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  Subjects -> ENGINEERING (Total: 2272 journals)
    - CHEMICAL ENGINEERING (190 journals)
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CIVIL ENGINEERING (183 journals)                     

Showing 1 - 183 of 183 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 17)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 34)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 28)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 30)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 1)
Archives of Civil Engineering     Open Access   (Followers: 10)
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: 6)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 9)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 15)
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: 12)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 17)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 2)
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: 7)
Civil And Environmental Engineering Reports     Open Access   (Followers: 5)
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: 17)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 9)
Civil Engineering Dimension     Open Access   (Followers: 8)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 266)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 36)
Concrete Research Letters     Open Access   (Followers: 6)
Construction Economics and Building     Open Access   (Followers: 2)
Construction Engineering     Open Access   (Followers: 8)
Construction Management and Economics     Hybrid Journal   (Followers: 22)
Construction Science     Open Access   (Followers: 4)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 2)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 16)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 14)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 8)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 16)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 4)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 3)
Géotechnique Letters     Hybrid Journal   (Followers: 6)
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Hybrid Journal   (Followers: 2)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 22)
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: 16)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 1)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 13)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 8)
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: 5)
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: 10)
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: 4)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 6)
International Journal Sustainable Construction & Design     Open Access  
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal   (Followers: 1)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 11)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 7)
Journal of Civil Engineering Research     Open Access   (Followers: 6)
Journal of Civil Society     Hybrid Journal   (Followers: 4)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 24)
Journal of Construction Engineering     Open Access   (Followers: 7)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 8)
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: 11)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 13)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 21)
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: 5)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 11)
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 3)
Journal of Solid Waste Technology and Management     Full-text available via subscription   (Followers: 1)
Journal of Structural Engineering     Full-text available via subscription   (Followers: 40)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 3)
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  
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
Jurnal Spektran     Open Access   (Followers: 1)
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)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 17)
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 6)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 7)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 4)
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 10)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 6)
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: 4)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 9)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 9)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 23)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 13)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 8)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 6)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 6)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 2)
Thin-Walled Structures     Hybrid Journal   (Followers: 4)
Transactions of the VŠB - Technical University of Ostrava. Construction Series     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Underground Space     Open Access  
Water Science & Technology     Partially Free   (Followers: 25)
Water Science and Technology : Water Supply     Partially Free   (Followers: 22)


Journal Cover Engineering Structures
  [SJR: 1.813]   [H-I: 83]   [13 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0141-0296
   Published by Elsevier Homepage  [3051 journals]
  • Monitoring based nonlinear system modeling of bridge–continuous
           welded rail interaction
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Alfred Strauss, Saeed Karimi, Martina Šomodíková, David Lehký, Drahomír Novák, Dan M. Frangopol, Konrad Bergmeister
      The investigation of longitudinal loads and their influence on stresses and internal forces in continuous welded rails (CWR) connected to bridge deck has been discussed intensively in the last 20 years. These discussions originated from the 1995 UIC-recommendation 774-3R, and led to the introduction of the Eurocode 1. These standards are very conservative. For instance, the code used a bi-linear stiffness–displacement law for the validation of the rail–bridge structure interaction and its effects on the rail stresses lead for short bridge spans to rail interruptions. The objective of this paper is to formulate the capacities and boundary conditions of the rail–structure interaction by means of extended numerical linear and nonlinear analyses, which are not fully comprehended in the standard specifications and therefore result in conservative interaction laws. The analyses have been carried out by means of monitoring-based nonlinear finite element modeling using advanced beam–spring interaction laws and specified thermomechanical considerations for capturing the real thermal expansion of bridge structures.

      PubDate: 2017-11-16T16:18:12Z
  • A weak shear web model for deflection analysis of deep composite box-type
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): S.R. Atashipour, U.A. Girhammar, N. Challamel
      Deep box-type beams, consisting of framing members and sheathings, are sensitive to shear deformations and hence appropriate refined theories or complicated magnification factors are needed to be used to obtain accurate results. For sheathings or webs between the framing members that are weak in shear, additional shear deformations occur corresponding to the relative axial displacement between the framing members. These sandwich-type or partial interaction-type of in-plane shear behaviour between the framing members, needs to be taken into account, especially when the web shear stiffness is very low. The composite box-type beam treated here is composed of three framing members with sheathings on both sides. To incorporate effects of the sheathings shear deformations between the framing members on the deflection, the sheathings, here called web interlayers, are modelled as shear media with equivalent slip moduli corresponding to a partially interacting composite beam model. Governing equilibrium equations of the model are obtained using the minimum total potential energy principle and solved explicitly. The obtained results are compared with those based on different conventional beam theories and 3-D finite element (FE) simulations. It is shown that the model is capable of predicting accurately the deflection for a wide range of geometry and property parameters. It is demonstrated that the deflection of such deep box-type beams can be expressed as the summation of three different effects, namely bending deformations, conventional shear deformations in the framing members and sheathings, and additional in-plane shear deformations or shear slips of the weak web causing relative axial displacements between the framing members.

      PubDate: 2017-11-16T16:18:12Z
  • Experimental research and finite element analysis on seismic behavior of
           CFRP-strengthened seismic-damaged composite steel-concrete frame columns
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Sheng Peng, Chengxiang Xu, Mengxiao Lu, Jianming Yang
      Four composite steel–concrete frame columns were constructed to investigate the seismic performance of seismic-damaged composite steel–concrete frame columns strengthened with carbon fiber reinforced polymer. The test consisted of pre-damage loading, rehabilitation with carbon fiber reinforced polymer and destruction tests under lateral cyclic loading. The effectiveness of strengthening seismic-damaged columns with carbon fiber reinforced polymer and the strengthening effect on different degrees of seismic damage were studied. Also, based on the test data, various parameters were obtained, including the hysteretic loops, skeleton curves, axial compression ratio, number of pasted layers of carbon fiber reinforced polymer, ductility, dissipative ability, ultimate strength, stiffness degradation, etc. The results revealed that the failure mode of all the columns was bending failure. The study indicates that the rehabilitated columns can reach or even exceed the level of their original seismic performance before seismic damage up to a certain extent of damage level. Composite steel–concrete frame columns strengthened with carbon fiber reinforced polymer sheets were simulated using the finite element analysis software ABAQUS. The comparison of the results of the conducted analytical study with the experimental results revealed that they are basically consistent with each other.

      PubDate: 2017-11-16T16:18:12Z
  • Seismic fragility analysis of deteriorating RC bridge substructures
           subject to marine chloride-induced corrosion
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Fengkun Cui, Haonan Zhang, Michel Ghosn, Yue Xu
      This paper presents an improved reinforced concrete steel bar deterioration model that incorporates pitting corrosion and considers the change in after-cracking corrosion rate to assess the time-dependent seismic fragility of RC bridge substructures in marine environments. The proposed deterioration model is applicable for both existing and new RC bridge substructures and could be employed for life-cycle analysis of RC bridge substructures in marine environments. In this paper, the model is implemented to conduct a probabilistic seismic fragility analysis of a three-span continuous box girder bridge accounting for uncertainties in establishing bridge geometry, material properties, ground motion and corrosion parameters. Differences in the results obtained when reinforcing steel is subjected to general and pitting corrosion are investigated. The results show that the effect of chloride-induced corrosion cannot be neglected when performing the seismic fragility analysis of RC bridge substructures in marine environments. Additionally, the calculated time-dependent fragility curves indicate that there is a nonlinear accelerated growth of RC column vulnerability along the service life of highway bridges, especially after twenty-five years of exposure to chlorides.

      PubDate: 2017-11-16T16:18:12Z
  • A composite beam theory for modeling nonlinear shear behavior
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Fang Jiang, Ankit Deo, Wenbin Yu
      Accurate predictions of physically nonlinear elastic behaviors of a material point in the structure are essential to the further analyses which are beyond the linear elasticity regime, for example, the progressive damage and the failure. In light of substantial experimental evidence of nonlinear shear stress-strain responses in composites, it is necessary to consider them in the structure-level simulations rigorously. A variational asymptotic beam model is developed for this purpose. The three-dimensional continuum is rigorously reduced to a two-dimensional cross-sectional analysis and a one-dimensional Euler-Bernoulli beam analysis. The original three-dimensional continuum features material nonlinearities in longitudinal shear. The unknown cross-sectional warping is solved by finite element method using the principle of virtual work. Nonlinear beam constitutive relation and three-dimensional stress and strain fields are obtained.

      PubDate: 2017-11-16T16:18:12Z
  • Metamodel-based design optimization of structural one-way slabs based on
           deep learning neural networks to reduce environmental impact
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Javier Ferreiro-Cabello, Esteban Fraile-Garcia, Eduardo Martinez de Pison Ascacibar, Fco. Javier Martinez de Pison Ascacibar
      This article presents a methodology for the construction and use of metamodels with Deep Learning (DL) methods that are useful for making multi-criteria decisions in the design and optimization of one-way slabs. The main motivation behind this research has been to examine the possibilities of improving slab design by including this methodology in future tools, which is capable of calculating thousands of solutions in real time based on the designer’s specifications. The process of creating these metamodels begins by developing a database of millions of combinations of slab designs. These combinations are calculated with a heuristic algorithm that provides the following results: rigidity, deflection, cost per square meter, CO2 emissions and embodied energy. Once a database including the entire universe of possible solutions has been created, a metamodel is developed that is capable of “condensing” the implicit knowledge contained in the database. This metamodel is included within a Decision Support System (DSS) that produces thousands of solutions for slabs that all comply with a range of specifications designated by the design plan. Furthermore, the methodology described herein proposes the use of Pareto-optimal solutions and graphic tools to help designers make multi-criteria decisions regarding the solutions that best fit their needs. A case study is presented to illustrate this proposal: optimizing slab design in two buildings according to technical, economic and sustainability criteria. The results indicate that the multi-criteria solutions obtained would entail a significant reduction in both emissions and embodied energy as compared to mono-criteria solutions, without significantly increasing costs.

      PubDate: 2017-11-16T16:18:12Z
  • Reduced order modelling of elastomeric vibration isolators in dynamic
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): O. Flodén, G. Sandberg, K. Persson
      Dynamic substructuring is often employed to reduce the size of numerical models for structural dynamic analysis. In this paper, we discuss how elastomeric vibration isolators can be modelled within the framework of dynamic substructuring in order to obtain accurate and efficient reduced order models. For several reasons, it is beneficial to divide a structure containing elastomeric isolators into substructures at the interfaces between elastomers and surrounding parts of the structure. Therefore, we consider the elastomeric isolators as reduced coupling elements in the connections of substructure models. The coupling elements are established by reducing the number of degrees of freedom of 3D finite element models of elastomers. The main purpose of the studies presented in the paper is to evaluate the performance of different reduction method when applied to elastomer models. In addition, the effects of modelling features such as rotational coupling and frequency-dependent material properties of elastomeric isolators are investigated. A model of a wooden building structure with elastomeric isolators is used as an example case, considering steady-state dynamic analysis in the low-frequency range. The results and discussions presented in the paper provide guidance for reduced order modelling of elastomeric isolators in dynamic substructuring.

      PubDate: 2017-11-16T16:18:12Z
  • Test and lower bound modeling of keyed shear connections in RC shear walls
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Jesper Harrild Sørensen, Morten Andersen Herfelt, Linh Cao Hoang, Aurelio Muttoni
      This paper presents an investigation into the ultimate behavior of a recently developed design for keyed shear connections. The influence of the key depth on the failure mode and ductility of the connection has been studied by push-off tests. The tests showed that connections with larger key indentations failed by complete key cut-off. In contrast, connections with smaller key indentations were more prone to suffer local crushing failure at the key corners. The local key corner crushing has an effect on the load-displacement response, which is relatively more ductile. In addition to the tests, the paper also presents lower bound modeling of the load carrying capacity of the connections. The main purpose of the lower bound model is to supplement an already published upper bound model of the same problem and thereby provide a more complete theoretical basis for practical design. The two models display the same overall tendencies although identical results are not possible to obtain, due to differences in the basic assumptions usually made for upper and lower bound analysis of connections. It is found that the test results, consistent with the extremum theorems of plasticity, are all lying within the gap between the upper and the lower bound solution. The obtained results finally lead to a discussion of how the two models can be used in practice. The primary merit of the upper bound model lies in its simplicity (a closed-form equation). On the other hand, the lower bound model provides safe results, but is more complicated to apply. It is therefore argued that the upper bound model may be used in cases, where calibration with tests has been carried out. The lower bound model should be applied in situations, where the design deviates significantly from the configurations of the available tests.

      PubDate: 2017-11-16T16:18:12Z
  • Seismic performance of Concentrically Braced Frames with non-buckling
           braces: A comparative study
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Canxing Qiu, Yichen Zhang, Han Li, Bing Qu, Hetao Hou, Li Tian
      Bucking-restrained braces (BRBs) can help limit the maximum transient inter-story drifts of Concentrically Braced Frames (CBFs) under earthquake loading, but they are not effective in mitigating the post-earthquake residual inter-story drifts in the CBFs. Shape Memory Alloys (SMAs) can exhibit flag-shape hysteretic loops with zero or negligible residual deformations under cyclic loading, suggesting their excellent superelasticity and energy dissipation capacity. With the limitation of the conventional BRBs and the favorable feature of the SMAs, it has been questioned that if the SMA braces (SMABs) can be used as alternatives to the conventional BRBs to further reduce the residual inter-story drifts while limiting the maximum transient inter-story drifts in CBFs. Focusing on a six-story demonstration CBF which has representative geometries, the SMABs were designed to enable the demonstration CBF to achieve similar maximum transient inter-story drift responses to the same CBF consisting of the BRBs under the design-level earthquake excitations. Seismic performances of the two designs (with the SMABs and the BRBs, respectively) were investigated through nonlinear static analyses and nonlinear response history analyses based on three suites of ground motion records representing different seismic hazard levels. Analysis results show that the SMABs are as effective as the BRBs in limiting the maximum transient inter-story drifts in the considered CBF but are more effective in reducing the residual inter-story drifts of the CBF. Moreover, it is found that the CBF with the SMABs can achieve a more uniform transient inter-story drift distribution in the system compared with the system consisting of the conventional BRBs. Finally, the advantage of the SMABs over the conventional BRBs is demonstrated through probabilistic analyses and interpretations of the results from the nonlinear response history analyses.

      PubDate: 2017-11-16T16:18:12Z
  • Condition assessment of cables by pattern recognition of vehicle-induced
           cable tension ratio
    • Abstract: Publication date: 15 January 2018
      Source:Engineering Structures, Volume 155
      Author(s): Shunlong Li, Shiyin Wei, Yuequan Bao, Hui Li
      The stay cables are one of most critical elements for cable-stayed bridges. This paper proposes a machine-learning based condition assessment method for stay cables by using the monitored cable tension force. First, based on the correlation of cable tension response between cable pairs (defined as the two cables at the upriver side and the opposite downriver side in the double cable planes), cable tension ratio is extracted as the feature variable, and the cable tension ratio is defined as the ratio of vehicle-induced cable tension between a cable pair. It is found that cable tension ratio is only related with cable properties and the transverse position of a vehicle over the deck. Vehicles on the bridge naturally cluster themselves into a few clusters that correspond to the traffic lanes, i.e. the vehicles in one lane form a cluster. Consequently, the vehicle-induced cable tension ratio forms the corresponding clusters or patterns. Gaussian Mixture Model (GMM) is employed for modelling the patterns of cable tension ratio, and each pattern (corresponds to a certain traffic lane) is modelled by a mono-Gaussian distribution. The Gaussian distribution parameters of tension ratio are used as condition indicator of stay cables because they are only related to cable conditions (the information of vehicle transverse location is presented in the number of tension ration patterns). The number of patterns which represents the model complexity are determined by Bayesian Information Criteria (BIC), while other parameters of GMM are estimated by using Expectation-Maximization algorithm under the Maximum Likelihood criteria, based on the monitored cable tension force. The cable condition is then evaluated according to the variation in estimated parameters of GMM. It is noted that pre-process of source separation is conducted to make the cable tension ratio independent from vehicle weight, environmental variant, and possible sensor errors. An FE model analysis is carried out to qualitatively illustrate the principle of the proposed method and physical sense of the cable tension ratio.

      PubDate: 2017-11-09T07:16:56Z
  • Investigation and verification on seismic behavior of precast concrete
           frame piers used in real bridge structures: Experimental and numerical
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Hongya Qu, Tiantian Li, Zhiqiang Wang, Hongyi Wei, Jiawei Shen, Hao Wang
      In this study, quasi-static cyclic test was conducted for three 1/3-scale specimens of different precast concrete frame pier structure systems of an urban viaduct in Shanghai, China. Various connection deployment strategies were utilized for the specimens, in order to verify these precast concrete frame piers used in the real structure. Two of the specimens were of the same cap beam design, while the third one was with tie beam. The two frame piers with cap beam had the same column-footing connection (grouted splice sleeve coupler), but the column-cap connections were grouted splice sleeve coupler and grouted corrugated duct connection, respectively. The frame pier with cast-in-place tie beam, however, only kept the grouted splice sleeve coupler for column-footing connection. The cyclic test results showed similar seismic behavior of the two specimens with cap beam, whereas the specimen with tie beam exhibited less energy dissipation capacity. This indicated that the seismic performance differences among the specimens are mainly caused by different structure systems, and the two types of the connections behave similarly with little damage. Finite element models that were optimized by considering joint region behavior and bond-slip phenomena showed good agreement with the test results.

      PubDate: 2017-11-09T07:16:56Z
  • Simplified method for rapid seismic assessment of older R.C. buildings
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Stylianos I. Pardalopoulos, Stavroula J. Pantazopoulou, Vasilios A. Lekidis
      After several years of progress in earthquake design procedures, existing reinforced concrete buildings that fall short of modern standards still represent the vast majority of the built environment. Poorly reinforced concrete structures are a threat to human life – an undeniable fact witnessed time and again during strong earthquakes throughout the world. Structures fail when subjected to deformation demands greater than their deformation capacity, thereby losing their ability to support the overbearing load. Efforts are focused in the development and simplification of direct assessment procedures that may be used to spot the likely collapse candidates from among the large inventory of existing construction. In this paper, simple procedures by which to estimate seismic demands and seismic capacities are used as a basis for the development of an evaluation flow chart that may be used by site engineers as a guide for field assessment. The demand in terms of peak lateral drift and the value of peak ground acceleration that the structure may support with little damage are expressed in closed form using simple geometric and material characteristics of the structure. The same tools may be used to guide the selection of a pertinent retrofit strategy that would eliminate the formation of a collapse mechanism in the structure. Practical application examples of seismic assessment and evaluation conducted on existing reinforced concrete buildings that suffered different levels of damage during past strong earthquakes are included for illustration.

      PubDate: 2017-11-09T07:16:56Z
  • Modal strength reduction factors for seismic design of steel moment
           resisting frames
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Dimitris G. Loulelis, George A. Papagiannopoulos, Dimitri E. Beskos
      Traditional seismic design of framed structures uses a single constant value for the strength reduction factor. In this work, explicit expressions for different values of strength reduction factors for the first significant modes of steel moment resisting frames including strength deterioration and panel zone effects are developed. These factors are functions of modal periods and deformation/damage and are defined for four performance levels in a performance-based seismic design framework. The above factors are obtained through extensive parametric studies involving 20 steel frames and 100 far-field ground motions and following a two steps procedure: First an equivalent linear structure with the same mass and elastic stiffness of the original non-linear one is constructed based on equivalent modal damping ratios, which substitute the non-linearities; then use of these equivalent modal damping ratios in conjunction with modal damping reduction factors leads to modal strength reduction factors. Using these factors, one can obtain the seismic design base shear of a frame through response spectrum analysis. Thus, a more accurate and rational seismic design method is established. Numerical examples are presented to illustrate the method and demonstrate its advantages against conventional seismic design methods.

      PubDate: 2017-11-09T07:16:56Z
  • Monitoring of the load-induced RC beam structural tension/compression
           stress and damage using piezoelectric transducers
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Demi Ai, Hui Luo, Chao Wang, Hongping Zhu
      Efficacious monitoring the mechanical stress of engineering structures or components holds the key to understanding the occurrence of structural damage in Structural Health Monitoring (SHM) domains. This paper investigated the monitoring of the load-induced structural tension/compression stress and damage using smart Piezoelectric lead Zirconate Titanate (PZT) transducers mounted to specific locus on structures. Structural tension/compression stress was theoretically incorporated into mechanical impedance to formulate a novel one-dimensional PZT-structure dynamic interaction model. Proof-of-concept experimentation was conducted using a reinforced concrete (RC) beam subjected to a four-point bending test till failure, in which tension and compression stress were simultaneously produced at the bottom/top edge of the beam and captured by two mounted PZT transducers. Load-induced structural tension/compression stress and stress-induced damage were qualitatively evaluated through analyzing the characters of electromechanical admittance (EMA) signatures and comparing to that of the non-stressed PZT transducer. Quantification assessment of stress and damage using statistical root mean square deviation index were also presented. Test results indicated that the peak variation and frequency shift of EMA signatures responding to tension and compression stress were converse in nature, and their gradual changes provided cogent evidences for predicting the development of stress and damage. Results of this paper can be potentially to help monitor structural stress and discriminate from damages in real-life SHM applications.

      PubDate: 2017-11-09T07:16:56Z
  • Inter shear transfer of unbonded prestressing precast segmental bridge
           column dry joints
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Zhan-Yu Bu, Wei-Ye Wu
      The shear performance of precast segmental bridge column (PSBC) epoxy-free dry joints was investigated. Ten PSBC dry joint specimens were tested under monotonic direct shear loading. The design parameters include sectional shape, with or without shear keys, key number and geometry, and confining stress. The shear resistance-relative vertical displacement curves were recorded. The damage patterns and failure mechanism of tested specimens were analyzed. Shear strength formulas for prismatic, castellated, and flat dry joint were derived through data regression. The applicability of proposed formulas together with those from literature was investigated. Finally a finite element (FE) model was calibrated to study the friction contribution to shear capacity at various confining stresses.

      PubDate: 2017-11-09T07:16:56Z
  • A closed-form solution of the interfacial stresses and strains in steel
           beams strengthened with externally bonded plates using ductile adhesives
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Meng Liu, Mina Dawood
      Ductile adhesives are known to be beneficial in enhancing the capacity and ductility of bonded joints. However, there is a lack of closed-form analytical solutions for plated metallic beams that account for adhesive plasticity. This paper presents a first order, elastic-plastic bond analysis for beams strengthened with externally bonded fiber reinforced polymer (FRP) plates using ductile adhesives, based on a shear-lag formulation. This model is able to analyze arbitrary mechanical and thermal loading conditions and closed-form solutions under shearing and peeling are given. Following a review of the existing stress-based analytical solutions, a comparison between the existing and proposed analyses is also presented. The shear solution was validated by comparing with the experimental results of carbon fiber reinforced polymer (CFRP) strengthened steel beams under moderately elevated temperatures. A comprehensive parametric study has been conducted to illustrate the effects of different design parameters on the bond behavior. It is found that the adhesive shear toughness is the most critical parameter in determining the debonding failure load while the adhesive Young’s modulus does not significantly affect the bond stresses in the elastic-plastic regime. Further, the magnitude of the peak peeling stresses is self-limiting after shear yielding, and the use of a thinner plate with higher Young’s modulus is beneficial in further reducing the peeling stress.

      PubDate: 2017-11-09T07:16:56Z
  • Biaxial shear behaviour of HDNR with Mullins effect and
           deformation-induced anisotropy
    • Abstract: Publication date: 1 January 2018
      Source:Engineering Structures, Volume 154
      Author(s): Laura Ragni, Enrico Tubaldi, Andrea Dall'Asta, Hamid Ahmadi, Alan Muhr
      High damping natural rubber (HDNR) bearings, commonly employed to isolate structures, are subjected to biaxial horizontal deformations by the seismic motion. If they have virgin material properties, biaxial models including the stress softening due to the Mullins effect should be used for describing their force–deformation behaviour. Specific studies oriented at characterizing and modelling the biaxial behaviour of HDNR bearings accounting for the stress-softening are very few in number because they would require a large number of virgin isolators or long times of rest between two consecutive tests. Moreover, available studies consider the Mullins effect as an isotropic phenomenon, whereas experimental investigations have shown that it is direction-dependent and thus induces anisotropy of the rubber behaviour. This paper describes an extensive experimental campaign carried out on a large number of small material test pieces aimed at achieving a satisfactory characterization of the biaxial anisotropic response of a highly dissipative rubber compound. These results are then used to develop a two-dimensional constitutive model for the virgin HDNR material accounting for the direction-dependence of the Mullins effect, based on the concept of representative directions applied to the biaxial shear deformation state. Because for commonly employed laminated HDNR bearings under design actions the approximation of uniform simple shear is realistic, the proposed material model can also be used to simulate the global bidirectional horizontal response of the bearings.

      PubDate: 2017-11-09T07:16:56Z
  • Uncertainty quantification of creep in concrete by Taylor expansion
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): P. Criel, N. Reybrouck, R. Caspeele, S. Matthys
      If deterministic creep prediction models are compared with actual measurement data, often significant differences can be observed. These inconsistencies are associated with different causes, i.e. model uncertainty, uncertain input parameters, measurement errors and wrongfully applying creep prediction models outside their limitations. First, the physical mechanism causing creep of concrete is not yet fully understood. Therefore, it is very likely that certain influences on creep of concrete are not considered in these prediction models, resulting in systematic model errors. The model errors can be quantified by comparing prediction results with experimental data. Secondly, the stochastic character of the input parameters form an additional source of uncertainty which can be quantified by the variance of the model response. The coefficient of variation in function of time-duration, i.e. the time since the application of the load, is a useful measure to quantify the level of uncertainty. In the literature, statistical analysis by means of numerical simulations are often used for this matter. However, even for specialized sampling techniques, a large amount of samples is necessary to cover the relevant ranges of various input parameters. The aim of the present study is to provide an approximate uncertainty quantification of the creep prediction models given uncertain input parameters. This approximation is based on a Taylor series approach. This approach has the advantage that is does not require numerical simulations nor does it require the knowledge of the probability density function of the input parameters. This method is evaluated and compared with the statistical analysis for several creep prediction models available in literature and design codes.

      PubDate: 2017-11-09T07:16:56Z
  • The behaviour of jointed large-diameter reinforced concrete pipeline
           buried in various ground conditions
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Ming Xu, Dawei Shen, Dehai Jin
      Both centrifuge test and three-dimensional numerical simulation were performed to investigate the behaviour of a 1400-mm-diameter reinforced concrete pipeline with gasketed bell-and-spigot joints that was buried in various ground conditions under surface load. Centrifuge test was performed first to study the response of a pipeline placed on silt soil. Numerical simulation was then carried out using a nonlinear elastic-plastic model to represent the soils, with parameters being back-analysed from direct shear tests, which was found to be capable of producing reasonable predictions when compared with the centrifuge test results. Further simulation revealed that the native soil stiffness had a dominant influence on the joint behaviour compared with the backfill stiffness. For the same trench dimensions, increasing the foundation thickness was less effective at reducing the joint rotation than increasing the cover depth. Furthermore, as long as the native soil below the pipeline was uniform, the joint rotation was small, even though the native soil was soft. However, the existence of voids due to soil erosion under the joint had a significant impact on the pipeline performance and could cause a large joint rotation.

      PubDate: 2017-11-09T07:16:56Z
  • Finite element modelling of pre-stressed concrete poles under downbursts
           and tornadoes
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Ahmed M. Ibrahim, Ashraf A. El Damatty, Ayman M. El Ansary
      Among different types of electrical transmission line structures, pre-stressed concrete transmission poles have the advantages of low installation and maintenance cost, appropriate delivery time, and high corrosion resistivity. Typically, these concrete poles are designed to resist only synoptic wind loading as current codes do not consider high intensity wind events in the form of downbursts and tornadoes. To the best of the authors’ knowledge, this study is the first investigation to assess the behaviour of pre-stressed concrete poles under High intensity wind events. Due to the localized nature of those events, identifying the critical locations and parameters leading to peak forces on the poles is a challenging task. To overcome this challenge, a built in-house numerical model is developed incorporating the following: (1) a three-dimensional downburst and tornado wind field previously developed and validated using computational fluid dynamics simulations; (2) A computationally efficient analytical technique previously developed and validated to predict the non-linear behaviour of the conductors under non-uniform loads resulting from those events (3) a non-linear finite element model developed in the current study to simulate the structural behaviour of pre-stressed concrete poles considering material nonlinearity. The non-linear finite element model, is validated using experimental data available in the literature. Extensive parametric studies are conducted using the numerical model to determine the critical downburst and tornado configurations leading to peak overturning moment acting on a pole which is designed to remain un-cracked under synoptic wind load. Failure studies are then conducted to assess the downburst and tornado velocities that would lead to a full collapse of the pole.

      PubDate: 2017-11-09T07:16:56Z
  • Seismic response of liquid-containing tanks with emphasis on the
           hydrodynamic response and near-fault phenomena
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Marina E. Kalogerakou, Charilaos A. Maniatakis, Constantine C. Spyrakos, Prodromos N. Psarropoulos
      The present research studies the hydrodynamic response of cylindrical liquid-containing tanks with stiff walls under seismic excitations. Starting from standard hydrodynamic assumptions, the fluid oscillatory modes are separated to an impulsive mode and convective modes through the introduction of a reference frame co-moving with the base of the tank. The response of the fluid’s normal modes to a lateral excitation and the role of Housner’s oscillators is elucidated. Fast Fourier Transform techniques are applied to samples of earthquake records with near- and far-fault characteristics that have been appropriately scaled to match the Eurocode 8 design spectrum. Critical response quantities including the base shear and the height of the sloshing wave are computed analytically as functions of time and results are compared for near- and far-fault conditions. Particular emphasis is given on the contribution to the above quantities of the second convective mode which is systematically neglected according to current design practices for liquid-containing tanks. The results suggest that under near-fault conditions, when the directivity pulse has substantial content near the frequency of the second convective mode, current provisions may lead to a significant underestimation of the maximum height of the sloshing wave. This observation may provide an explanation of the extensive post-earthquake damage observed at many tank roofs located in the proximity of active faults. The results for near-fault records are compared with those obtained from a simplified representation of the velocity pulse proposed in the literature. The simplified wavelet leads to acceptable accuracy compared with a corresponding real record when the maximum height of the sloshing wave is examined; however, significant underestimation is detected for the calculation of the base shear.

      PubDate: 2017-11-09T07:16:56Z
  • Outrigger tuned inertial mass electromagnetic transducers for high-rise
           buildings subject to long period earthquakes
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Takehiko Asai, Yuta Watanabe
      This paper proposes outrigger tuned inertial mass electromagnetic transducer (TIMET) systems for high-rise buildings subject to long period earthquake excitations. The proposed outrigger TIMET systems consist of the outrigger and TIMET parts. The outrigger damping systems have been proposed as a novel energy dissipation approach to high-rise buildings, in which control devices are installed vertically between the outrigger and perimeter columns to achieve large energy dissipation. While the TIMET has been developed based on the mechanism of the tuned viscous mass damper (TVMD) which can improve energy absorbing capability by taking advantage of resonance effect. However, instead of a viscous material, the damping of the TIMET is provided by a motor which can convert mechanical energy to electrical energy. The focus of this study is to investigate the structural control performance and energy harvesting efficiency of the proposed outrigger TIMET system for high-rise buildings subjected to long period earthquakes through numerical simulations.

      PubDate: 2017-11-09T07:16:56Z
  • Identification of key design parameters for earthquake resistance of
           reinforced concrete shell structures
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Tim Michiels, Sigrid Adriaenssens
      Concrete roof shells have shown to be inherently able to sustain earthquakes, but the reasons for this apparent seismic resistance have been subject to limited research. Concrete shells exhibit a high structural efficiency and thus can be constructed very thin. Because of their relative lightweight nature, the earthquake forces induced in a thin shell structure are relatively low. However, the shape of a shell structure is typically established so that it performs optimally under gravity loads, carrying the loads to the foundations mainly through membrane action over the shell surface. Unanticipated horizontal forces induced by earthquakes generate bending stresses in concrete shell structures, which could lead to structural damage. Through a parametric study of 8 cm thick, concrete roof shells with a square plan, the research presented in this paper demonstrates that small to mid-sized (span<15 m) thin concrete roof shells can indeed be intrinsically earthquake resistant. They owe this resistance to their great geometric stiffness and low mass, which lead to high fundamental frequencies that are well above the driving frequencies of realistic seismic actions. Due to these characteristics the shells analyzed in this paper behave elastically under the earthquake excitation, without surpassing the maximum allowable concrete strength. For shallow shells it is observed that the vertical components of the earthquake vibrations, can induce larger stresses in the shell than the horizontal components. It is further demonstrated that by increasing the rise and curvature of larger shells (20 m by 20 m), their fundamental frequencies are increased and the damaging effect of the vertical earthquake vibration components mitigated.

      PubDate: 2017-11-09T07:16:56Z
  • Railway bridge damage detection using vehicle-based inertial measurements
           and apparent profile
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Paraic Quirke, Cathal Bowe, Eugene J. OBrien, Daniel Cantero, Pablo Antolin, Jose Maria Goicolea
      The presence of damage in a railway bridge alters its stiffness and consequently, its static and dynamic response to loading. The dynamic response of a railway bridge to loading produces a dynamic response in the passing vehicle, potentially enabling detection of the damage through analysis of the vehicle response. A method is proposed in this paper for the detection of bridge damage through comparison of apparent profiles sensed by the passing vehicle. The apparent profile is a virtual longitudinal profile which, when applied to a vehicle, invokes the same measured response to the crossing of a bridge. A change in the deflection of the bridge due to the presence of damage manifests itself as a change in the apparent profile associated with the measured vehicle response. The Cross Entropy optimisation method is used in this study to determine the apparent profiles that generate a vehicle dynamic response most similar to that of a measured input. ‘Measured’ bogie vertical acceleration signals are generated using a 3-dimensional train-bridge interaction model implemented in Abaqus and used as input to a 2-dimensional algorithm implemented in Matlab. Damage is introduced to the bridge structure by applying a localised reduction in the width of the bottom flange of a bridge beam, simulating the effect of a sudden impact from a vehicle strike. Apparent profiles for a number of damage scenarios are inferred and compared over time to detect damage. The algorithm is also tested for resilience to sensor noise and effectiveness in the presence of track irregularities.

      PubDate: 2017-11-09T07:16:56Z
  • Effect of modulus of elasticity and thickness of the CFRP plate on the
           performance of a novel anchor for structural retrofitting and
           rehabilitation applications
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Faizul M. Mohee, Adil Al-Mayah
      This article presents the effect of the thickness, the modulus of elasticity and the strength of the carbon fibre-reinforced-polymer (CFRP) plate on the CFRP-metal couples for the structural rehabilitation and retrofitting applications. This article illustrates the development and assessment of a novel prestressing anchor to grip the commercially available 50 mm × 1.4 mm CFRP plates. This is a high-modulus CFRP plate with a modulus of elasticity of 210,000 MPa and an ultimate tensile strength of 2900 MPa. The new anchor was made of 22-gauge (0.71 mm thick) annealed copper and heat-treated H13 steel. An ABAQUS-based finite element advanced simulation model of the bolted anchor was developed to analyze, optimize and design the new anchor. A detailed manufacturability study was conducted. An experimental investigation was carried out to authenticate the numerical simulation results. The average failure load of this new anchor was 231 ± 6 kN, which was more than 100% of the guaranteed ultimate tensile strength of the high-modulus CFRP plate (203 kN). The failure mode was the sudden tensile failure of the CFRP plate outside of the anchor.

      PubDate: 2017-11-01T00:29:13Z
  • Statistical pattern recognition approach for long-time monitoring of the
           G.Meazza stadium by means of AR models and PCA
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Alessio Datteo, Francescantonio Lucà, Giorgio Busca
      In recent years, the interest for the automatic evaluation of the state of civil structures is increased. The development of Structural Health Monitoring is allowed by the low costs of the hardware and the improving of the computational capacity of computers that can analyze considerable amount of data in short time. A Structural Health Monitoring (SHM) system should continuously monitor structures, extracting and processing relevant information, to efficiently allocate the resources for maintenance and ensure the security of the structure. Considering the latest developments in this field, great attention has been paid to data-based approaches, especially to autoregressive models; these econometric models, born in the field of finance, are usually used to analyze the vibration time series provided by the sensors applied on the monitored structures. Indexes based on these autoregressive models can be used as features by which the structural integrity can be assessed. This work proposes the application of a multivariable analysis, Principal Component Analysis (PCA), to the set of the autoregressive model parameters estimated on the vibration responses of a real structure under operational conditions. This approach reduces a complex set of data to a lower dimension, by representing the behavior of the structure through the few variables. This work uses the principal components of the autoregressive model parameters as indicators that can effectively describe different operational levels and some important environmental effects. The strategy is applied for the first time on the data collected by the long-time monitoring system installed on the stands of the G. Meazza stadium in Milan. The results will show that this procedure is effective in representing the status of the structure and can be used in a structural health monitoring prospective.

      PubDate: 2017-11-01T00:29:13Z
  • Design and analysis of an industrial steel building. Limit states,
           stability check
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): M. Cacho-Pérez
      This work is focused on the design of a structural steel industrial building of double-T type section located in an industrial area of Valladolid (Spain). Firstly, a linear analysis is carried out to dimension the structure and check that it resists according to the established regulations, the Technical Building Code (CTE), the national adaptation of the Eurocodes (ECs). For the analysis of the structure, the 3D model of slender bar bending (Navier-Bernoulli bending theory) and the non-uniform twist or constrained warping model (Vlasov’s torsion theory) are considered. In the second place, a nonlinear analysis is performed with the objective of verifying the Ultimate Limit State of stability of the structural elements and of the industrial building as a whole. All this without the need to estimate buckling coefficients of each of the beams that make up the structure, and without the need for important simplifications. Finally, a linear analysis is once more performed to check the Service Limit State for the frequent combination of actions. The solution of the problem results from an iterative process of searching for the best solution, that is, the one that, with the least amount of steel used, fulfills all the requirements: resistance, stability and displacement limits established by the current regulation.

      PubDate: 2017-11-01T00:29:13Z
  • Behaviors and design method for distortional buckling of thin-walled
           irregular-shaped aluminum alloy struts under axial compression
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Yicun Chang, Mei Liu, Peijun Wang, Xiulin Li
      Since an aluminum alloy structural component can be manufactured through extrusion technology, the cross section can easily comprise various longitudinal stiffeners to strengthen the thin wall and to hold the partition wall panel. In this paper, experimental and numerical investigations on distortional buckling behaviors of thin-walled irregular-shaped aluminum alloy stub columns under axial compression were carried out. Initial geometric imperfections of six extruded aluminum alloy columns were measured using LVDT. The ultimate strength, failure deformation, out-of-plane displacement and strain development of six test specimens were recorded and used to verify a Finite Element Model (FEM) developed by the finite element software ABAQUS. The open plates in the irregular-shaped section had low distortional buckling resistance, which causes the premature failure of the studied columns. 117 columns with different length and plate thickness were numerically simulated by the verified FEM to reveal the influences of plate thickness on column distortional buckling behaviors. The Direct strength method (DSM) was applied and it was essential to determine column distortional buckling stress before performing DSM to calculate column ultimate strength. A modified calculation method for distortional buckling stress of the irregular-shaped aluminum alloy columns was proposed. Distortional buckling stresses of 81 aluminum alloy columns with different plate thickness were analyzed by the FEM to evaluate the modified calculation method. It was accurate and more efficient to use the modified calculation method to calculate distortional buckling stress of the irregular-shaped aluminum alloy columns in DSM.

      PubDate: 2017-10-25T11:21:15Z
  • An experimentally validated finite element formulation for modeling 3D
           rotational energy harvesters
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): J.M. Ramírez, C.D. Gatti, S.P. Machado, M. Febbo
      Piezoelectric energy harvesting devices convert mechanical energy into electrical energy due to the mechanical deformations of the structures. Energy harvesting prototypes are used to feed low-power electronic devices and sensors. In this work, a one-dimensional finite element is developed for modeling three-dimensional rotational energy harvesters. The rotating piezoelectric beam is formulated by means of a geometrically nonlinear finite element with six mechanical degrees of freedom and one electrical degree of freedom per node. Using Timoshenko beam theory for the mechanical domain and a first-order theory for the electrical field, the electromechanical equilibrium equations of motion are then derived using D’Alembert principle. In order to validate our finite element formulation, two energy harvesting devices are built and tested, getting insights into the generation of electrical power, natural frequencies and time responses of the dynamical variables. An Arduino board is implemented as the data acquisition system that transfers the voltage signal via Bluetooth, avoiding the complexity of slip-rings mechanisms for data transmission. Finally, the results of our formulation are compared with those obtained using a commercial software (Abaqus) and the experimental results. A good correlation between the three methods is obtained, providing evidence that our formulation accurately predicts the behavior of rotational energy harvesters.

      PubDate: 2017-10-25T11:21:15Z
  • Modeling seismic response of a full-scale cold-formed steel-framed
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Jiazhen Leng, Kara D. Peterman, Guanbo Bian, Stephen G. Buonopane, Benjamin W. Schafer
      The objective of this paper is to present finite element modeling protocols and validation studies for the seismic response of a two-story cold-formed steel-framed building with oriented strand board sheathed shear walls. Recently, shake table testing of this building was completed by the authors. The building provides an archetype for modern details of cold-formed steel construction, and provides benchmarks for the seismic response of the building system, subsystem, and components. The seismic response of buildings framed from cold-formed steel has seen little study in comparison with efforts on isolated members and shear walls. Validated building-scale models are needed to expand our understanding of the seismic response of these systems. Finite element models corresponding to the archetype building during its various test phases are developed in OpenSees and detailed herein. For cold-formed steel framed buildings accurate seismic models require consideration of components beyond the isolated shear walls, e.g. the stiffness and capacity of the gravity framing is included in the model. Such decisions require model refinement beyond what is typically performed and details for completing this effort accurately and efficiently are described herein. In addition, nonstructural components, including exterior sheathing of the gravity framing, interior gypsum sheathing for the shear walls and gravity framing, and interior partition walls, are included in the building model based on nonlinear surrogate models that utilize experimental characterization of member-fastener-sheathing response. Comparisons between the developed models and testing for natural period, story drift, accelerations, and foundation hold-down forces validate the model. Performance of the tested archetype building is better than predicted by design or typical engineering assumptions. The model developed herein provides insights into how the building achieves its beneficial performance and will be used to further quantify the lateral resistance of each subsystem and the extent of their coupling. In addition, the protocols used to develop the model herein provide a first examination of the necessary modeling characteristics for wider archetype studies of cold-formed steel-framed buildings and the development and substantiation of seismic response modification coefficients.

      PubDate: 2017-10-25T11:21:15Z
  • Analysis of thin-walled steel beams retrofitted by bonding GFRP
           stiffeners: Numerical model and investigation of design parameters
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Tuna Ulger, Ayman M. Okeil
      Enhancing the load capacity of aged and deficient thin-walled steel structures can be accomplished by increasing member stiffness in buckling prone regions. The literature shows that composite materials have become a major player in retrofitting applications. A new strengthening concept, Strengthening-by-Stiffening (SBS), is applied to buckling prone web panels in thin walled steel beams by bonding pultruded glass fiber reinforced polymer (GFRP) sections. The first part of present study is focused on the construction of a finite element (FE) model for accurate simulation of experimentally obtained results. Initial imperfections, material non-linearity, interlaminar fracture law to simulate adhesive debonding, and GFRP rupture or delamination are accounted for in the construction of the FE model. The second part of the study was focused on parametric studies using the validated FE model to investigate different GFRP sizes, contact areas, panel aspect ratio and slenderness of the web panels on steel beam with SBS retrofitting. Results from the parametric study were used to establish some limits to assist in SBS design. Finally, possible use of SBS strengthening method in new construction was investigated by substituting all steel stiffeners with bonded composite GFRP stiffeners for the improvement of fatigue related behavior that is known to start at the weld toes of steel stiffeners.

      PubDate: 2017-10-25T11:21:15Z
  • Complete generalization of the Ayrton-Perry formula for beam-column
           buckling problems
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): József Szalai
      The Ayrton-Perry (or Perry-Robertson) formula based stability resistance model (APF) is very popular in steel structural design standards. Although the original version of the model is more than 100 years old, it is still frequently used and continuously researched due to its simplicity and adaptability. The original and most widely accepted version of the APF is valid only for the flexural buckling of compression members yielding the basic formulation of the column buckling curves of several structural design codes. Recently there were more successful attempts for the extension of the APF type resistance model for other buckling modes such as torsional buckling or lateral-torsional buckling. The paper continues this research by deriving a complete closed-form universal APF type solution for steel beam-column stability problems. Rigorous mathematical solution is given for the so-called “fundamental case” which is defined by a simply supported prismatic beam-column with arbitrary cross-section subjected to uniform compression and biaxial bending. The exact interpretation and the universal form of the member slenderness, imperfection and reduction factors are presented for all possible buckling cases. The results of the paper can widen significantly the field of applicability of APF based design methods providing a theoretically consistent physical model for the beam-column stability problems.

      PubDate: 2017-10-25T11:21:15Z
  • An experimental investigation on dynamic response of composite panels
           subjected to hydroelastic impact loading at constant velocities
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): O.H. Hassoon, M. Tarfaoui, A. El Malki Alaoui
      Generally, when marine vessels encounter the water surface on entry and subsequently re-enter the water at high speed, this can subject the bottom section of the vessels to high hydrodynamic loads, especially over very short durations. This phenomenon generates high hydrodynamic loads, which can cause a catastrophic failure in the structure. In contrast, the interaction between deformable structures and free water surface can be modified the fluid flow and changed the estimated hydrodynamic loads comparing with rigid body, due to appearance of hydroelastic effects. These effects are considered active challenge areas in structural ship design. This work presents an experimental study of the water impact for composite laminate wedge at different constant entry velocities. The aim of this study is to investigate the dynamic structural response of panels and predicts the hydrodynamic loads to meet the specific requirements of marine vessels. In order to better describe hydroelastic influence, two composite panels with different thicknesses namely 8 mm and 13 mm are subjected under constant impact velocities of 4, 6 and 8 m/s with the deadrise angle of 10°. The obtained experimental results were indicated that more flexible panels had a higher peak force and significant dynamic noise compared with higher stiffness panels. In addition, the maximum deformation occurred in the centre and close to the chine edge of the panel due to changes in local velocity and local deadrise angle. For this reason, special attention requires in both design phase and operation phase.
      Graphical abstract image

      PubDate: 2017-10-25T11:21:15Z
  • An integrated Terrestrial Laser Scanner (TLS), Deviation Analysis (DA) and
           Finite Element (FE) approach for health assessment of historical
           structures. A minaret case study
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Mustafa Korumaz, Michele Betti, Alessandro Conti, Grazia Tucci, Gianni Bartoli, Valentina Bonora, Armağan Güleç Korumaz, Lidia Fiorini
      This paper presents a multi-disciplinary approach for identification of historic buildings structural health with combination of Terrestrial Laser Scanning (TLS) survey, Deviation Analysis (DA) and Finite Element (FE) numerical modelling. The proposed methodology was discussed through the application to an illustrative case study: an early medieval period brick minaret (Eğri Minaret) located in Aksaray (central Turkey). After standing upright for several centuries, the minaret has developed tilt, and today the structure is supported with steel cables. Precise direction of inclination, leaning angle, local deviations from circular building shape, deflections from vertical planes, local curvatures and related maps were obtained with high accuracy by DA, based on detailed point cloud 3D mesh model. Differently from traditional approaches in FE analysis, the paper discusses a method for direct transfer of high accuracy TLS based 3D model to FE structural analysis software, subsequently employed to interpret and verify structural health of the historic building. Through the discussion of the results, it can be considered that the integration of these different techniques (being the whole process non-destructive, effective and expeditious for surface analysis) is a promising methodology for health assessment and analysis of historic constructions.

      PubDate: 2017-10-25T11:21:15Z
  • Fiber beam-column model for diagonally reinforced concrete coupling beams
           incorporating shear and reinforcement slip effects
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Ran Ding, Mu-Xuan Tao, Xin Nie, Y.L. Mo
      Due to the improved energy-dissipation and deformation capacity compared to the conventionally reinforced concrete (RC) coupling beams, diagonally RC coupling beams are recommended by the ACI 318 code especially for a span-to-depth ratio of less than two and thus acquire more and more applications in coupled wall and core tube systems for tall buildings. This paper proposes a sufficiently accurate and efficient displacement-based fiber beam-column model for the nonlinear seismic analysis of diagonally RC coupling beams with span-to-depth ratios ranging between one and five. The model is developed on the platform of a general FEA package MSC.Marc. First, the conventional fiber beam-column element is modified to consider the flexural contribution of diagonal bars. Then the new section shear force-shear distortion and slip deformation rules are proposed and incorporated into the modified fiber element, respectively, since both the shear and reinforcement slip are critical mechanisms influencing the seismic performance of the beam. The equations for critical model parameters including the cracked shear stiffness and chord rotation limit are developed and verified based on the results of sixteen test specimens collected from previous research. The model is utilized to simulate the collected specimens together with a coupled wall system and proves to be a powerful tool for the nonlinear seismic analysis of diagonally RC coupling beams and coupled walls with satisfied accuracy, efficiency and modeling convenience.

      PubDate: 2017-10-25T11:21:15Z
  • Finite element model for predicting the shear behavior of FRP-strengthened
           RC members
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Mehdi Zomorodian, Abdeldjelil Belarbi, Ashraf Ayoub
      The shear behavior of FRP strengthened reinforced concrete (FRP strengthened RC) membrane elements can be predicted by developing logical models that satisfy the principles of mechanics of materials namely stress equilibrium, strain compatibility, and constitutive relationships of concrete, steel and, FRP reinforcements. The Softened Membrane Model (SMM), which was developed for predicting the shear behavior of reinforced concrete (RC) membrane elements, is extended to FRP strengthened RC members subjected to shear. This new analytical model, referred to as the Softened Membrane Model for FRP strengthened RC members (SMM-FRP), considers new constitutive laws for each material component of the member. Similar to the case of the SMM model for RC, this new SMM-FRP model can predict the entire stress-strain curve, including pre- and post-cracking, and the ascending and descending branches. The SMM-FRP is implemented into an OpenSees-based finite element program for a membrane 2-D element that will allow structural engineers to predict the monotonic responses of FRP strengthened RC members subjected to shear. The developed program is validated in this paper by the prediction of the monotonic responses of 10 FRP strengthened RC panels subjected to pure shear stresses. The good agreement between the experimental and analytical results confirms the validity of the analytical model in predicting the shear behavior of RC members strengthened with FRP sheets.

      PubDate: 2017-10-25T11:21:15Z
  • Wind forces on circular steel tubular lattice structures with inclined leg
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Yan Li, Zhengliang Li, Bowen Yan, Zhitao Yan
      The wind forces on the steel lattice structures have drawn increasing concerns in the structural design of high-rise and long-span buildings and structures due to their low damping, light self-weight, and high flexibility. The aim of this paper is to assess the aerodynamic forces on circular steel tubular lattice structures with vertical and inclined leg members using the wind tunnel tests. In order to elucidate the underlying mechanism of wind loads contributed by the individual members of lattice structures, a new type of rigid experimental model for High-frequency force balance (HFFB) wind tunnel tests is proposed in the study. And the individual member of lattice structures can be sequentially removed until remaining vertical or inclined leg members, which is referred to as “member subtraction”. The experimental results reveal that with the same solidity ratio, the drag coefficient of lattice structure with inclined leg members is approximately 9% smaller than that with vertical ones. This indicates that the configuration of steel lattice structures, such as inclined leg members, might exert indispensable effects on the drag forces, which has yet been considered in the current wind codes and standards. In addtion, in order to clarify the interference mechanism between the leg and diagonal members, the wind tunnel tests of a three-cylinder model are performed and the wind tunnel results indicate that the presence of diagonal members in lattice structures would increase the overall drag coefficients in the scenario of small separation distances. Finally, the advantages and disadvantages of structural configuration (with and without horizontal or diagonal members) and their implications on structural design are discussed.

      PubDate: 2017-10-25T11:21:15Z
  • Numerical evaluation of the corrosion influence on the cyclic behaviour of
           RC columns
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Fabio Di Carlo, Alberto Meda, Zila Rinaldi
      The corrosion, main cause of degradation in RC structures in non-exceptional conditions, can have also significant effects on the seismic behaviour, leading to dangerous strain localizations and variations of strength distribution and rotation capacity. In this paper, the behaviour of corroded columns under cyclic loads is studied with a three-dimensional Finite Element Analysis, accounting for steel and interface decay and including buckling effects. The model is validated through a comparison with the results of experimental tests developed at the Bergamo University. Finally, a parametric survey is carried out to highlight the main parameters governing the global response.

      PubDate: 2017-10-25T11:21:15Z
  • Strong-axis and weak-axis buckling and local bulging of
           buckling-restrained braces with prismatic core plates
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Wenjing Xu, Chris P. Pantelides
      The performance of new type Buckling-Restrained Braces (BRB) is evaluated. The new type BRB is efficient since the steel core is constructed with prismatic steel plates that are straight throughout its length. Connection plates attaching the BRB to gusset plates are welded perpendicular to the steel core plates; this configuration is different from conventional BRBs in which the core plates also serve as the connection plates. Since the steel core plates are prismatic, construction of new type BRBs saves material and reduces the cost of manufacturing. Four full-scale new type BRBs were tested under quasi-static cyclic loading with either a single core plate or dual core plates using either bolted or welded connections to gusset plates. The hysteresis curves exhibited stable behavior with positive incremental stiffness; the ratio of maximum compression to tension capacity and the cumulative inelastic deformation were satisfactory. There was no rupture or instability and at failure the core plates achieved maximum tensile strains between 3.2% and 4.2%. Failure modes included core plate buckling about the strong or the weak axis and local bulging. The strong and weak axis buckling behavior is modeled using a strut-and-tie model. The local bulging behavior about either the strong or the weak axis is modeled using plastic analysis. Recommendations are presented for preventing strong axis buckling of the steel core and local bulging of the steel casing about the strong axis.

      PubDate: 2017-10-25T11:21:15Z
  • Experimental study of cyclic behavior of high-strength reinforced concrete
           columns with different transverse reinforcement detailing configurations
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Wen-Cheng Liao, Wisena Perceka, Michael Wang
      Detailing of transverse reinforcement is essential to ensure ductile behavior of reinforced concrete (RC) members, particularly for columns with large displacement demanding under high axial loading level. Requirements of reinforcing details are even important for high strength concrete due to its brittleness nature. This paper presents experimental study regarding cyclic behavior of high strength RC columns with different transverse reinforcement detailing layouts. The three high strength RC columns consisted of different transverse reinforcement detailing configurations, which were conventional closed-hoops, butt-welded hoops and single closed-hoop with cross-ties, respectively. The columns were made of high-strength concrete with compressive strength of 70 MPa and high-strength steel with yield stresses of 685 MPa and 785 MPa for longitudinal and transverse reinforcement, respectively. Cyclic displacement static tests subjected to high axial compression loading of 0.3Agf′c were conducted to verify the adequacy of transverse detailing. The performance of the column with conventional closed-hoops and that of the column with butt-welded hoops, which were compliant of ACI 318-14, were almost identical and met the performance criteria required by ACI 374. In contrast, the column with a single closed-hoop and cross-tie that was designed based on ACI 318-11 did not perform well as a ductile RC column. These results prove that the ACI 318-14 minimum requirements for confinement should be followed. In addition, butt-welded hoops are acceptable as a form of transverse reinforcement of a column, since no fracture was observed at the welded location. The current flexural and shear design equations for the RC columns are discussed and compared with the test results.

      PubDate: 2017-10-25T11:21:15Z
  • Time-variant reliability analysis of widened deteriorating prestressed
           concrete bridges considering shrinkage and creep
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Bing Tu, Zhi Fang, You Dong, Dan M. Frangopol
      Nowadays, bridge widening has become an economic option to tackle the increasing demand of the traffic volume and to enhance the capacity of existing highway bridges. Thus, relevant studies on the performance assessment of widened bridges are needed. This paper presents a computational probabilistic framework for time-variant reliability analysis of widened concrete highway bridges in a systematic manner considering the effects of live-load redistribution, structural deterioration, and concrete shrinkage and creep. Specifically, differences and inconsistences between the new and existing structures regarding live-load distribution, reinforcement corrosion, and concrete shrinkage and creep are considered. A finite element grillage model is constructed to investigate live-load distribution factors and internal axial forces caused by concrete shrinkage and creep. The uncertainties associated with shrinkage and creep effects are accounted for within the probabilistic framework. The flexural moment resistance of the bridge girder is computed considering the combined effects of the shrinkage-and-creep-induced axial force and structural deterioration. Ultimately, the system reliability of the widened bridge is calculated. The proposed probabilistic framework is applied to a widened prestressed concrete T-girder bridge.

      PubDate: 2017-10-17T08:52:26Z
  • Ultimate strength of horizontally curved steel I-girders with equal end
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Keesei Lee, James S. Davidson, Junho Choi, Youngjong Kang
      Even under gravitational loading alone, horizontally curved girders experience not only bending moment but also torsional moment. The torsional moment acting on open sections simultaneously produces shear and normal stress due to pure and warping torsion respectively. Consequently, bending moment, pure torsion and warping torsion are coupled, which results in a very complicated stress state that makes it difficult to calculate the ultimate strength of horizontally curved members. This study revealed that the initial curvature can reduce the ultimate strength of horizontally curved members by up to 50%. Although current design specifications such as the AASHTO LRFD Bridge Design Specifications, suggest some alternatives, the exact behavior of a curved member cannot be considered well with those provisions. While it is true that the one-third rule is convenient to apply and gives good results, there is no strength equation for curved members. In order to derive an adequate strength equation for curved members, this research suggests a new concept of ultimate state. Finite element analysis using ABAQUS is used to consider the effects of sectional rigidities for bending, pure torsion and non-uniform torsion separately. Finally, an ultimate strength equation is suggested for simply supported curved girders that are subjected to equal end moments.

      PubDate: 2017-10-17T08:52:26Z
  • Fatigue tests of welded connections between longitudinal stringer and deck
           plate in railway bridge orthotropic steel decks
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Bin Cheng, Xinger Cao, Xinghan Ye, Yishan Cao
      This research presented the fatigue tests of longitudinal stringer-to-deck (SD) welded connections, which have been identified as the locations most sensitive to fatigue damage in the orthotropic steel decks (OSDs) of railway bridges. Four full-scale SD connections were fabricated, and two loading patches were considered. Static loading was first carried out to obtain the structural hot spot stresses at weld toes as well as stress concentration factors (SCFs), by which the hot spots providing the highest stresses were identified. Cyclic loading was then implemented next to the static loading, and the behaviors including fatigue crack initiation and propagation process, fatigue failure mode, characteristic fatigue life, as well as degradation of vertical rigidity, were all obtained from the test. The crack growing process can be totally divided into four stages, and the fatigue lives after the crack arrived at the deck edge were very short. Variations of crack dimensions were also obtained, and the simplified formulae of crack growth rate were numerically fitted so that the crack propagation lives can be predicted by using the crack dimensions. Comparisons also show that the FAT 100 curve in IIW fatigue design recommendation could overestimate the fatigue resistance of such connections where double-sided fillet welds were used to connect the stringer web and the deck plate, and therefore double-sided groove welds with partial or full penetrations are recommended for the stringer-to-deck connections in railway bridge decks.

      PubDate: 2017-10-17T08:52:26Z
  • The quasi-static cyclic behaviour of CFRP-to-concrete bonded joints: An
           experimental study and a damage plasticity model
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Hao Zhou, Dilum Fernando, Guangming Chen, Sritawat Kitipornchai
      In reinforced concrete structures strengthened using externally bonded fibre reinforced polymer (FRP) laminates, the performance of the bonded interface is vital to the performance of the strengthened structure. Extensive research has been carried out to study the behaviour of FRP-to-concrete bonded interfaces under quasi-static monotonic loading. However, only limited work has been done on understanding the behaviour of such bonded joints under quasi-static cyclic loading, which is a key issue to be addressed in modelling the long-term performance of carbon FRP (CFRP)-to-concrete bonded joints. This paper presents an experimental and theoretical study aimed at investigating and modelling the behaviour of CFRP-to-concrete bonded joints under quasi-static cyclic loading. A series of CFRP-to-concrete single lap shear pull-off tests were carried out under both quasi-static monotonic and cyclic loading. A thermodynamically consistent damage plasticity model where the damage parameter is defined as a function of the ratio between dissipated and total interfacial fracture energy was then proposed for modelling the constitutive behaviour of the CFRP-to-concrete bonded interface under quasi-static cyclic loading. The function to define the damage parameter was calibrated using the test results. Proposed model was then used to predict the bond-slip and load–displacement behaviour of the single lap shear pull-off tests. Results were compared with the experimental results and the prediction from two of the other existing models. Compared to the existing numerical models, the proposed model showed a better agreement with the test results.

      PubDate: 2017-10-17T08:52:26Z
  • Bridge damage detection using vehicle axle-force information
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Eugene J. OBrien, Paul C. Fitzgerald, Abdollah Malekjafarian, Enrique Sevillano
      Moving Force Identification (MFI) is the process of back-calculating the applied axle force histories from bridge measurements. This paper investigates the use of an MFI algorithm to detect the presence of bridge damage by monitoring calculated vehicle applied axle forces. Bridge deflections at three points along the bridge are used as the input to the algorithm. It is found that the combination of mean calculated gross vehicle weight and mean calculated axle weight ratio for a population of similar two-axle vehicles can be combined to indicate the location and severity of damage on a bridge. The bridge is modelled as a simply supported beam and deflections at the quarter point, midpoint and three quarter point are used as the inputs to the MFI algorithm. The method is shown to work best when damage is closer to the centre of the bridge.

      PubDate: 2017-10-17T08:52:26Z
  • Identification of moving vehicle parameters using bridge responses and
           estimated bridge pavement roughness
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Haoqi Wang, Tomonori Nagayama, Boyu Zhao, Di Su
      Passing vehicles cause bridge deformation and vibration. Overloaded vehicles can result in fatigue damage to, or even failure of, the bridge. The bridge response is related to the properties of the passing vehicles, particularly the vehicle weight. Therefore, a bridge weigh-in-motion system for estimating vehicle parameters is important for evaluating the bridge condition under repeated load. However, traditional weigh-in-motion methods, which involve the installation of strain gauges on bridge members and calibration with known weight truck, are often costly and time-consuming. In this paper, a method for the identification of moving vehicle parameters using bridge acceleration responses is investigated. A time-domain method based on the Bayesian theory application of a particle filter is adopted. The bridge pavement roughness is estimated in advance using vehicle responses from a sensor-equipped car with consideration of vehicle-bridge interaction, and it is utilized in the parameter estimation. The method does not require the calibration. Numerical simulations demonstrate that the vehicle parameters, including the vehicle weight, are estimated with high accuracy and robustness against observation noise and modeling error. Finally, this method is validated through field measurement. The resulting estimate of vehicle mass agrees with the measured value, demonstrating the practicality of the proposed method.

      PubDate: 2017-10-17T08:52:26Z
  • Predictive model for the seismic vulnerability assessment of small
           historic centres: Application to the inner Abruzzi Region in Italy
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Giuseppe Brando, Gianfranco De Matteis, Enrico Spacone
      The paper presents a predictive model for assessing the seismic vulnerability of small historic centres. The model, developed in the framing of other similar methods proposed in the past, needs a limited number of parameters and is based on information collected in the aftermath of the 2009 L’Aquila earthquake. First, a damage survey carried out on two historic centres hit by L’Aquila earthquake is presented and the most recurrent failure types are classified in terms of severity and extension, leading to damage probability matrices (DPMs). Second, the proposed predictive model is calibrated on the basis of simple observations on the buildings’ structural features. Finally, the model is validated through the application to a third historic centre characterized by the same features of the first two case studies. This application proves the generality of the proposed procedure by accurately reproducing the damage that was actually reported after the 2009 earthquake. The model provides useful information on the most effective anti-seismic strategies that could be implemented at the urban scale for seismic risk reduction.

      PubDate: 2017-10-17T08:52:26Z
  • Static and dynamic displacement measurements of structural elements using
           low cost RGB-D cameras
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Jean Michel Franco, Byron Mauricio Mayag, Johannio Marulanda, Peter Thomson
      Optical displacement measurements can provide data of the behavior of structural elements without altering key parameters such as damping, stiffness, or mass. Optical techniques can also reduce costs and substantially simplify the equipment required to acquire data effectively and map displacements at specific locations of elements with complex geometries, such as steel connections. In addition, these techniques can provide simultaneous data at multiple points using a single device, hence lowering instrumentation costs. For example, motion capture systems are used in applications that range from medicine to cinematography, and involve different types of imaging techniques. However, their application to civil and mechanical structures is complex and costly. On the other hand, range/depth cameras can provide a 3-D imaging solution to capture motion at an affordable cost. These cameras are widely available and used in the videogame industry. This paper presents the characterization and implementation of a methodology for the measurement of large-displacements using artificial vision techniques, for structural applications such as experimental modal analysis, cyclic loading tests, creep tests, and static displacements tests. Two low cost depth-cameras, one a time-of-flight camera and the other a structured light camera, were calibrated, evaluated and implemented in static and dynamic tests, during a full-scale reinforced concrete wall cyclic load test and shaking table tests. The results show that both devices provide high accuracy measurements in comparison with commonly used sensors for displacement measurements, with the added advantages of being contactless and providing three-dimensional information.

      PubDate: 2017-10-17T08:52:26Z
  • Calculation model to assess the structural behavior of LVL-concrete
           composite members with ductile notched connection
    • Abstract: Publication date: 15 December 2017
      Source:Engineering Structures, Volume 153
      Author(s): Lorenzo Boccadoro, Simon Zweidler, René Steiger, Andrea Frangi
      This paper presents an analytical model of timber-concrete composite slabs made of laminated veneer lumber (LVL) with notched connection. Timber-concrete composite slabs could be used as alternative to timber slabs or conventional reinforced concrete slabs and represent an interesting solution due to ecologic, economic and structural advantages. The use of LVL products guarantees for controllable and homogeneous properties of the timber part of the composite member and allows taking advantage of the high mechanical properties of hardwood (e.g. beech). The advantages of the notch as timber-concrete connection system are its high stiffness and the possibility to achieve a ductile compressive failure of timber. The presented analytical model is based on simple equilibrium formulations and allows the development of a ductile and reliable design procedure based on notch yielding. Because of the difference between the material properties of LVL and concrete, local LVL deformations within the notches may compromise the shear-carrying mechanism in concrete, leading to premature failure of the composite member. This problem can be solved by installing vertical reinforcement. The model has been validated by means of full scale bending tests on timber-concrete composite members made of beech LVL plates.

      PubDate: 2017-10-17T08:52:26Z
School of Mathematical and Computer Sciences
Heriot-Watt University
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