled HSS columns having large width-to-thickness ratio. In this research, the force flow pattern and ultimate flexural capacity of web connection are evaluated by considering main parameters affecting the out-of-plane deformations namely: width-to-thickness ratio of HSS column, height-to-thickness ratio of beam web, yield strength ratios of beam and column, height-to-width ratio of connection, slab strength, stud layout and geometry of weld access hole. Results from the analysis are utilized to illustrate the location of neutral axis and structural condition of web connection in different width-to-thickness ratios and different concrete slab strengths. Also, equations for evaluation of ultimate flexural capacity of web connection are derived; interaction curves of Moment-Axial force acting at the web are drawn. It was found that in the HSS column with large width-to-thickness ratio of 29, axial force subjected to the web connection results in significant reduction of web flexural capacity. Experimental tests showed that plastic rotation capacity of composite beam decreased to almost half of the capacity of bare steel beam. In order to improve seismic behavior, a gap was provided between concrete slab and column face. However, experimental tests revealed that the application of a gap between concrete slab and column face solely did not improve the rotation capacity. The Finite element study showed that despite the existence of a gap, headed studs contribute to the composite action and modification of stud layout is needed. Investigation about the contribution of studs located on the loaded beam and transverse beam has been conducted. Recommendations for seismic application of composite beam connected to HSS column with large width-to-thickness ratio have been presented.
  • Experimental seismic behavior of a two-story CLT platform building
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): John W. van de Lindt, Jace Furley, M. Omar Amini, Shiling Pei, Gabriele Tamagnone, Andre R. Barbosa, Doug Rammer, Philip Line, Massimo Fragiacomo, Marjan Popovski Cross-laminated timber (CLT) manufacturing and construction has been steadily growing since its inception in Europe in the 1990s. In the US, the growth of the CLT adoption is inhibited by the lack of codified design provisions for CLT in high seismic regions. This led to a multi-year study conducted by Colorado State University to investigate suitable seismic design parameters of CLT shear wall systems. This paper presents the results from a series of shake-table tests featuring a full-scale two-story mass-timber building utilizing CLT Seismic Force Resisting Systems (SFRS). The building was designed using an R- factor equal to 4.0 under the equivalent lateral force procedure specifications of the ASCE 7-16 Standard. The test program included three phases with different wall configurations, reflecting different wall panel aspect ratios and the existence of transverse CLT walls. Test results indicate that the code-level life safety objective was achieved in all test configurations. The addition of transverse walls did not affect the ability of the panels to rock, and improved the performance of the building structural system.
  • Finite element analysis of fatigue crack growth in CFRP-repaired
           four-point bend specimens
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Cheng Huang, Tao Chen, Siyuan Feng This paper presents a finite element (FE) study on fatigue crack growth in carbon fiber–reinforced polymer (CFRP) repaired four-point bend (FPB) specimens with an edge crack subjected to various cyclic loadings (pure mode I, pure mode II and mixed mode I/II). The crack propagation rate was described using NASGRO model together with Tanaka formula, while the crack growth direction was determined by maximum circumferential stress criterion (MCSC). A simulation program was developed using Python scripting in conjunction with FE software ABAQUS to handle the automated fatigue crack growth modelling. The effects of different shear-tension loading ratios (KII/KI) and CFRP layer numbers on CFRP repair performance were first investigated by a comparative analysis of numerical and experimental results. The FE results appeared to be in reasonable agreement with test data in terms of specimens’ failure modes, crack growth trajectories and fatigue lives. Based on the developed program, a parametric study was conducted to gain a deeper insight into the effects of KII/KI ratios, the patching layer number, Young’s modulus and width of CFRP on FPB specimens’ fatigue behavior. The results indicated that the above-mentioned parameters have a significant influence on fatigue crack growth to varying degrees. This work provides an effective way of predicting the fatigue life and mixed mode I/II crack growth trajectories with high computational efficiency and accuracy.
  • Friction characteristics of post-tensioning tendons in full-scale
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Sang-Hyun Kim, Sung Yong Park, YoungHwan Park, Se-Jin Jeon Friction characteristics between the strands and the duct have a significant effect on the distribution of prestressing force and can be incorporated by the curvature and wobble friction coefficients in the design of prestressed concrete structures. However, the recommended friction coefficients show a wide range of variation, which can cause the inaccurate estimation of prestressing force. In this study, the friction coefficients were evaluated based on the strains of tendons measured by Smart Strands using optical fiber sensors in a full-scale test specimen and two actual long-span girder bridges. The test specimen was investigated to determine how the duct shapes and other factors affect the friction coefficients. Simultaneous equations method and least squares method for obtaining friction coefficients were employed and the results were compared in the actual bridges. This study shows one of the applications of the developed Smart Strand system that can overcome several drawbacks of the existing measurement system.
  • Post-fire resistance of internally ring stiffened high performance
           concrete filled steel tube columns
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Talha Ekmekyapar, Ihssan A.H. Alhatmey Use of composite construction is increasing exponentially across the world, since such structures offer the combined benefits of constituent materials and provide cost effective solutions. Concrete filled steel tube (CFST) columns have been proven to be a very efficient way of composite construction. Although the behaviour of CFST columns under many different loading scenarios has been well detailed, a search of the literature revealed few studies on the post-fire resistance of these members. This paper gives an account of internally ring stiffening of CFST columns with the aim of advancing their post-fire resistance. To this end, CFST columns with and without internal rings were subjected to a standard fire exposure. To address their post-fire performance, fire exposed specimens and counterparts without fire exposure (in total 30 specimens) were tested under concentric compression to failure. CFST column specimens were manufactured using self-compacted high performance concrete to acquire key knowledge which could be exploited in highly stressed engineering structures. Experimental results indicate that with a proper design, internal rings are very efficient in providing high post-fire resistances. Some specific configurations achieved post-fire resistances greater than that of the capacities of classical CFST counterparts without fire exposure. Accordingly, it is shown that internal rings have the potential to eliminate the need for external coating or any other expensive fire protection measure to circumvent post-fire design concerns. The findings of this research provide novel insights and offer cost effective solutions to improve the performance of CFST columns under ambient temperature and after fire exposure.
  • Elastic behaviour of a tapered steel-concrete composite beam optimized for
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Martin Paul Nijgh, Ioan Andrei Gîrbacea, Milan Veljkovic Steel-concrete composite beams are widely used in practice because of their simple construction sequence and economic cross-section design. Reuse of traditional composite beams is not possible due to the permanent connection between the steel beam and concrete deck established by welded headed studs. To allow for fast construction, demountability and reuse of composite beams, various demountable shear connectors can be used. In this paper the results of experiments carried out on demountable and reusable tapered composite beams, consisting of a tapered steel beam and large-scale prefabricated concrete decks, are presented. The performance of various arrangements of resin-injected bolt-coupler shear connectors was considered to optimize the beneficial effect of composite action whilst minimizing the number of shear connectors. An advantage of resin-injected bolted shear connectors is that composite action is obtained instantaneously and simultaneously for all connectors. Demountability and reusability of the composite beam were successfully demonstrated experimentally. Experimental and numerical results indicated that the number of shear connectors necessary to fulfil deflection and end-slip limits can be reduced by concentrating them near the supports of a simply-supported beam. Results obtained using finite element models closely matched the experimental results in terms of deflection, stresses and curvature.
  • Structural performance of a shape-adaptive composite hydrofoil using
           automated fibre placement
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): P. Maung, B.G. Prusty, J.M. White, M. David, A.W. Phillips, N.A. St John This paper presents an investigation into structural performance of a shape adaptable composite hydrofoil which was manufactured using Automated Fibre Placement (AFP). The methodology and procedure developed for the complex manufacture using AFP is first described here. A mould originally designed for resin transfer moulding (RTM) was used as a tooling surface for AFP layup. An in-house developed optimisation process for tailored bend-twist behaviour was used to obtain the layup sequence and subsequent tool path creation for AFP fabrication of the hydrofoil. The AFP fabricated hydrofoil was experimentally tested for its structural response using a static cantilever experiment whereas for the dynamic behaviour experimental modal analysis (EMA) was used. Finally, a comparison was made between the structural responses of the optimised hydrofoils manufactured by AFP and using the traditional RTM process.
  • A novel step-wise AK-MCS method for efficient estimation of fuzzy failure
           probability under probability inputs and fuzzy state assumption
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Wanying Yun, Zhenzhou Lu, Kaixuan Feng, Xian Jiang For efficiently estimating the fuzzy failure probability under the probability inputs and fuzzy state assumption (profust model) which generally includes three states, i.e., the absolute safety state, the full failure state and the fuzzy safety-failure transition state, a novel step-wise AK-MCS method is proposed. In the first step, the Kriging model is adaptively updated by U learning function to accurately recognize if the points in the sample pool are in the safety state or in the failure one, where the exact values of performance function at these points are not concerned in the process of updating the Kriging model. After the Kriging model converges so that all points of the sample pool in the absolute safety state and the fully failure state can be well distinguished, the retained points in the sample pool belong to the fuzzy safety-failure transition state and construct the reduced new sample pool. In the second step, the first converged Kriging model continues to be adaptively updated in the reduced new sample pool. The exact values of the performance function at these points locating in the fuzzy safety-failure transition state are concerned for accurately estimating the fuzzy failure probability. Thus, a global learning function based on the total prediction error is used to select training point in order to update the Kriging model. By using the step-wise strategy and collaborating Kriging surrogates through two-step updating processes with different learning functions, the fuzzy failure probability can be efficiently estimated as a post-processing without any extra calls of the performance function. An automobile front model, a simplified wing box structure model and an icing forecast model are used to illustrate the efficiency and accuracy of the proposed method.
  • Experimental estimation of seismic properties of new precast shear wall
           spatial structure model
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Dongyue Wu, Shuting Liang, Mengying Shen, Zhengxing Guo, Xiaojun Zhu, Chongfang Sun Effective seismic properties are a basic requirement in precast shear wall applications. Therefore, this study focuses on the evaluation and improvement of precast shear wall seismic properties using the new pore-forming grouted connector with welded closure confinement steels (NPGCS) developed in previous research. The NPGCS connector reliability was verified and the seismic properties of the NPGCS spatial structure model were evaluated by carrying out a low cyclic reversed lateral loads experimental test on the NPGCS precast shear wall spatial structure model containing superposed connecting beams and precast shear walls, which were selected from a practical high-rise precast residential building. According to the testing results of the crack distribution and component failure modes, the superposed connecting beam properties were weak, and damaged early in the shear failure mode, while the precast shear walls cracked after the steel bars in the superposed connecting beams yielded. Furthermore, the failure mode indicated that the NPGCS connection applied in this spatial model is reliable, while two new weak sections were proven to exist at the connector ends. Together with the precast joint interface slip, the dowel shear action is demonstrated to be harmful to the joint interface properties. Additional seismic parameters, namely capacity, ductility, stiffness and energy consumption, were used to complete the evaluation of the seismic properties of the NPGCS spatial structure model. Overall, although the NPGCS spatial model ductility is low, the strengths are high, leading to continued effective energy consumption properties, which indicates favourable seismic properties of the NPGCS spatial structural model.
  • Hysteretic model for steel piers considering the local buckling of steel
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Shuxian Chen, Xu Xie, Hanqing Zhuge The pier is a vital structural component of bridges and thus critically considered in the seismic design. In order to provide an accurate and efficient methodology in the analysis of seismic response, a hysteretic model considering the effect of local buckling of steel plates is proposed for steel piers. In the hysteretic model, the Giuffre-Menegotto-Pinto hysteresis model is employed to establish the hysteresis curve equation, and the energy-based Ibarra-Krawinkler degradation rule is followed to describe the deterioration rule of structural bearing capacity and stiffness. In this study, a widely used Chinese steel Q345qC was taken as an example to illustrate the proposed model for steel piers. At first, the seismic performance of steel piers under horizontal cyclic load was analyzed. Then, the empirical formulae of the vital limit state points for evaluating the structural seismic performance were established, and further the identification of the decisive parameter (degradation parameter) of the hysteretic model was carried out. Morever, the verification on the effectiveness of the proposed model was verified, and the results showed its applicability and accuracy for steel piers under horizontal cyclic loads. Finally, the application of the proposed model in the seismic calculation of steel piers was interpreted.
  • Efficient assessment of 3D train-track-bridge interaction combining
           multi-time-step method and moving track technique
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Zhihui Zhu, Wei Gong, Lidong Wang, Yu Bai, Zhiwu Yu, Lei Zhang This paper extends the 2D multi-time-step (MTS) method previously proposed by the authors to 3D train-track-bridge dynamic analysis for evaluating in detail the running safety and riding comfort of a train. The train-track-bridge coupled system (TTBS) is separated into the train subsystem, the track subsystem, and the bridge subsystem. These subsystems are coupled by the interaction forces between them. A fine time-step is adopted for the train subsystem and the track subsystem due to the high-frequency wheel-rail contact. A coarse time-step is adopted for the bridge subsystem due to its low-frequency vibration. To reduce the number of degrees of freedom (DOFs) of the track structure, a moving track technique is applied in this paper. The train-track-bridge coupled model with the MTS method is validated by comparing the numerical results with field measurement data of a cable-stayed bridge. A numerical simulation of a train traversing a long-span cable-stayed bridge is used to demonstrate the computational efficiency and accuracy of the proposed method. It is shown that the proposed method is accurate and computationally more efficient than using a uniform time-step for the TTBS.Graphical abstractGraphical abstract for this article
  • Effect of the spatial variability of strength parameters on the dynamic
           damage characteristics of gravity dams
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Xiang Lu, Zhenyu Wu, Liang Pei, Kun He, Jiankang Chen, Zefa Li, Zhe Yang A method to simulate the random field of the strength parameters of gravity dams considering their spatial variability based on the theory of random fields and the autocorrelation function is proposed. Taking a gravity dam project as an example, the elastic modulus and tensile strength are selected as random variables and the corresponding random fields are generated. Based on the concrete damage plasticity (CDP) model, the effects of the spatial variability of parameters on the dynamic response characteristics of gravity dams are expressed from the standpoints of damage development, residual displacement, and energy dissipation. The impacts of the mean value, coefficients of variation, autocorrelation distance, realizations of the tensile strength random field, and seismic inputs on the structural damage are also investigated. It is found that the spatial variability of parameters, especially the tensile strength, has a great influence on the dynamic damage of gravity dams, and that increasing the mean value of the tensile strength can improve their seismic performance.
  • Modelling the behaviour of concrete-encased concrete-filled steel tube
           (CFST) columns subjected to full-range fire
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Kan Zhou, Lin-Hai Han This paper presents an advanced finite element analysis (FEA) model to predict the fire behaviour of concrete-encased concrete-filled steel tube (CSFT) columns. The sequentially coupled thermal-stress analysis method provided in the software package ABAQUS was used. Full-range fire simulation given in this paper included four phases, i.e. loading (to a certain load level) at ambient temperature, standard fire exposure (heating) with the load applied, cooling down phase and postfire loading up to final failure. Calibrated empirical models for steel tube, unconfined and confined concrete (confined by steel tube and by reinforcement, respectively) over the four phases were chosen separately and applied to the FEA model. Numerical results from the model were compared with previously reported results of the experiments on the concrete-encased CFST columns, in terms of ultimate strength at ambient temperature, temperature field, failure modes, fire resistance, axial deformation versus time relationships, load versus axial deformation relationships and postfire residual strength. It is found that acceptable agreement was reached between the predictions and experimental observations, although some aspects could be further improved. Sensitivity analyses on several identified parameters of the modelling were conducted. Recommendations on simulating the full range fire behaviour of concrete-encased CFST columns were proposed based on the numerical study presented in this paper. In addition, the calculated internal force of the tested specimens was extracted and analysed, which confirmed the design concept of the composite action of concrete-encased CFST columns in fire.
  • Cyclic testing of seismic dampers consisting of multiple energy absorbing
           steel plate clusters
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Canxing Qiu, Yichen Zhang, Bing Qu, Chunxue Dai, Hetao Hou, Han Li This paper focuses on a new type of seismic damper consisting of multiple Energy Absorbing Steel Plate (EASP) clusters. To investigate the inelastic behavior of the damper, three full-scale experimental specimens were designed and manufactured. The major test parameter varied in the experimental specimens was the EASP thickness. All the specimens were tested using the same cyclic loading protocol. It was found that all the experimental specimens exhibited the similar bilinear type of hysteretic behavior. None of the experimental specimens developed in-cycle strength degradation. The hysteretic curves of the experimental specimens were full and symmetric. The experimental investigation also demonstrated the post-earthquake replaceability of the EASP clusters in the damper. This paper further presents derivation of an analysis model for the proposed damper. Result comparisons show that the analysis model when used with a proper strain-stress relationship (which takes into account the steel cyclic hardening effect) can provide reasonable predictions for the backbone response of a single EASP, an EASP cluster or the damper. The analysis model can be used in future practice.
  • Mechanics and failure characteristics of hybrid fiber-reinforced concrete
           (HyFRC) composites with longitudinal steel reinforcement
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Wilson Nguyen, Matthew J. Bandelt, William Trono, Sarah L. Billington, Claudia P. Ostertag While the properties of hybrid fiber-reinforced concrete (HyFRC) have been well-reported in the literature, the behavior of reinforced HyFRC (i.e., HyFRC with embedded steel rebar) is less understood. This paper investigates the mechanics and failure characteristics of reinforced HyFRC under direct tension. Samples with a low longitudinal steel reinforcement ratio were studied to evaluate the feasibility of reducing rebar congestion in structural applications through the use of fiber-reinforced concrete. Although reinforced HyFRC forms multiple cracking sites when loaded, rebar strain and HyFRC crack opening are generally concentrated at a single location under post-yield displacements. The onset of rebar plastic deformation and the exhaustion of fibers’ bridging load capacity are coincident events at a dominant crack. For a cracked reinforced HyFRC section to strengthen, the magnitude of load resistance increase from strain hardening rebar must exceed the magnitude of load resistance decrease from fiber pull-out processes. Comparisons are made with studies reported in the literature to demonstrate how longitudinal reinforcement ratio and fiber type influence cracking behavior and ultimate strain capacity. The research presented herein has far-reaching impacts on the structural design of all types of reinforced fiber-reinforced concrete materials detailed for a ductile response under large displacements.Graphical abstractGraphical abstract for this article
  • Block shear failure mechanism of axially-loaded groups of screws
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Ursula Mahlknecht, Reinhard Brandner Self-tapping screws are fasteners that are versatilely applicable in timber engineering. For the design of such screw connections, preferential axial-loading, all possible failure mechanisms have to be considered. Recently, in compact groups of axially-loaded screws the block shear failure mechanism, which has not been investigated so far, turned out to fail rather brittle at load levels lower than currently allowed. This failure mechanism is defined as failure of (rolling) shear and/or tension perpendicular to grain planes encompassing the group of screws. This failure mechanism was observed in groups given a number of different parameter settings, i.e. thread-fibre angles of 90° and 45°, glulam, structural timber and cross laminated timber and various group designs. This paper focuses on groups of axially-loaded screws in glulam and solid timber of Norway spruce (Picea abies) and inserted at a thread-fibre angle of 90°. Varying group sizes, loading and supporting distances and group designs, i.e. various penetration lengths lef and spacing in and perpendicular to grain, a1 and a2, respectively, are analysed by two different “push-pull”-test setups. To predict the block shear capacity and failure characteristics of such groups of screws and to separate this failure mechanism from other failure mechanisms, a mechanical-based block shear model was established. This parallel acting spring model considers load sharing and redistribution between concerned failure planes and depends on a number of material, geometrical and stress distribution parameters. To ensure a reasonable parameter setting, background and potential influencing parameters on each model parameter are discussed. In validation, the model shows overall good predictions of capacities, failure mechanisms and failure sequence for all test series involved. It turned out that the current regulations, comprising the definition of minimum spacing together with minimum edge and end distances, are not sufficient for controlling this three-dimensional block shear failure. In addition, the consideration of the number of screws in the group as well as the penetration length is required.
  • Size effect on seismic performance of high-strength reinforced concrete
           columns subjected to monotonic and cyclic loading
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Zhenbao Li, Chunyi Yu, Yongping Xie, Hua Ma, Zhenyun Tang It has been shown that as concrete strength increases, the size effect becomes more pronounced in both samples and members. However, the effect of section size on the seismic performance of high-strength reinforced concrete columns requires further confirmation. For this purpose, six high-strength reinforced concrete columns were subjected to monotonic and cyclic loading in this study. The experimental results indicate that the relative nominal flexural strength, average energy dissipation coefficient, factor of safety, and local factor of safety all exhibited a strong size effect by decreasing as the column size increased. Moreover, the size effect on the factor of safety was stronger for high-strength columns than for conventional columns. The observed changes in the factor of safety were in good agreement with the Type 2 size effect model proposed by Bažant; so, using the local factor of safety and Bažant’s Type 2 model, the code equation for moment capacity was modified to provide a constant factor of safety regardless of column size.
  • Destructive testing and computer modeling of a scale prestressed concrete
           I-girder bridge
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Cameron D. Murray, Mauricio Diaz Arancibia, Pinar Okumus, Royce W. Floyd Currently, there is a limited amount of published information on failures of prestressed concrete bridges subjected to shear and moment. A scale prestressed concrete bridge was constructed to investigate the ultimate behavior of the bridge with particular focus on load distribution after cracking and on contribution of full-depth diaphragms to structural capacity. A point load was applied at the quarter-span point of the bridge over an interior girder. As the loaded girder failed, the diaphragm-girder connection cracked. Torsion was observed to cause cracking in the exterior girder and the end diaphragm rotated away from the bridge as the deck deformed. A punching shear failure ended the test, however damage indicative of two-way slab behavior was observed in the deck. This failure suggests that post girder failure, the diaphragms provide an important means of load transfer, allowing moment redistribution in the deck and potentially increasing capacity. Testing in the elastic range compared favorably with respect to deflections and shear distribution factors from a grillage model, a 2-D finite element model and a 3-D finite element model.
  • Experimental and numerical study on seismic response of inclined tower
           legs of cable-stayed bridges during earthquakes
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Jiang Yi, Jianzhong Li More than half of cable-stayed bridges adopt the tower with inclined legs, which can be loaded with a combination of bending, torsion, shear and axial force under earthquakes. To study the seismic response of inclined tower legs, shake table tests were conducted on a 1/20 scaled cable-stayed bridge model with an inverted Y-shaped tower. A description of the model design was introduced and observed damages including horizontal and diagonal cracks at inclined tower legs were presented. A numerical model, considering reduction of torsional stiffness of inclined tower legs after diagonal cracking, was established. The feasibility of the numerical model was validated by a comparison of numerical and test results, which showed good correlation in displacement response at tower top and deck end, and cable force. Based on numerical results, the crack torsional moment of the inclined tower could be easily reached at small peak ground acceleration (PGA), leading to a substantial reduction of torsional stiffness of the section. This reduction helped alleviate the torsional moment demand at larger PGAs and delay the torsional failure of the tower legs. Numerical results also revealed that the bending moment is the primary factor to cause concrete cracks at the lower regions of inclined tower legs whereas complex interaction of large bending moment and torsion results in flexural and torsional damage near the intersection. Conventional ways, which adopt an elastic behavior of torsion, either using stiffness prior to or after diagonal cracking, will lead to intensive overestimation or underestimation of torsional response of the inclined tower legs.
  • Seismic control of modularized suspended structures with optimal vertical
           distributions of the secondary structure parameters
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Zhihang Ye, De-Cheng Feng, Gang Wu Suspended building systems with vibration control features dissipate seismic energy by the interaction between their main parts and the suspended parts; they are also architecturally appealing. A modularized suspended structure has been previously proposed to overcome the fragility of its secondary structure and to enhance overall attenuation. However, the full potential of modularization is yet to be achieved via the previous configuration, especially in terms of multi-mode control. In this study, the protection effect of prefabricated modules is further harnessed in such a way that drastic vertical-irregularities of inter-story stiffness and dampers within the suspended segment are allowed. Vertical distribution vectors of structural parameters were set as the variables in genetic-algorithm optimizations, with the maximum mean square moment of the primary structure being the main objective. The results show considerably improved attenuation of responses in multiple modes instead of only the fundamental mode. In the optimized distributions, peaks of damping coefficient occur at the troughs of inter-story stiffness, but without a highly concentrated pattern. Models with different irregularity levels have well-separated Pareto fronts; this indicates that comprehensive improvement can be obtained at compromised choices. The main mechanism is that, with the well-designed irregularities, the secondary structure provides satisfactory dissipation and tuning to the primary structure in the major modes. The analysis with non-stationary excitations reveals that optimized vertical distributions further quicken the vibration decay. The time-history performance verifications and the structural uncertainty analysis are also carried out.
  • Post-fire seismic behavior of two-bay two-story frames with
           high-performance fiber-reinforced cementitious composite joints
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Xiuling Li, Zhenbo Xu, Yi Bao, Zhengang Cong High-performance fiber-reinforced cementitious composite (HPFRCC) has potential to greatly improve the fire resistance and seismic behavior of concrete structures. This paper reports an experimental investigation on post-fire seismic behavior of two-bay two-story frames with HPFRCC joints. Four reinforced concrete frames were fabricated; three of them were tested in compartment fire for 60 min. The fire was regulated following ISO-834 temperature curve. Two different fire scenarios (one- and two-bay fire) were investigated. Two frames were made of monotonic conventional concrete; the other two frames had HPFRCC joints. Each frame was tested under a constant vertical load and a pseudo-static cyclic horizontal load with increased magnitude until the frame failed. The effects of the HPFRCC and fire scenarios on the failure mechanism, hysteretic loops, envelope curve, stiffness degradation, and energy dissipation of the frames were evaluated. The experimental results revealed that the fire exposure reduced the load capacity and deformability of the frames. In the two-bay fire scenario, the use of HPFRCC joints increased the post-fire load capacity by 11%, ultimate deformation by 6%, initial stiffness by 30%, and energy dissipation by 21%. The cyclic behavior of the frame in one-bay fire was better than that in two-bay fire. The frames with HPFRCC joints demonstrated better cyclic behaviors than the virgin reinforced concrete frame.
  • Experimental research on fire-damaged RC continuous T-beams subsequently
           strengthened with CFRP sheets
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Qingfeng Xu, Lingzhu Chen, Chongqing Han, Kent A. Harries, Zhimin Xu This paper presents experimental results of the structural performance of fire-damaged continuous reinforced concrete (RC) T-beams subsequently strengthened with externally bonded carbon fiber reinforced polymer (EB-CFRP) sheets. A series of seven specimens were tested with different fire exposure time and subsequent strengthening techniques. Experimental results showed that both the unexposed control beams and unstrengthened fire-damaged continuous RC T-beams exhibited flexure failure modes and significant redistribution of moment between hogging and sagging regions. The fire-exposed beams had notably degraded strength and stiffness attributable to the internal temperatures exceeding 500 °C for some portion of the exposure. The EB-CFRP strengthening of fire damaged beams was shown to mostly mitigate the effects of fire exposure. The EB-CFRP retrofit measures successfully restored the virgin capacity of the beam and were sufficient to also restore most of the lost initial stiffness. Simple prediction using plane sections analysis and the assumptions of the 500 °C isotherm method [1] were shown to accurately predict the behaviour of the fire-damaged specimens.
  • Repair assessment for distortion-induced fatigue cracks in a seismically
           retrofitted double-deck bridge complex
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Mehdi Motaleb, Will Lindquist, Ahmed Ibrahim, Riyadh Hindi Many steel bridges in the United States designed before the mid-1980s are highly susceptible to distortion-induced fatigue cracking. This vulnerability is substantially increased if the out-of-plane driving force caused by differential girder displacement is increased for any reason. This research examines one such case where a double-deck bridge complex, originally built in the 1960s, was retrofitted to improve seismic performance. As part of the retrofit, single angle K-type diaphragms were replaced with stiffer double-angle cross-type diaphragms. This seismic retrofit led to an increase in web-gap stresses, and within approximately one year following the retrofit, inspectors identified numerous fatigue cracks in the web of longitudinal girders where connection plates terminate near top flanges. A repair measure was implemented to provide a positive connection between the connection plate and the girder flange. The purpose was to reduce the high stress concentrations in the web-gap region by restricting the out-of-plane distortion in the web-gap region. Field tests were carried out in addition to developing finite element (FE) models to investigate the efficacy of the repair technique. The results confirmed a significant decrease in the web-gap stress after implementation of the repair, and a subsequent FE analysis showed that the new load path through the repair angle section did not introduce a new fatigue sensitive area. In fact, the repair resulted in stresses well below the constant amplitude fatigue threshold (CAFT) for this type of detail.
  • Experimental study on demountable steel-concrete connectors subjected to
           combined shear and tension
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Ee Loon Tan, Harshard Varsani, Feiyu Liao Composite beams are being used increasingly in construction due to their benefits over beams consisting of the steel component alone. In some applications such as in composite coupling beams and infill walls, steel-concrete connectors must resist uplift forces in addition to shear forces. Therefore, there is a need to carry out experimental testing to investigate the performance of steel-concrete connectors under combined loading. Furthermore, the separation of the steel and concrete components is a destructive activity and requires remelting of the steel component if it is to be reused. Remelting requires energy that usually comes from unsustainable resources. Hence, research has been carried out in this paper on demountable steel-concrete connectors as they allow demounting and easy separation of the steel and concrete components and reuse.The performance of three types of steel-concrete connectors subjected to combined shear and tensile loading was investigated experimentally. A pull-out test was carried out to determine the tensile resistance of each type of steel-concrete connector. This was followed by a series of modified push tests to determine the interaction between shear and tension loading. Tensile resistance which had been determined from pull-out tests was applied in increments of 25% to each group followed by shear loading until failure of the steel-concrete connector was observed.Based on the experimental investigation carried out, significant reduction in shear resistance was observed when tension was applied. The results are also compared with existing relationships for headed studs under combined shear and tensile loading to determine which relationship is most reliable in predicting the shear-tension resistance interaction of demountable steel-concrete connectors.
  • Structural performance of CFRP-strengthened concrete-filled stainless
           steel tubular short columns
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Alfarabi M. Sharif, Galal M. Al-Mekhlafi, Mohammed A. Al-Osta The use of concrete-filled stainless steel tubular (CFSST) members is relatively innovative and new. CFSST columns can be used for bridge piers, multi-story buildings and other supporting structures. However, a common mode of failure with these type of tubular composite columns is inelastic outward local buckling occurring at the column ends. Therefore, this paper presents the results of experimental, numerical and analytical investigations into the behavior of circular CFSST columns strengthened by carbon fiber reinforced polymer (CFRP) wrap and subjected to axial compression loading. The experimental investigation comprised three series of tests. The main variables tested were the diameter to thickness ratio of the stainless steel tube and the thickness of the CFRP wrap. 3D finite element models (FEMs) were developed for CFRP-wrapped CFSST columns using the ABAQUS software and were validated with experimental results. An extensive parametric study was carried out by using the validated FEMs. It was shown from the experimental and FEMs results that CFRP jacketing was highly effective in improving the axial load carrying capacity and axial shortening capacity of the CFSST columns. Finally, an analytical model based on the FE parametric study results was proposed to predict the axial load carrying capacity of the CFRP-wrapped CFSST columns.
  • A Simplified method to minimize exterior girder rotation of steel bridges
           during deck construction
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Li Hui, Faress Hraib, Brandon Gillis, Miguel Vicente, Riyadh Hindi Wide flange beams are widely used in the United States for bridge design and construction. During the overhang construction of the bridge, torsional loads are often induced due to the fresh concrete load and the use of a deck finishing machine located on the overhang formwork. These torsional moments sometimes cause excessive exterior girder rotation, resulting in many safety and maintenance issues during the construction and service stages. To prevent these issues, most states have specifications for limiting the rotation. Finite element analysis using shell or solid elements is usually recommended for analyzing bridge girders in overhang construction, which can be tedious and difficult in some cases. This study focused on developing a simple method with minimal calculation to evaluate the ratio of unbraced length to girder depth (B/D ratio). The stepwise variable selection method and a regression analysis were conducted to find the relationship between the exterior girder rotation and bridge geometries. A computer program for automatic finite element modeling in SAP2000 was developed using MATLAB, resulting in 4285 finite element models with different bridge geometries being developed to generate artificial data. By conducting a study of variable selection, three parameters were selected based on level of significance. After conducting a regression analysis based on the selected parameters, a method using the normal weight of girder, overhang width, and rotation limit to determine B/D ratio was developed.
  • Editorial for special issue on Sustainable Metallic Structures
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Elyas Ghafoori
  • Influence of masonry infills on seismic response of RC frames under low
           frequency cyclic load
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Ning Ning, Zhongguo John Ma, Pengpeng Zhang, Dehu Yu, Jianlang Wang This paper presents an investigation on the seismic behavior of four reinforced concrete (RC) frames. The study is focused on the effect of the Aerated Lightweight Concrete (ALC) blocks infills on the seismic performance of the RC frames and the interaction between infills and surrounding frames. Four RC frames include a control specimen, frame with full-filled infills, frame with large window openings, and frame with eccentric door openings. Based on the low frequency cyclic loading experiments, hysteretic dissipation ability, stiffness degradation, characteristic displacement and load, failure pattern, flexural moments of columns, effective slab width, required ratio of column-to-beam strength, and column shear force are experimentally investigated and analyzed. Tests results indicate that the strength, the initial stiffness and the area of the hysteretic loop at the same load step were influenced significantly by infills when compared with the frame without masonry infills. This effect was reduced due to the large openings in the frame with infills. The column and beam mixed hinges failure was observed in the frame without infills while shear failure appeared at column ends in frames with infills. The testing results also show that inflection points were shifted to columns top because of the infills. Column shear forces were increased significantly due to the diagonal strut effect. Recommendations on useful effective slab width, the required ratio of column-to-beam strength and the equivalent strut width are made to take masonry infills into consideration in design.
  • Corrigendum to “An empirical approach for nonlinear modelling and
           deformation capacity assessment of RC columns with plain bars” [Eng.
           Struct. 176 (2018) 539–554]
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Gerardo M. Verderame, Paolo Ricci
  • A novel algorithm for longitudinal track-bridge interactions considering
           loading history and using a verified mechanical model of fasteners
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Jun Luo, Zhiping Zeng The mechanical behavior of fasteners has considerable influence on track–bridge interaction (TBI) analysis, and a consensus has been gradually reached that their loading history and nonlinear characteristics should be taken into account. In this study, we present a new variation pattern of the longitudinal resistance of the fasteners considering loading history, which was experimentally verified based on the Dahl friction model. The model’s mechanical behavior was more consistent with measured results compared with previously proposed Ruge’s model and the double-spring model. According to the new model, an algorithm for TBI analysis considering loading history was derived based on the Ritz method and the principle of minimum potential energy, which was applied in a case study of an N-span, simply-supported girder bridge in a high-speed railway with a typical loading sequence: (1) the seasonal temperature change of the bridge; (2) the bending of the bridge structure under a vertical train load; (3) the braking of the train. Additionally, some significant conclusions were obtained by comparing the numerical results and adopting the mechanical parameters of the fasteners specified in various codes, according to both the linear superposition method (LSM) and loading history method (LHM).
  • Static and dynamic analysis of corrugated-core sandwich plates using
           finite strip method
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Hossein Zamanifar, Saeid Sarrami-Foroushani, Mojtaba Azhari Free and forced vibration and static analysis of corrugated-core sandwich plates are investigated in this study by employing the classic finite strip method. The 3D corrugated-core plate is converted to a 2D orthotropic continuum model by considering some equivalent elastic constants. Various boundary conditions and different features of these plates are explored and the geometric and mechanical factors influencing their responses, such as displacements, rotations, moments and shear forces, are evaluated. Because of the significant effect of the shear stiffness on the behavior of corrugated-core sandwich plates, the first order shear deformation theory (FSDT) is used to analyze the plate. Due to the comparatively low shear to flexural stiffness ratio of these plates compared to ordinary plates, the convergence of the results is relatively slow. Therefore, a fast numerical technique such as finite strip method which yields effective reduction of calculation cost is employed. A MATLAB program is developed to obtain the results and the validity of the proposed method is evaluated by comparing the results with those presented by previous researches.
  • RC arch bridge seismic performance evaluation by sectional N-M interaction
           and coupling effect of brace beams
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Kailai Deng, Guihao Yan, Haipeng Yang, Canhui Zhao Reinforced concrete (RC) arch bridges usually sustain remarkable damage from strong earthquakes. To comprehensively investigate the seismic performance of an RC arch bridge, a benchmark RC arch bridge was modeled with the ABAQUS software, and the seismic performance in the longitudinal and lateral directions was determined at different earthquake intensities. In this paper, the seismic responses, i.e., the mid-span drifts, plasticity development, and N-M interactions at the springing, etc., are discussed. The sectional safety factor is proposed to quantitatively describe the damage degree of the springing section under longitudinal excitation. According to the results, this factor successfully indicated the damage status at the springing, and was consistent with the strain development and the N-M interactions. With regard to the lateral excitation, the current design did not consider the contribution from the brace beams. The coupling ratio (CR) is proposed to quantitatively calculate the coupling effect on the two arch ribs from the brace beams. Different CRs were tested to enhance the lateral seismic performance. Finally, the recommended CR was derived.
  • Efficient uncertainty quantification method applied to structural fire
           engineering computations
    • Abstract: Publication date: 15 March 2019Source: Engineering Structures, Volume 183Author(s): Thomas Gernay, Ruben Van Coile, Negar Elhami Khorasani, Danny Hopkin Probabilistic Risk Assessment methodologies are gaining traction in fire engineering practice as a (necessary) means to demonstrate adequate safety for uncommon buildings. This induces a need to apply uncertainty quantification to structural fire engineering problems. Yet, the combination of probabilistic methods and advanced numerical fire engineering tools has been limited due to the absence of a methodology which is both efficient (i.e. requires a limited number of model evaluations) and unbiased (i.e. without prior assumptions regarding the output distribution type). In this paper, the recently proposed MaxEnt method is combined with the dedicated structural fire engineering software SAFIR to evaluate the ability of the method to achieve efficient, unbiased assessments of structural fire performance. The case studies include the probability density function (PDF) of (i) the standard fire resistance of a composite column; (ii) the load bearing capacity of a composite floorplate exhibiting tensile membrane action, after 90 min of standard fire exposure; (iii) the load bearing capacity of the same composite floorplate, considering a parametric fire exposure including cooling phase; and (iv) the maximum temperature reached in a protected steel element under realistic fire exposure. In the first application, the MaxEnt PDF correctly and efficiently captures the distribution obtained using Monte Carlo Simulations. The floorplate example under parametric fire exposure shows the true strength of the MaxEnt method as an unbiased assessment, as different failure modes are observed in the cooling phase resulting in an irregular shape of the load-bearing capacity PDF. For this case, reliance on a traditional assumption of lognormality for the capacity would result in an overestimation of the capacity at lower quantiles. The last case study yields a bi-modal output due to the physics-based duality between localized (traveling) and post-flashover fire development. While the MaxEnt captures this bi-modality, it does not accurately reproduce the distribution obtained by Monte Carlo Simulation. Limitations of the MaxEnt method and needs for further research are discussed at the end of the paper.
  • Effect of combining steel fibers with crumb rubber on enhancing the
           behavior of beam-column joints under cyclic loading
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Basem H. AbdelAleem, Assem A.A. Hassan This investigation aims to study the structural performance of beam-column joints under reverse cyclic loading. Different self-consolidating concrete (SCC) mixtures with various percentages of crumb rubber (CR) and steel fibers (SFs) were tested. The effect of combining different lengths and volumes of SFs with CR on enhancing the ductile behavior of the tested joints was investigated. The main parameters were the percentage of CR (0%-25% by volume of sand), coarse aggregate size (10 mm and 20 mm), concrete type (SCC and vibrated concrete), length of SFs (35 mm and 60 mm), and volume of SFs (0%, 0.35%, and 1%). The structural performance of the tested beam-column joints was evaluated based on load carrying capacity, load deflection response, initial stiffness, rate of stiffness degradation, failure mode, cracking behavior, displacement ductility, brittleness index, and energy dissipation. The results indicated that combining SFs with CR significantly improved the deformability, ductility, energy dissipation, initial stiffness, cracking behavior, first crack load, and load carrying capacity of beam-column joints under reverse cyclic loading. The results also showed that at high percentage of CR (20%), using a larger coarse aggregate (20 mm compared to 10 mm) helped to improve the shear capacity of the joint and changed the failure mode from BJ-mode to B-mode, which enhanced the load carrying capacity, ductility, and energy dissipation of the tested joint.
  • A kinematics-based approach for the shear strength of short
           fibre-reinforced concrete coupling beams
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Boyan Mihaylov Short coupling beams are susceptible to brittle shear failures that are typically suppressed with dense transverse and/or diagonal reinforcement. To reduce the amount of shear reinforcement and improve the service behavior of the beam, researchers have proposed a solution with steel fiber-reinforced concrete (FRC). However, while this solution is promising, there are no sufficiently simple mechanical models capable of capturing the shear strength and displacement capacity of short FRC coupling beams without diagonal reinforcement. This paper proposes such a model based on first principles: kinematics, equilibrium, and constitutive relationships for the mechanisms of shear resistance. The model accounts in an explicit manner for five shear mechanisms across the critical shear cracks: diagonal compression in the critical loading zones, aggregate interlock, tension in the stirrups and in the steel fibres, and dowel action of the longitudinal reinforcement. These mechanisms are predicted and the results are compared to 20 tests from the literature as well as to FEM predictions. It is shown that the proposed approach models well the effect of beam aspect ratio, concrete strength, stirrup ratio, and amount of steel fibres. Furthermore, the model is used to develop relationships outlining the effectiveness of steel fibres to reduce conventional stirrup reinforcement in coupling beams with various properties.
  • On the structural energy distribution and cumulative damage in
           soil-embedded foundation-structure interaction systems
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Ehsan Ahmadi Repeated cyclic loading is well-known to have detrimental effects on inelastic response of structures. Distribution of structural energy and quantification of cumulative damage effects are very important components in performance-based seismic design approach. On the other hand, soil-foundation-structure interaction effects significantly influence inelastic response of structures through the soil contribution to modification of dynamic characteristics of the structure. Hence, this study focuses on structural energy distribution and cumulative damage effects in structures with embedded foundations considering collective effects of kinematic and inertial interactions. To achieve this goal, a soil-foundation-structure interaction system well suited for parametric study was considered: the soil surrounding the rigid foundation was modelled as a half-space, the embedded foundation was modelled using a stack of discrete disks and applying double cone model concept, and the structure was considered as a single-degree-of-freedom structure. The soil-foundation-structure interaction systems were defined according to key interaction dimensionless parameters and were then analysed subjected to 40 non-pulse far-fault ground motions. It is found that SFSI effects significantly alter total energy, viscous damping energy, and hysteretic damping energy of the structure. The results also show that considering only inertial interaction increases cumulative damage index of the structure while inclusion of kinematic interaction has a decreasing effect. Furthermore, practice-oriented correction factors to cumulative damage index of fixed-base structures are proposed to return cumulative damage index of soil-foundation-structure systems. This study can find use in damage evaluation of existing structures with embedded foundation on soft soils.
  • Experiment-based numerical simulation of hybrid structure consisting of
           wooden frame and rigid core
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Di Wu, Yoshihiro Yamazaki, Sayoko Sawada, Hiroyasu Sakata In 2001, the Japanese government released a law to promote the use of wood in public infrastructure. As a response, a series of 1/3-scaled shaking table tests were conducted to investigate the seismic performance of wooden horizontal hybrid structure. Based on the tests, a discrete numerical model was built in OpenSees and the accuracy of the model was verified. A total of 8 ground motions were chosen as the input and scaled to have the same value of spectral acceleration with BCJ-L2 wave at the acceleration constant area. The peak ground acceleration of BCJ-L2 was set to 0.8 g to excite the elastic deformation of the wood part. Parameter analysis was then performed using the built model and the chosen ground motions. The aim of this research was to extend the result of the 1/3-scaled shake table tests to provide a quantitative evaluation on the influence of some concerned design features of the wooden horizontal hybrid structure. Results indicated that the increase of core-wood stiffness ratio and the diaphragm-wall stiffness ratio would significantly mitigate the seismic deformation of the wood part at the cost of the increase of seismic force at the core part and the connection. Some specified values for the design features were suggested and a simple method to evaluate the shear distribution between the diaphragm and the shear wall was proposed.
  • Crash performance evaluation of a new movable median guardrail on highways
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Jian Yang, Guoji Xu, C.S. Cai, A. Kareem In this study, a new movable median guardrail is proposed to overcome the structural defects of and to improve the low anti-collision performance of two conventional central/ median guardrails comprising of the concrete and W-beam. The design parameters of this movable median guardrail are optimized based on the uniform design method and a linear weighted combination method in accordance with the requirements given in the National Cooperative Highway Research Program (NCHRP) Report 350. This proposed guardrail is systematically evaluated in terms of its energy absorbing capacity, vehicular acceleration, post-impact trajectory of the impacting vehicle, and behavior of the guardrail upon impact through a three dimensional computer simulation using LS-DYNA code. In the evaluation process, performance comparisons of the moveable median guardrail are made with the concrete and W-beam guardrails. The results shows that the performance of the proposed movable median guardrail is superior as compared to the conventional concrete and W-beam guardrails as it offers: a higher level of crash performance is exhibited, the occupants of the impacting vehicle is better protected, and the impacting vehicle exhibits better post collision stability.
  • High-performance self-centering steel columns with shape memory alloy
           bolts: Design procedure and experimental evaluation
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Bin Wang, Songye Zhu, Can-Xing Qiu, Hao Jin Steel moment-resisting frames are popular structural systems used extensively around the world. However, conventional column base connections are vulnerable to large residual deformation after strong earthquakes. By contrast, shape memory alloys (SMAs), which are high-performance metallic materials, can experience large strains and still recover their initial shape through either heating (shape memory effect) or unloading (superelastic effect). The superelastic behavior of SMAs is appealing to the earthquake engineering community because of the material’s excellent self-centering (SC) and energy dissipation capabilities. In this paper, a novel type of steel columns equipped with NiTi SMA bolts was introduced and its potential for achieving earthquake resilience were investigated. Structural details of the column base and mechanical properties of the SMA bolts were described first. Subsequently, an analytical model of the SC column for different limit states and the corresponding design procedure were presented. The seismic behaviors of two steel column specimens were experimentally tested to investigate the effects of the initial prestrain in the SMA bolts and the axial compressive force in the column under cyclic loading. Results showed that the steel columns equipped with SMA bolts exhibited satisfactory and stable flag-shaped hysteresis loops with excellent SC and moderate energy dissipation capabilities. More importantly, SMA bolts with prestrain could still be tightened after removal of lateral force. Therefore, the proposed SC column could achieve seismic resilience design that requires no (or minimal) repair even after strong earthquakes and remains highly functional for aftershocks or future earthquakes. In addition, the analytical model was verified through a comparison with test results obtained at key limit states.
  • Seismic performance of irregular RC frames designed according to the DDBD
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): P. Giannakouras, C. Zeris The Direct Displacement-Based seismic Design (DDBD) method has been a major development in the context of Performance-Based seismic Design of reinforced concrete (RC) frames. The method has been positively received from the engineering community, while, at the same time, significant improvements have been proposed. Even though its field of application is constantly widening, no specific rules are generally provided for specific cases, such as RC frames with setback irregularity, under the claim that, in this case, no modifications in the basic approach are needed. The validity of this assumption is examined by assessing the DDBD provisions through design of such irregular RC structures and assessment of their seismic performance under non-linear static and dynamic analyses. Local ductility associated with global behavior is examined and incompatibilities in demands with the global design displacement are identified, where they occur. Guidelines are provided to ensure that rational performance results are obtained, when the DDBD method is applied.
  • Computation of frequency responses and their sensitivities for undamped
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Baisheng Wu, Shitong Yang, Zhengguang Li, Huixiang Zhong, Xin Chen This paper presents a numerical method for calculating the frequency response and its sensitivity of an undamped system in a frequency interval. The Sturm sequence number is first used to adaptively determine the number of the lowest modes that need to be calculated. The corresponding modes can be computed by the Lanczos or subspace iteration methods. The complementary portion of contribution of these computed modes is then transformed into the solution to a new system by using the mass orthogonality. The solution of the new system is approximated by the partial sum of the convergent power series of the excitation frequencies, and the number of items therein can be adaptively determined by utilizing only the highest excitation frequency. The sensitivity expression of the frequency response is also established. The resulting expressions of the frequency response and its sensitivity are valid for the entire range of excitation frequencies of interest. By changing only the excitation frequency, we can obtain frequency responses and their sensitivities. This computational methodology is illustrated by its applications to two examples. The results show that the proposed method can remarkably reduce the CPU time required by the direct method.
  • Experimental study on seismic behavior of high-strength circular
           concrete-filled thin-walled steel tubular columns
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Jiantao Wang, Qing Sun, Junxin Li This paper presents the results of an experimental study on the seismic behavior of high-strength circular concrete-filled thin-walled steel tubular (HCFTST) columns with ultra-large diameter-to-thickness (D/t) ratios exceeding the limitations of the current construction standards. Sixteen HCFTST columns with different combinations of D/t ratio, concrete cylinder compressive strength (fc), and axial compression ratio (n) were tested under constant axial compression combined with cyclic lateral loading. The ultimate failure state was achieved when the steel tubes ruptured severely and core concrete crushing occurred. The results from hysteretic curves indicated that the HCFTST columns with ultra-large D/t ratios displayed flexural failure and shear failure modes. Subsequently, the skeleton curve, ductility, energy dissipation capacity, and stiffness degradation were discussed in detail. Moreover, the effects of D/t ratio, concrete cylinder compressive strength and axial compression ratio on performance were investigated so that this work could serve as a basic reference to future studies, and a strength model was proposed to predict the moment-resisting capacity. The experimental investigation indicated that (i) using high-strength Q690 steel could significantly contribute to a larger elastoplastic deformation capacity and delay the onset of post-peak behavior, even though a lower ductility capacity was provided; (ii) the proposed strength model could satisfactorily predict the moment-resisting capacity; (iii) the out-of-code HCFTST columns with reasonable design could demonstrate favorable seismic behavior and could be accepted as aseismatic components in earthquake-prone regions.
  • Hencky Bar-Chain model for buckling analysis of non-symmetric portal
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): W.H. Pan, C.M. Wang, H. Zhang This paper presents the development of the Hencky bar-chain model (HBM) for the buckling analysis of non-symmetric portal frames under vertical compressive axial loads on the columns. Generic stiffness and geometric matrices are derived for the frame buckling analysis. Based on these matrices, a simple computer code is developed to determine the buckling loads. Illustrative frame buckling problems are solved to demonstrate the ease and simplicity of the HBM for analysis of different and complex design conditions imposed on the frames. The advantages of consistent formulation, localized model modifications, and convenience in obtaining the buckling modes are further noted for the HBM.
  • Probabilistic hurricane risk analysis of coastal bridges incorporating
           extreme wave statistics
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Arash Saeidpour, Mi G. Chorzepa, Jason Christian, Stephan Durham Coastal bridges sustained severe damage during hurricanes Ike, Katrina, and Ivan. Reducing the impact of future hurricane events to coastal bridges requires conducting a comprehensive risk analysis. A comprehensive risk analysis of bridges enables owners to assign limited resources to the most critical bridges in the inventory through a risk-informed decision making process. This study presents a computationally efficient methodology for structural fragility analysis and risk assessment of simply supported coastal bridges vulnerable to hurricane hazard. Various sources of uncertainty associated with hurricane hazard and bridge response are identified, and thereby establishing probability distributions. The novelty of the proposed method includes the consideration of uncertainties in extreme wave heights and wave period by means of a wave spectral density distribution in the calculation of wave forces. The proposed hurricane risk analysis method was successfully applied to coastal bridges located in the state of Georgia (U.S.A). The application presents the derivation of probabilistic models of demand, capacity and hazard; and highlights the potential of the proposed framework for identification and ranking of the most vulnerable bridges.
  • Seismic behavior of encased CFT column base connections
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Xian Li, Tao Zhou, Jian Li, Xiao-Bo Kuang, Yu-Wei Zhao The vulnerability of traditional encased column base connections, which consist of inner base-plate column bases partially encased by reinforced concrete outer components, has been demonstrated by previous earthquakes. This paper presents a new type of encased column base connections using steel wraps to confine reinforced concrete outer components, and the seismic behavior of both the traditional and the proposed encased concrete filled steel tube (CFT) column base connections was experimentally studied by testing of eight large-scale specimens under simulated seismic loads. The test parameters mainly included thickness, height and flexural reinforcement ratios of outer components, with or without steel wraps and shear studs. The effects of the test parameters on the failure modes, load-deformation response curves, stiffness, strength, ductility, energy dissipation ability and strain distribution of the encased column base connections were comprehensively evaluated. The test results indicate that encased column base connections with properly design can achieve desirable seismic behavior and the use of steel wraps can effectively prevent the shear cracking of reinforced concrete outer components. Finally, the methods of predicting the flexural strength of encased CFT column base connections were also discussed.
  • Experimental and numerical verification on effects of inelastic tower
           links on transverse seismic response of tower of bridge full model
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Wen Xie, Limin Sun This paper aims to verify the effects of inelastic tower links on mitigating the transverse seismic response of towers for super long-span cable-stayed bridges under unidirectional uniform earthquake excitations. A 1/70-scale bridge full model of a preliminary design super long-span cable-stayed with a central span of 1400 m was designed and tested on a shaking table array. The bridge full model included superstructure, pile groups and artificial soil placed in laminar shear boxes. Inelastic tower links used as sacrificial links scheme were installed in the top region between both tower shafts in the transverse direction. The dynamic characteristics and seismic responses of the bridge full model with and without the inelastic tower links were analyzed and compared under various uniform earthquake excitations in the transverse direction. The experimental results show that the addition of inelastic links to the tower improves the seismic performance of the cable-stayed bridge, and the tower seismic demands are reduced, including the displacement and strain responses. Especially, the inelastic tower links significantly decrease the strain responses in the tower top region. It is indicated that the inelastic tower links can tune the seismic response and mitigate the seismic damage of towers in high seismic regions. Moreover, an updated finite element (FE) model was conceived to replicate the experimental results using OpenSees, and the numerical simulations of the bridge full model were performed. Consequently, the numerical results are in good agreement with the experimental counterparts, thus validating the effectiveness and accuracy of the updated FE model.
  • Failure analysis of punching in reinforced concrete flat slabs with
           openings adjacent to the column
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Elyson A.P. Liberati, Marília G. Marques, Edson D. Leonel, Luiz C. Almeida, Leandro M. Trautwein One of the main collapse modes of reinforced concrete flat slabs is the punching of the slab-column connection in which the load is applied in a reduced area. Such condition generates significant shear stresses in the slab region around the column. This failure mode should be avoided in order to provide conditions for the development of reinforcements yielding and bending collapse mechanisms prior to the occurrence of shear failure. Then, brittle failure and progressive collapse are prevented. In this study, 12 flat reinforced concrete slabs with dimensions 1800 mm × 1800 mm × 130 mm without shear reinforcement subjected to symmetrical loading were analysed experimentally. These slabs were divided into three groups according to the amount of openings adjacent to the column. The collapse load values and the failure modes were analysed. The results obtained experimentally were compared with results available in the literature, as well as with responses predicted from the normative instructions.
  • Modelling mixed mode fracture of mortar joints in masonry buildings
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): M. Bisoffi-Sauve, S. Morel, F. Dubois Within the framework of Discrete Element Modelling of masonry structures, a contact law based on Cohesive Zone Model and Coulomb’s law is proposed to describe the fracture behaviour of mortar joints. The contact law is expressed in mixed mode I + II and is based on the cohesive behaviours of pure modes I and II and on the frictional behaviour whose parameters can be estimated from an experimental procedure consisting in two fracture tests. Moreover, it is shown from numerical simulations that the contact law exhibits a load path dependency in agreement with the quasi-brittle behaviour expected for mortar. Finally, a parametric study performed from the simulation of the diagonal compression of a masonry panel shows a good agreement of the obtained load-displacement responses and failure modes compared to experimental results of the literature.
  • Probabilistic calibration for development length models of deformed
           reinforcing bar
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Bo Yu, Ruikai Tang, Bing Li In order to provide a scientific basis for choosing the appropriate development length models, a probabilistic calibration method was developed to comprehensively evaluate the accuracy and applicability of seven typical deterministic development length models for deformed reinforcing bars (rebar) in normal and high-strength concrete. The influences of important factors (including compressive strength of concrete, concrete cover thickness, rebar diameter, tensile stress of reinforcement bar, residual tensile strength of cracked concrete, friction on bearing surface and effective bearing angle) on development length were investigated based on the partly cracked thick-walled cylinder model. Then a probabilistic development length model involving both aleatory and epistemic uncertainties was proposed based on the Bayesian theory and the Markov Chain Monte Carlo (MCMC) method. Meanwhile, key probabilistic characteristics of development length were presented and a probabilistic method was suggested to calibrate available deterministic development length models based on the confidence interval and the confidence level. Finally, the accuracy and applicability of available deterministic development length models under different conditions were calibrated comprehensively.
  • Shear size effect in simply supported RC deep beams
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Hui Chen, Wei-Jian Yi, Zhongguo John Ma The shear size effect refers to the phenomenon that the shear strength of reinforced concrete (RC) beams decreases as the beam depth increases. The shear strength of RC deep beams is sensitive to boundary conditions (in this case, load- and support-bearing plate (or column) sizes), which in turn affect the shear size effect of deep beams. In this study, to separate and identify the influences of the bearing plate size on the shear size effect, existing deep beam tests on shear size effect are classified. It is verified that the shear size effect of deep beams with a fixed bearing plate size is stronger compared to deep beams with proportionally varied plate sizes. By using a non-linear analysis software ATENA based on concrete fracture and plasticity theory and a mechanical model called cracking strut-and-tie model (CSTM), the shear size effects of the classified test groups are accurately predicted, and the maximum height of each beam group is extrapolated to 4 m. Through in-depth analysis of the finite element model and CSTM results, it is inferred that the possible reasons that lead to the shear size effect of RC deep beams are: (1) bearing plate size effect, that is the reduced relative strut width caused by the disproportionately varied bearing plate size with the beam height; and (2) beam depth effect, which refers to the deterioration of the shear transfer strength by aggregate interlock of the critical shear crack due to the increase of the beam depth. In addition, based on the prediction results for the 4 m high beams and the existing test results, the STM in the ACI 318-14 is evaluated. The results show that the ACI STM can not inherently consider the beam depth effect, resulting in the safety of large-size deep beams designed according to the ACI STM is lower than that of small-size deep beams. For this reason, proposals for considering the beam depth effect in STM design are put forward.
  • Continuous one-dimensional model of a spatial lattice. Deformation,
           vibration and buckling problems
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): A.M. Guzmán, M.B. Rosales, C.P. Filipich Lattice towers and guyed masts are frequently used in the telecommunication industry, particularly to support antennas. These structural systems comprise a large number of elements (mainly, legs and diagonals) and for this reason, their representation by equivalent models is quite common and convenient. In a previous study, the authors derived a continuous model of a spatial lattice governed by nine differential equations (9DE). The legs trace forms a triangle and the diagonals with a zig-zag pattern are contained in three planes that join each two legs, defined as Pattern 1. Here and starting from an energy statement, the structural behavior of a 1D continuous model governed by six differential equations (6DE) which leads to a simpler representation of the lattice structure, is stated. This formulation considers the shear flexibility and the second order effect due to axial loads. Also, the inertial forces due to the legs and diagonals masses are taken into account. Numerical examples dealing with deflections, critical buckling loads and natural frequencies are solved with this 1D model. The results are compared with the outcomes found with finite element methods. A very good performance is attained with the proposed model. Finally, the equivalent properties for other patterns of diagonalization (Patterns 2, 3 and 4) different to the studied as well as the formulas to find the critical loads are included in Appendices.
  • Random fatigue of plane frames via lumped damage mechanics
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): José A.V. Bazán, André T. Beck, Julio Flórez-López Fatigue of metal structures has long been recognized as a random process, subject to significant uncertainties. To avoid excessive conservativeness, design and maintenance of such structures require explicit consideration of uncertainties in material properties and loading. This can severely impact computation times, when numerical models are employed in the analysis. In this context, this paper presents a novel application of Lumped Damage Mechanics (LDM) to the random fatigue analysis of plane frames subject to cyclic loading. The method is based on the observation that, in plane frames subject to dynamic loading, fatigue damage concentrates at the joints. Parameters of the proposed lumped damage model are obtained from parameters of linear elastic fracture mechanics. These parameters are calibrated in a cantilever beam problem, for which S-N data is given in building codes. Efficiency of the method is then demonstrated in application to 6 and 25-element plane frames. The proposed method has obvious applications to the reliability-based design and maintenance scheduling of frame structures subject to random wind and wave loadings.
  • Strength of pile caps under eccentric loads: Experimental study and review
           of code provisions
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Lucia Miguel-Tortola, Pedro Francisco Miguel, Luis Pallarés Pile caps are rigid reinforced concrete structures that transfer column loads, generally consisting of a combination of an axial load and bending moments in one or two directions, to the piles. The design formulations of pile caps for more than two piles were derived from the results of experimental tests under a centered load. The practice of checking both punching and shear failure modes is common as described in the literature review, even though these formulations were developed for more slender elements. Currently, Codes ACI 318-14 and EC2 allow designing pile caps with strut-and-tie models or sectional approaches (shear, punching and flexural designs).In this study, 21 full-scale pile caps with different shear span-depth ratios and reinforcement layouts were studied to investigate the effect of eccentric loading on the strength and accuracy of the code formulations. The results show that in eccentrically loaded pile caps, the ultimate load is reduced but the maximum pile reaction increases and the secondary reinforcement proves effective to enhance the pile cap strength.Although the strut-and-tie models (STM) allow eccentric loads to be taken into consideration, they predict a much lower peak load than that observed at the experimental results and do not adequately reflect either the influence of slenderness or the failure mode.In general the sectional approach provided by Codes ACI-318-14, EC2 and MC-2010 (Level I of Approximation) lead to safe predictions of the peak load but do not always correctly predict the failure mode. The ultimate load predicted by EC-2 formulation comes closest to the experimental peak load, accurately reflects the influence of slenderness and the effect of secondary reinforcement, however, additional assumptions need to be made for its application. The ACI formulation complemented by the CRSI-2008 Special Investigation for deep pile caps is the safest but does not adequately capture the effect of horizontal and vertical secondary reinforcement. The MC2010 LoAI formulation is also conservative but does not detect the influence of slenderness or the contribution of secondary reinforcement.
  • Experimental study of in-plane shear strength of confined concrete masonry
           walls with joint reinforcement
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): A.I. Cruz O., J.J. Pérez-Gavilán E., L. Flores C. Six full-scale confined masonry walls made with multi-perforated concrete units were subjected to reversal cyclic lateral loads. The only variable investigated was the amount of joint reinforcement. All other variables were fixed, the height to length aspect ratio was set to one. The reinforcement, placed in the bed joints every two courses, consisted in small diameter bars with 588 MPa nominal yielding stress. Numerous strain gages were installed on the rebars to monitor deformation and subsequently estimate the lateral strength contributed by the reinforcement. The strength due to the masonry was estimated as the difference between the total lateral strength and the strength attributed to the reinforcement. The results show that the contribution of the reinforcement to the lateral strength increases with the amount of reinforcement to a certain limit and that the contribution of the masonry decreases. The limit is related to the masonry compressive strength. The experiments and results are presented in detail, followed by a discussion and conclusions.
  • Levy solution for bending response of FG carbon nanotube reinforced plates
           under uniform, linear, sinusoidal and exponential distributed loadings
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Mohammed Sobhy A new analytical approach for bending response of functionally graded single-walled carbon nanotube (FGCNT) reinforced plate resting on double-layered elastic foundations in thermal environments is presented based on Levy and Navier types solutions. The distribution of the carbon nanotubes is varied through the plate thickness in accordance with a modified power law. Four types of carbon nanotube distributions are considered. The four edges of the plate are simply supported for Navier method, whereas for Levy method, two opposite only of them are simply supported and the other ones are arbitrary. The present FGCNT plate is subjected to uniform, linear, sinusoidal or exponential distributed loadings. A refined shear deformation plate theory with four unknown functions is employed to obtain the closed form solution. The four coupled governing partial differential equations are derived utilizing Hamilton’s principle. Applying Levy solution and then the state space concept to the governing equations, a nonhomogeneous first-order linear ordinary differential system with constant coefficients is obtained. The solution of the homogeneous system (homogeneous solution) is obtained by using the matrix method. While, the method of undetermined coefficients is applied to find the particular solution of the nonhomogeneous linear system. The results obtained by Navier and Levy methods are compared with available results in the literature. Several examples are discussed for various values of the foundation stiffness, CNT volume fraction, various types of plate geometries, CNT distributions, external applied loads and boundary conditions.
  • Intervention cost optimization of bracing systems with multiperformance
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): F. Braga, R. Gigliotti, R. Laguardia In this paper a multiperformance optimization procedure to design dissipative bracing systems controlling the structural performance while minimizing the intervention cost is proposed. The procedure allows dimensional and topological optimization of bracing, considering inelastic behaviour of braced structures through properly developed visco-elastic equivalent linearization schemes. The structural behaviour is controlled through constraint functions on interstory drift ratio (IDR) while the intervention cost is explicitly encountered by considering real costs that mainly influence it. The procedure is suitable for both new and existing structures, however the objective function is specialized on typical costs of retrofit interventions. A numerical example on a multistory frame has been developed in order to show the effectiveness of the procedure to provide the optimal characteristics and arrangement for the braces, while the suitability of linear equivalent schemes to predict the structural response is investigated through Nonlinear dynamic analyses. Further, a comparison of the estimated intervention costs by asking for different performance levels is performed, showing how the proposed objective function is able to help the designers to identify the ideal performance levels and acceptance criteria to reduce the cost-benefit ratio.
  • Influence of mean period of ground motion on inelastic drift demands in
           CBFs designed to Eurocode 8
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): John Hickey, Brian Broderick The influence of mean ground motion period, Tm, on the inelastic drift response of steel Concentrically Braced Frame (CBF) structures designed to Eurocode 8 is investigated. Incremental dynamic analysis is performed for a set of case study frames with varying structural characteristics at four different seismic intensity levels. From the results of these analyses, regression models for predicting both global and inter-storey drift are developed. It is shown that that both global and inter-storey drift tend to increase nonlinearly as the ratio of fundamental structural period to mean ground motion period, T1/Tm, decreases below unity. The rate of this increase is dependent on the ground motion intensity, represented by the EC8 behaviour factor q. The first mode participation factor, relative storey stiffness and column-to brace stiffness are also shown to influence inter-storey drift response. The values of drift predicted by the developed regression models are compared to values predicted by design codes as well as other predictive models developed in previous studies. It is observed that design codes can under predict drift at lower T1/Tm values.
  • Reliability calibrations for the design of cold-formed steel portal frames
           by advanced analysis
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Francisco Sena Cardoso, Hao Zhang, Kim J.R. Rasmussen, Shen Yan The steel industry is developing a design-by-advanced analysis specification for cold-formed steel construction. This effort provides an opportunity to utilize the latest nonlinear structural analysis (advanced analysis) to design steel structures based on their overall system behaviour. This paper concerns the system reliability calibrations of this design-by-analysis method, with a particular focus on cold-formed steel portal frames. Four typical portal frames are considered. The system reliability assessment takes into account all important random variables. A limit-state design criterion is developed which is consistent with a desired level of system safety.
  • New non-destructive dynamic tensile testing of prestressing fine-rolled
           screw-threaded steel bars
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Xingu Zhong, Tianyu Zhang, Chao Zhao, Xiaojuan Shu, Mingyan Shen, Yohchia Frank Chen This paper presents a new non-destructive dynamic tensile test for fine-rolled screw-threaded steel bars (FSSBs) in prestressed concrete box-girder bridges. In this study, the anchorage nut and anchor plate are connected by a coupling spring, so are the steel bar and nut threads. A discrete dynamic model of a spring–mass system was therefore established to evaluate the bending vibration of the anchorage system. The tensile force in prestressing FSSBs can be determined indirectly using the measured natural frequency of the exposed section. Based on the force transmission characteristics of threads, a frequency correction equation is proposed to correct the test error in the tensile force. The laboratory model and field tests of multiple bridges show that the proposed test method for tensile force is feasible and practical. The proposed tension test method is rapid, non-destructive, and can be used repeatedly. It has no impact on the construction and offers potential wide applications. The study results are significant in terms of the testing and analysis of the induced tensions in mechanical components and similar structures of civil engineering.
  • Experimental analysis of one-way composite steel deck slabs voided by
           circular paper tubes: Shear strength and moment–shear interaction
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Chang-Hwan Lee, Iman Mansouri, Eungsoo Kim, Jaeho Ryu, Woon-Taek Woo In order to improve structural efficiency, environmental performance, and constructability, a new type of one-way composite voided slab system (TUBEDECK) has been recently proposed which combines profiled steel decks with cast-in-situ RC slabs. Because eliminating concrete volume to optimize flexural strength can significantly reduce the shear strength of nonprestressed concrete or composite slabs without shear reinforcement, a clarification of the shear resistance capacity is required. In this study, shear tests on a total of 12 specimens were conducted with slab thickness, the presence or absence of voids and/or steel decks, and tension reinforcement ratio as variables. The results show that combined flexure and shear dominated the behavior of both voided (V) slabs and TUBEDECK (TD) slabs, and web-shear cracking did not affect strength. Predicted shear strength based on the minimum web width was too conservative. Conversely, the shear strength prediction equations, which were proposed on the basis of the real cross-sectional area of concrete, predicted the capacity of both V slabs and TD slabs from a reasonably conservative perspective. A discussion on the influence of moment–shear interaction is also included, and an interaction design model is proposed in a further investigation.
  • Low-cycle fatigue performance assessment of current Japanese steel
           beam-to-column connections determined by ductile fracture
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Shoichi Kishiki, Dong-Seok Lee, Satoshi Yamada, Takanori Ishida, Yu Jiao A methodology for low-cycle fatigue (LCF) performance assessment of beam-to-column connections commonly used in current Japanese steel moment-resisting frames, such as welded flange-bolted web connections and welded connections with rectangular hollow section columns, is presented in this paper. The proposed assessment methodology is based on an empirical relationship between the number of cycles to failure and beam rotation amplitude obtained from a database of cyclic loading test results. In the empirical relationship, the effects of decreasing the moment transfer efficiency at the beam web-to-column connection due to the slip behavior of the bolts, the out-of-plane deformation of the column flange and the loss of web section due to the weld access hole are considered. The proposed approach can be applied to evaluate the comprehensive fatigue performance of current Japanese beam-to-column connections, considering the moment transfer efficiency of the beam web-to-column connection details and the steel grade.
  • Pre-design of laterally supported stair steps
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): José Santos, Pedro Andrade, Patrícia Escórcio It is becoming increasingly common to design monumental staircases and their steps with elevated stiffness and low mass, obtaining high natural frequencies, off the range of frequencies that are excitable by pedestrians. However, this sometimes leads to unacceptable levels of vibration, with impulsive responses. In many cases the dynamic behaviour of steps is almost independent from the rest of the staircase, causing a phenomenon designated as local vibrations, which could be much more severe than the global vibrations of the staircase.In order to avoid this problem, this paper presents a simplified expression to pre-design stair steps which guarantee that excessive vibrations will not occur, without the need to perform a dynamic analysis. The expression was deduced based on the results of an experimental campaign, several numerical analyses and a theoretical analysis. During this study it was necessary to define an acceptable limit of vibrations specific for this type of vibration, which affects mainly the feet of pedestrians. The expression deduced is easy to apply because it depends only of vertical stiffness of the step. Finally, the pre-design expression is also applied to the staircase used in the experimental campaign, and it was concluded that it would be easy to avoid excessive vibrations, with a negligible cost increase.
  • Flexural behavior of geopolymer-concrete beams longitudinally reinforced
           with GFRP and steel hybrid reinforcements
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): G.B. Maranan, A.C. Manalo, B. Benmokrane, W. Karunasena, P. Mendis, T.Q. Nguyen This paper presents the flexural behavior of geopolymer-concrete beams longitudinally reinforced with a hybrid of glass-fiber-reinforced-polymer (GFRP) and steel bars. Seven geopolymer-concrete beams with different ratios and configurations of GFRP-to-steel reinforcement were designed, cast, and tested up to failure using the four-point static bending test. Based on the experimental results, the hybrid beams showed better serviceability and ductility and up to 15% higher strength than their counterpart geopolymer-concrete beams reinforced solely with GFRP bars. Increasing the reinforcement ratio increased overall beam performance. The hybrid beams reinforced with steel bars at the top and with GFRP bars at the bottom produced higher stiffness and strength at concrete crushing than their counterpart beams with hybrid tensile reinforcement. The tested geopolymer-concrete hybrid beams yielded better bending-moment capacities than the normal-concrete hybrid beams. Both ACI 440.1R-15 and CSA S806-12 conservatively predicted the flexural strength and mid-span deflection at service load of the hybrid beams.
  • Using tuned mass damper inerter to mitigate vortex-induced vibration of
           long-span bridges: Analytical study
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Kun Xu, Kaiming Bi, Qiang Han, Xiaopeng Li, Xiuli Du The undesirable vortex-induced vibration (VIV) may seriously influence the fatigue life and serviceability of bridge structures. It is important to take countermeasures to suppress the adverse VIV of long-span bridges. In the present study, a novel inerter-based system, namely the tuned mass damper inerter (TMDI), is proposed to control the VIV of the main deck of long-span bridges. In this system, an inerter device, which is able to transform the linear motion into the high-speed rotational motion and thus significantly amplifies the physical mass of the system, is incorporated into the conventional tuned mass damper (TMD) system to further improve the performance of TMD. An applicable layout of the TMDI inside the bridge deck is introduced and the governing equations of the structure-TMDI system subjected to VIV are established. The optimization of the TMDI parameters with the consideration of nonlinear aeroelastic effect is derived. The control performance and robustness of the proposed system are investigated through an analytical case study in both the time and frequency domains. It is observed that the TMDI system can obviously reduce the VIV responses of the bridge deck. Moreover, compared to the conventional TMD system, the static stretching of the spring due to gravity and the oscillation amplitude of the mass block in the TMDI system are significantly reduced. These properties make the proposed TMDI system an attractive alternative for the VIV control of long-span bridges.
  • Shear behavior of dry and epoxied joints in precast concrete segmental box
           girder bridges under direct shear loading
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Ghafur H. Ahmed, Omar Q. Aziz Precast segmental concrete bridge construction involves multiple concrete elements joint together by post-tensioning. The joints that represent locations of discontinuity are the prominent factors affecting the overall behavior of segmental bridges. In this study, a series of single cell, box shaped specimens, with a geometry closely resembling the keyed joint of actual segments, were subjected to direct shear test. The joints are flat and keyed, dry and epoxied, having web and flange keys. Tests were carried out to assess the shear capacity, shear behavior, crack propagation and deformations of different kinds of joints. It was found that epoxy can minimize joint imperfections and letting shear stresses to be distributed uniformly. Perfect joint closure and shear transfer was observed for epoxied joint when fully posttensioned immediately. Shear capacity of epoxied joints had consistently higher than dry joints by 25–28%; while, the failure of the epoxied joints was found to be sudden and brittle. The average shear transfer of a single key is higher for specimens with less number of keys. Four flange shear keys are capable to increase shear capacity by 14% and the elastic stiffness of the joints by 73%. It was determined that, the AASHTO design criterion can conservatively predict shear capacity of all kinds of epoxied joints and flat dry joints; however, it is greatly overestimating the shear capacity of multi-key dry joints.
  • A simple structural control model for earthquake excited structures
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Arcan Yanik, Unal Aldemir The biggest challenge and criticism on active control systems in earthquake engineering applications point out the issues that could occur because of a possible power loss of the active controller system during an earthquake. The power supply of an active control system can be disabled during an earthquake. This study is written to introduce a simple structural model to overcome the challenges defined above, and to investigate the performance of this system. The integrated active and semi-active control system is named as “INASA.” The proposed control method of the INASA system both minimizes integrated active and semi-active control energy, as well as the structural energies. A building with an active tendon controller system, with the integration of an MR damper, is considered as an example structure. For numerical validation of the INASA system, near-fault and far-fault earthquakes are used. The electrical current need for operation of the MR damper as well as the time-delay effects of the active tendon controllers are also taken into account for more realistic dynamic simulations. The dynamic performance of the INASA system under different earthquakes is compared to the building equipped with the MR damper the conventional uncontrolled structure. The results showed that the INASA system could work without any stability problems under both earthquakes. Time-delays did not have a negative effect on the system. And a reasonable reduction in uncontrolled response is achieved with very small power requirement. In the possible case of a power loss, the deactivation of the active tendon control system did not lead to a discrepancy, because the MR damper continued to operate with a very small power requirement and showed a good performance.
  • Fiber-hinge modeling of engineered cementitious composite flexural members
           under large deformations
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Hasan Tariq, Ezra A. Jampole, Matthew J. Bandelt Engineered cementitious composites (ECC) and other ductile cement-based materials have emerged as alternative materials to traditional concrete to improve the damage resistance, deformation capacity, and energy absorption capacity of structures in seismic applications. Developing computationally efficient numerical models and simulation techniques to predict the nonlinear response of ductile concrete materials can improve the engineering community’s understanding of the performance of structures using these emerging materials. In this study, a numerical modeling strategy was developed, calibrated, and evaluated that can capture the cyclic response of reinforced ECC components under lateral load reversals at high deformations including component failure due to reinforcement fracture. A fiber-based lumped-plasticity model was adopted to simulate the non-linear response of reinforced ECC components. A simple expression for plastic-hinge length was developed to predict the force-deformation response and deformation associated with reinforcement fracture. Inaccuracies in the initial stiffness and cyclic response were mitigated by calibrating the rotational stiffness of an elastic spring and cyclic degradation parameters of a steel material model. The proposed modeling strategy was evaluated on 18 specimens using different cyclic deformation histories and reinforcement ratios. The modeling approach was compared to experimentally determined lateral strength, energy dissipation, deformation capacity, and longitudinal reinforcement strains to assess the accuracy of the strategy. This research provides a method to simulate the performance of ductile cement-based materials under large deformations, including collapse, and will improve the performance-based earthquake engineering analysis techniques for structures using ductile cementitious materials.
  • A comparative analysis of multiaxial fatigue models under random loading
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Ibai Portugal, Mireia Olave, Iker Urresti, Aitor Zurutuza, Arkaitz López, Miguel Muñiz-Calvente, Alfonso Fernández-Canteli A number of structural components, such as those related to wind turbines, are permanently subject to randomly varying load conditions during their service life and are therefore exposed to fatigue failure hazards. For this reason, the use of models for lifetime prediction is indispensable to ensure the structural integrity of at component and the correct operation conditions during its service life. This article compares different multiaxial fatigue criteria, in order to promote a secure and optimal design. Orthogonal shear stress and critical plane models based on stresses (e.g., McDiarmid and Findley), strains (e.g., Brown-Miller) and energy (e.g., Fatemi-Socie and Smith-Watson-Topper) are therefore considered. With this goal, the effect of randomly distributed load histories is analysed using a novel methodology based on the calculation of the stress tensor as a function of time, by interpolating loads with those obtained from response surfaces using Finite Element Method (FEM) models. The critical values of the selected parameters involved in the failure criterion, once estimated, are considered as references and used to determine the fatigue damage based on the Wöhler curves of the material. The methodology proposed allows the most suitable multiaxial fatigue criterion to be recognised by comparing predicted and experimental lab fatigue lives and levels of safety reserve. In this way, a methodology is provided to advance in the optimal test fitting and lifetime prediction of components under real fatigue conditions.
  • Theoretical and numerical crush analysis of multi-stage nested aluminium
           alloy tubular structures under axial impact loading
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): TrongNhan Tran, DucHieu Le, Ahmad Baroutaji In this paper, the crush behaviour and energy absorption performance of nested tubular thin-walled structures made of aluminium alloy AA6061-O under dynamic axial loading are investigated. Theoretical solutions for Average Crush Force (Pacf) of these structures are proposed by combining the energy method, simple superposition principle, and interaction among the various components of the structures. The derived theoretical models are verified by comparing their predictions with numerical and experimental values. The energy absorption indicators of the various structures are calculated and used to compare the various structures and to determine the best performing one. It is found that the nested structure with a higher number of tubes exhibits the best crashworthiness performance due to energy absorption enhancements resulted from the interaction effects between its components as well as its capability to reduce the peak crush force.
  • Static and fatigue push-out tests of short headed shear studs embedded in
           Engineered Cementitious Composites (ECC)
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Yiming Liu, Qinghua Zhang, Yi Bao, Yizhi Bu Engineered Cementitious Composites (ECC) is a family of high-performance fiber-reinforced cementitious composites with high tensile ductility and emerging in steel-concrete composite structures. In the composite structures, shear force transfer through shear connectors plays a critical role to integrate the steel and concrete. This study experimentally investigates the static and fatigue behaviors of short studs embedded in ECC through push-out tests of nine specimens. The test results of the shear strength, slip capacity, and fatigue resistance are compared with current design codes. The shear strength agrees well with that obtained from AASHTO LRFD, while the Eurocode 4 and Chinese code underestimate the shear strength. The slip capacity satisfies the ductility requirement in Eurocode 4. Based on the fatigue tests results, an S-N curve related to a survival probability of 95% is proposed. Empirical formulas are derived as a tool to help predict the load-slip behavior of the specimen under fatigue loading.
  • Calculation of the resistance of an unequal span steel substructure
           against progressive collapse based on the component method
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Bao Meng, Weihui Zhong, Jiping Hao, Xiaoyan Song, Zheng Tan The rapid quantitative assessment of a structure’s resistance is critical to the structural design process in order to prevent the occurrence of progressive collapse. In this study, a three-bar component model of a top-seat angle with a double web angle connection was constructed based on the component method by dividing and simplifying its geometry. The proposed component model was then applied to a model of an unequal span substructure. An explicit calculation method and a numerical simulation method were proposed to describe the nonlinear static responses of the unequal span substructure under a scenario of interior column failure. These two methods were carefully validated against previously collected experimental data and were determined to accurately reflect the main responses of the structure, including the load–displacement relationship, development of internal forces, and deformation behaviour. The explicit calculation procedure, conducted using a step-by-step process in an Excel spreadsheet, was successfully applied to rapidly analyse and quantitatively evaluate the resistance of the unequal span steel substructure, which will lay the foundation for the resistance prediction and performance analysis of the whole structure against progressive collapse.
  • Cyclic loading test for interior precast SRC beam-column joints with and
           without slab
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Qin Gao, Jun-Hua Li, Zhe-Jun Qiu, Hyeon-Jong Hwang For better constructability, precast joint segments are used in Steel Reinforced Concrete (SRC) beam-column joints. In this study, quasi-static cyclic tests were performed on six precast SRC beam-column joint specimens with or without slab and one monolithic joint specimen with slab to investigate the load-carrying capacity, deformation capacity, failure mode, stiffness degradation, and energy dissipation capacity. For the test parameters, three connection types of weld-connection, high strength bolt-connection, and a combination of weld- and high strength bolt-connections were considered. The connection location was kept away from the column face so as to avoid the inherent plastic hinge at the connection. The test results showed that the precast SRC beam-column joints with slab exhibited better seismic performance than that of the precast joints without slab. The plastic hinge occurred in steel beam brackets without connection failure. The peak strength was not decreased by bolt-slip at the connection in the joint specimen without slab, while bolt-slip decreased the peak strength of the joint specimen with slab. This study results give an insight to structural engineers for design of precast SRC beam-column joints.
  • Theoretical and experimental investigation on the nonlinear vibration
           behavior of Z-shaped folded plates with inner resonance
    • Abstract: Publication date: 1 March 2019Source: Engineering Structures, Volume 182Author(s): Xiangying Guo, Yang Zhang, Wei Zhang, Lin Sun As one of the classical complex multibody structures, Z-shaped folded plates are widely applied in several engineering structures. In the present paper, the nonlinear vibration characteristics of a Z-shaped folded plate composed of three carbon-fiber composite plates were analyzed through theoretical and experimental investigation. The nonlinear dynamic model of the Z-shaped plate was developed based on the Hamilton principle, von Kármán equations, and the classical laminate plate theory, and the vibration mode shape functions of the system were calculated in ANSYS. Further, the Galerkin approach was employed to discretize the partial differential equations into a two-degrees-of-freedom nonlinear system, and the effects of transverse excitations on the nonlinear dynamic behavior of the Z-shaped folded plate were investigated through a comprehensive numerical simulation. Moreover, the obtained theoretical results were verified by experimental analysis. In addition, the vibration mode shapes of the Z-shaped folded plate were obtained by operational modal analysis (OMA). The modal parameters were first identified successfully using the PolyMAX method and then validated by modal assurance criterion (MAC). Finally, an excitation-measurement test was designed to measure the nonlinear vibration characteristics of the Z-shaped folded plate.
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