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  Subjects -> ENGINEERING (Total: 2449 journals)
    - CHEMICAL ENGINEERING (208 journals)
    - CIVIL ENGINEERING (208 journals)
    - ELECTRICAL ENGINEERING (116 journals)
    - ENGINEERING (1288 journals)
    - ENGINEERING MECHANICS AND MATERIALS (394 journals)
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    - INDUSTRIAL ENGINEERING (81 journals)
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CIVIL ENGINEERING (208 journals)                  1 2 | Last

Showing 1 - 200 of 208 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 20)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 3)
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 3)
Advances in Civil Engineering     Open Access   (Followers: 41)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 33)
Agregat     Open Access   (Followers: 1)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 35)
Architectural Engineering     Open Access   (Followers: 5)
Architecture and Engineering     Open Access  
Architecture, Civil Engineering, Environment     Open Access  
Archives of Civil and Mechanical Engineering     Full-text available via subscription   (Followers: 3)
Archives of Civil Engineering     Open Access   (Followers: 12)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 4)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 7)
Baltic Journal of Road and Bridge Engineering     Open Access   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 2)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 3)
Berkeley Planning Journal     Open Access   (Followers: 5)
Bioinspired Materials     Open Access   (Followers: 5)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 14)
Building & Management     Open Access   (Followers: 2)
Building and Environment     Hybrid Journal   (Followers: 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: 13)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 11)
Case Studies in Structural Engineering     Open Access   (Followers: 9)
Cement and Concrete Composites     Hybrid Journal   (Followers: 20)
Challenge Journal of Concrete Research Letters     Open Access   (Followers: 3)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 5)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 8)
Civil and Environmental Engineering Reports     Open Access   (Followers: 8)
Civil and Environmental Research     Open Access   (Followers: 17)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 23)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 3)
Civil Engineering and Technology     Open Access   (Followers: 12)
Civil Engineering Dimension     Open Access   (Followers: 11)
Civil Engineering Infrastructures Journal     Open Access   (Followers: 1)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 290)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 11)
Computers & Structures     Hybrid Journal   (Followers: 37)
Concrete Research Letters     Open Access   (Followers: 7)
Construction Economics and Building     Open Access   (Followers: 4)
Construction Engineering     Open Access   (Followers: 11)
Construction Management and Economics     Hybrid Journal   (Followers: 21)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 3)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 17)
Enfoque UTE     Open Access   (Followers: 4)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 7)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Open Access   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 10)
Environmental Geotechnics     Hybrid Journal   (Followers: 5)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 10)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 19)
Frontiers in Built Environment     Open Access   (Followers: 1)
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 6)
Geomaterials     Open Access   (Followers: 3)
Geosystem Engineering     Hybrid Journal   (Followers: 2)
Geotechnik     Hybrid Journal   (Followers: 4)
Géotechnique Letters     Hybrid Journal   (Followers: 8)
GISAP : Technical Sciences, Construction and Architecture     Open Access  
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indonesian Journal of Urban and Environmental Technology     Open Access  
Indoor and Built Environment     Hybrid Journal   (Followers: 3)
Infrastructure Asset Management     Hybrid Journal   (Followers: 3)
Infrastructures     Open Access  
Ingenio Magno     Open Access   (Followers: 1)
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 30)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 3)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 17)
International Journal of Civil, Mechanical and Energy Science     Open Access   (Followers: 2)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 15)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 2)
International Journal of Construction Engineering and Management     Open Access   (Followers: 10)
International Journal of Engineering and Geosciences     Open Access  
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Masonry Research and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Pavement Research and Technology     Open Access   (Followers: 6)
International Journal of Protective Structures     Hybrid Journal   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 9)
International Journal of Structural Integrity     Hybrid Journal   (Followers: 2)
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Built Environment     Open Access   (Followers: 5)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 8)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 7)
International Journal Sustainable Construction & Design     Open Access   (Followers: 2)
Journal of Applied Research in Water and Wastewater     Open Access   (Followers: 1)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 13)
Journal of Building Engineering     Hybrid Journal   (Followers: 2)
Journal of Building Materials and Structures     Open Access   (Followers: 2)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering     Open Access  
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 15)
Journal of Civil Engineering and Management     Open Access   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 9)
Journal of Civil Engineering Research     Open Access   (Followers: 7)
Journal of Civil Engineering, Science and Technology     Open Access   (Followers: 1)
Journal of Civil Society     Hybrid Journal   (Followers: 5)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 4)
Journal of Composites     Open Access   (Followers: 78)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 13)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 23)
Journal of Construction Engineering     Open Access   (Followers: 9)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 17)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 6)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 4)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 6)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 2)
Journal of Green Building     Full-text available via subscription   (Followers: 10)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 14)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 19)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 5)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials and Engineering Structures     Open Access   (Followers: 5)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 8)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 9)
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 3)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 6)
Journal of Rehabilitation in Civil Engineering     Open Access   (Followers: 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: 35)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Structural Mechanics     Open Access   (Followers: 1)
Journal of Structures     Open Access   (Followers: 4)
Journal of Sustainable Architecture and Civil Engineering     Open Access   (Followers: 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: 2)
Journal of Water and Environmental Nanotechnology     Open Access  
Journal of Water and Wastewater / Ab va Fazilab     Open Access  
Jurnal Spektran     Open Access   (Followers: 1)
Jurnal Teknik Sipil     Open Access  
Jurnal Teknik Sipil dan Perencanaan     Open Access   (Followers: 1)
Konstruksia     Open Access  
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 2)
Latin American Journal of Solids and Structures     Open Access   (Followers: 4)
Materiales de Construcción     Open Access   (Followers: 1)
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 4)
Media Komunikasi Teknik Sipil     Open Access  
Mokslas – Lietuvos ateitis / Science – Future of Lithuania     Open Access  
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 15)
npj Materials Degradation     Open Access  
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 9)
Periodica Polytechnica Civil Engineering     Open Access  
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 4)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 14)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 10)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 2)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 3)
Promet : Traffic &Transportation     Open Access  
Random Structures and Algorithms     Hybrid Journal   (Followers: 5)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 5)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 6)
Resilience     Open Access   (Followers: 1)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Revista Sul-Americana de Engenharia Estrutural     Open Access  
Road Materials and Pavement Design     Hybrid Journal   (Followers: 11)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 5)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 61)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 5)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 3)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 11)
Structural Concrete     Hybrid Journal   (Followers: 11)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 8)
Structural Engineering International     Full-text available via subscription   (Followers: 11)
Structural Mechanics of Engineering Constructions and Buildings     Open Access   (Followers: 1)
Structural Safety     Hybrid Journal   (Followers: 6)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 24)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 12)
Structures     Hybrid Journal   (Followers: 1)
Study of Civil Engineering and Architecture     Open Access   (Followers: 10)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access   (Followers: 1)
Teknik     Open Access  
Territorium : Revista Portuguesa de riscos, prevenção e segurança     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 6)

        1 2 | Last

Journal Cover
Engineering Structures
Journal Prestige (SJR): 1.69
Citation Impact (citeScore): 3
Number of Followers: 13  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0141-0296
Published by Elsevier Homepage  [3162 journals]
  • Comparison of in-plane and out-of-plane failure modes of masonry arch
           bridges using discontinuum analysis
    • Abstract: Publication date: 1 January 2019Source: Engineering Structures, Volume 178Author(s): Bora Pulatsu, Ece Erdogmus, Paulo B. Lourenço This research aims to provide a better understanding of the structural behavior of masonry arch bridges using advanced modeling strategies. Two main contributions are achieved in this article; first, triggering mechanisms for the out of plane failure of spandrel walls are established; second, the influence of soil backfill on the behavior and strength of the bridges is presented through a comprehensive parametric study. Here, masonry arch bridges are modeled using a discontinuum approach, composed of discrete blocks, including also a continuum mesh to replicate infill material, adopting a framework of discrete element modeling. The equations of motion for each block are solved by an explicit finite-difference method, using the commercial software 3DEC. The results of the preliminary analyses are compared with analytical solutions and limit state analysis for validation purposes. Different arch bridge models, representing common geometrical properties in the northwest Iberian Peninsula are analyzed. Transverse effects, damage patterns and collapse mechanisms are discussed under different types of loading. The analysis demonstrated the severe capacity reduction due to spandrel wall failures and the importance of soil backfill in results, only possible by taking advantage of the performed numerical modeling strategy.
       
  • Simulation of control characteristics of liquid column vibration absorber
           using a quasi-elliptic flow path estimation method
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): P. Chaiviriyawong, P. Panedpojaman, S. Limkatanyu, T. Pinkeaw Tuned liquid column dampers (TLCDs) and liquid column vibration absorbers (LCVAs) are good substitutes for mechanical dampers to counter seismic activity exerted to tall buildings. The existing simplified effective length method could predict good results corresponding to test outcomes on TLCDs and LCVAs with small transition zones, but is found to yield larger discrepancy as larger transition zones are needed, often due to limited space constraints. The numerical panel method could be effectively employed to give more accurate results, but is not simple to formulate and needs to be re-modified for each new configuration. This paper proposes a new quasi-elliptic flow path estimation method to simulate control characteristics of TLCDs and LCVAs with relatively large transition boundary between the vertical columns and the horizontal cross-over duct, since liquid velocity’s variation inside the large transition boundary cannot be assumed to occur at a single point. The simulation results are compared with experimental investigations conducted on a shake table, yielding satisfactorily better outcomes for large transition zones, as well as for small transition zones. This new formulation has been verified with a few other studies and has been found to be an excellent viable option with a respectable better, or at least comparable, accuracy level.
       
  • Higher order beam theory for linear local buckling analysis
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Amalia K. Argyridi, Evangelos J. Sapountzakis In this paper, a higher order beam theory is employed for linear local buckling analysis of beams of homogeneous cross-section, taking into account warping and distortional phenomena due to axial, shear, flexural, and torsional behavior. The beam is subjected to arbitrary concentrated or distributed loading, while its edges are restrained by the most general linear boundary conditions. The analysis consists of two stages. In the first stage, where the Boundary Element Method is employed, a cross-sectional analysis is performed based on the so-called sequential equilibrium scheme establishing the possible in-plane (distortion) and out-of-plane (warping) deformation patterns of the cross-section. In the second stage, where the Finite Element Method is employed, the extracted deformation patterns are included in the buckling analysis multiplied by respective independent parameters expressing their contribution to the beam deformation. The four rigid body displacements of the cross-section together with the aforementioned independent parameters constitute the degrees of freedom of the beam. The finite element equations are formulated with respect to the displacements and the independent warping and distortional parameters. The buckling load is calculated and is compared with beam and 3d solid finite elements analysis results in order to validate the method and demonstrate its efficiency and accuracy.
       
  • Development of hysteretic energy compatible endurance time excitations and
           its application
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Mohammadreza Mashayekhi, Homayoon E. Estekanchi, Hassan Vafai, S. Ali Mirfarhadi The aim of this study is to develop a new simulation procedure of endurance time excitations in which hysteretic energy compatibility is included. Existing methods for simulating excitations consider only amplitude and frequency content of motions and disregard parameters related to cumulative damage of structures. Hysteretic energy consistency, as a cumulative damage-related parameter, is included in the process. The proposed method is applied to generate new excitations. Efficiency of the proposed method is examined in two ways: (1) comparing damage spectra of simulated excitations with recorded ground motions; (2) applying simulated excitations in seismic assessment of three concrete special moment frame structures. Results show considerable compatibility of damage spectra with time history analysis as compared to previous excitations and, therefore, imply an improvement in the simulation process. In the second examination, engineering demand parameters in terms of maximum values and distribution of responses over structural height are predicted by the endurance time analysis and, then, are compared with incremental dynamic analysis results. These comparisons show that the endurance time method can successfully predict seismic demands of structures using the new generated excitations in comparison with existing ones. Finally, it is deduced from results that the proposed method can be employed as an alternative simulation approach for new applications.
       
  • Characterization of the effect of CFRP reinforcement on the fatigue
           strength of aluminium alloy plates with fastener holes
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Zhi-Yu Wang, Tao Zhang, Xiaolei Li, Qing-Yuan Wang, Wanqiu Huang, Mengqin Shen In this paper the characteristics of CFRP reinforcement on the improvement of the fatigue strength of aluminium alloy plates with fastener holes are investigated. The CFRP reinforcement schemes including the number of laminate layers, single-sided and double-sided strengthening are taken into account. Fatigue tests with constant loading amplitude were conducted to compare different failure mechanisms involved with such structural details. The stiffness degradation of test specimen failed by interfacial debonding is shown to be relatively gradual prior to plate rupture while the propagation of the fatigue crack at the transition of the punching surface appears to be retarded to some extent due to the tensile strengthening of the carbon fibre. The contributions of carbon fibre and adhesive interface to the strength improvement are quantified. Discussions are also made for the fatigue life of similar details with some other hole forming methods reported in the literature. Recommendations are given for the assessment of the fatigue life of CFRP reinforced specimens studied herein with appropriate detail classes codified in the BS8118 standard. Finally, a new formula allowing for the contributions of the plate and carbon fibre in tension, the adhesive interface in shear and additional secondary bending effect is proposed in the evaluation of the improvement fatigue endurance. The proposed formula is verified from a good correlation with finite element analytical results and from original test data with a notable reduction of scatters. Its application scope is also discussed.
       
  • Fully composite beams with U-shaped steel girders: Full-scale tests,
           computer simulations, and simplified analysis models
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Lanhui Guo, Yong Liu, Bing Qu This paper focuses on the fully composite beam consisting of the U-shaped steel girder and angle connectors. Through the four-point bending tests of six full-scale specimens, the authors experimentally evaluated the flexural behavior of the fully composite beams. The specimens were intentionally varied to have different shear transfer capacities along the interfaces between the concrete slabs and the U-shaped girders and different geometries of the U-shaped girders. Test results show that all the specimens were fully composite and exhibited the favorable ductile flexural behavior. Computer models were then developed for the experimental specimens. It was found that the computer models were able to replicate the nonlinear behavior of the experimental specimens observed during the tests. Based on the computer models, parametric analyses were performed to investigate the influences of the residual stresses in the U-shaped girder, the strengths of construction materials, the geometries of the U-shaped girder and concrete slab on the strength of the fully composite beam. Beyond the computer models, simplified analysis models that are based on the assumed strain and stress diagrams and can be implemented through hand calculations were developed to capture the nonlinear moment-curvature responses of the composite beams. It is found that the results from the simplified analysis models agree well with the computer models. The simplified analysis models are thus recommended for future practice.
       
  • Comparative seismic loss analysis of an existing non-ductile RC building
           based on element fragility functions proposals
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Fabio Romano, Marco Faggella, Rosario Gigliotti, Maria Zucconi, Barbara Ferracuti A comparative seismic loss analysis is presented for a non-ductile infilled reinforced concrete building evaluating the influence on direct economic losses of different parameters characterizing a building performance model. Propagation of uncertainties to seismic repair cost estimate is investigated in terms of effect of input intensity measures, definition of element fragility and consequence functions specific to non-ductile RC buildings through incremental dynamic analyses and probabilistic performance-based earthquake engineering methodologies. A set of element fragility and consequence functions has been proposed based on experimental data for internal and external beam column joints and on analytical models for masonry infill walls. A quantitative estimate of indirect losses is proposed based on past earthquakes data, incorporating the building inactivity and the delay in the beginning of the reconstruction process. Seismic loss assessment is presented at single hazard levels and critically compared, providing insight into different possible alternatives for performance models implementation. A fully probabilistic life-cycle analysis is carried out to present realistic risk analysis figures for non-ductile reinforced concrete buildings.
       
  • Fatigue evaluation of rib-to-deck welded joint using averaged strain
           energy density method
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Pengjun Luo, Qinghua Zhang, Yi Bao, Aixin Zhou This paper investigates the feasibility of an averaged strain energy density (SED) method for fatigue evaluation of rib-to-deck weld joint in orthotropic steel deck. The effect of weld geometry on fatigue resistance of rib-to-deck joint is evaluated. The analysis results of the presented average SED method are validated against fatigue testing data and compared with the results of the conventional hot-spot stress and effective notch stress methods. A W-N curve is derived using the averaged SED method and used for evaluating the fatigue strength of rib-to-deck welded joints. The averaged SED method is also used to investigate the effect of weld geometrical variables on the fatigue failure mode transition, and the fatigue strength of full-scale orthotropic steel deck specimens. The results indicate that the averaged SED method provides superior ability in evaluating fatigue resistance and failure mode of rib-to-deck welded joint.
       
  • Enhancement of a meso-scale material model for nonlinear elastic finite
           element computations of plain-woven fabric membrane structures
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Jan Gade, Roman Kemmler, Michael Drass, Jens Schneider Due to their structure of crossed yarns embedded in coating, woven fabric membranes are characterised by a highly nonlinear stress-strain behaviour. In order to determine an accurate structural response of membrane structures, a suitable description of the material behaviour is required. Typical phenomenological material models like linear-elastic orthotropic models only allow a limited determination of the real material behaviour. A more accurate approach becomes evident by focusing on the meso-scale, which reveals an inhomogeneous however periodic structure of woven fabrics. The present work focuses on an established meso-scale model. The novelty of this work is an enhancement of this model with regard to the coating stiffness. By performing an inverse process of parameter identification using a state-of-the-art Levenberg-Marquardt algorithm, a close fit w.r.t. measured data from a common biaxial test is shown and compared to results applying established models. Subsequently, the enhanced meso-scale model is processed into a multi-scale model and is implemented as a material law into a finite element program. Within finite element analyses of an exemplary full scale membrane structure by using the implemented material model as well as by using established material models, the results are compared and discussed.
       
  • Computational study of elastic and inelastic ring shaped – steel
           plate shear wall behavior
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Adam R. Phillips, Matthew R. Eatherton Ring shaped – steel plate shear walls (RS-SPSWs) are a new type of steel plate shear wall (SPSW) system that utilize strategic cutouts in a solid plate to mitigate shear buckling and encourage full hysteretic behavior and thus large energy dissipation. Previous experiments have demonstrated that the RS-SPSW concept can significantly reduce buckling and dissipate more energy than solid web plate SPSWs with similar strength. However, because of limitations in the number of tests and associated instrumentation, the experimental results did not provide enough data to thoroughly investigate several facets of RS-SPSW behavior, such as the distribution of shear deformation along the web plate height, web plate forces on the boundary elements, and web plate slenderness effects on buckling resistance.This paper details three computational studies that build upon the experimental test results to develop and validate useful design equations for RS-SPSWs. The paper starts with a description of the RS-SPSW nonlinear finite element models that utilize shell elements for the web plate. Then, the model is validated against experimental specimens by comparing the load-deformation behavior and the evolution of cumulative energy dissipation. Next, the computational models are utilized to explore the uneven shear deformation distribution along the height of the web plate allowing derived prediction equations to be validated. The computational models are also used to determine boundary element demands and to validate a proposed distribution of web plate forces for use in design. Lastly, the modeling approach is utilized to better understand shear buckling of the web plates in terms of non-dimensional web plate parameters.
       
  • Strength and deflection behaviour of cold-formed steel back-to-back
           channels
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Jun Ye, Seyed Mohammad Mojtabaei, Iman Hajirasouliha, Paul Shepherd, Kypros Pilakoutas Cold-formed steel (CFS) construction can lead to more efficient designs compared to hot-rolled steel members as a consequence of its high strength, light weight, ease of fabrication, and flexibility in their cross-section profiles. However, CFS members are vulnerable to local, distortional and overall buckling modes. This paper develops a numerical model to investigate the flexural strength and failure modes of CFS back-to-back channel beams and verifies the efficiency of an optimisation framework previously proposed. The model incorporates non-linear stress-strain behaviour and enhanced corner properties obtained from coupon tests, as well as initial geometric imperfections measured in physical specimens. To simulate the behaviour of a bolt bearing against a steel plate in the back-to-back section, a connector model is used that takes into account both slippage and bearing deformations. The developed Finite Element (FE) models are verified against six four-point bending tests on CFS back-to-back channel beams, where excellent agreement is found between the experimental results and the FE predictions. The validated FE models are then used to assess the adequacy of the effective width method in EC3 and the Direct Strength Method (DSM) in estimating the design capacity of conventional and optimum design CFS channel beam sections. The results indicate that both EC3 and DSM provide accurate predictions for the bending capacity of lipped channel beam sections. A comparison between FE predictions and tested results show that, the geometric imperfections can change the FE predictions of ultimate capacity by 7%, while the strain-hardening of CFS material at the round corners has negligible effects. It is also shown that EC3 uses a reduced cross-sectional property to calculate deflections, which can reasonably predict deflections with a slight overestimation (6%) at the serviceability load level.
       
  • A simplified non-linear structural analysis of reinforced concrete frames
           with masonry infill subjected to seismic loading
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Peter B.K. Mbewe, Gideon P.A.G. van Zijl Structural performance of both new and existing building structures under seismic actions can be assessed with a wide range of nonlinear static procedures and time history dynamic analysis available in literature. Most of these procedures, such as time history dynamic analysis, are complex as they require sophisticated finite element modelling. Reinforced concrete (RC) frames with masonry infill, for example, pose great challenge in modelling both the composite material behaviour and their interactions. With significant effort directed towards sustainable infrastructure development, a simplified nonlinear analytical procedure for evaluation of RC infill frames subjected to incremental horizontal loading is developed that can be used easily in integrated structural performance and sustainability evaluation. The method, developed on the premise of truss analogy and utilising the pushover analysis, assumes that all structural members of the RC frame are truss elements with homogeneous material properties derived on the basis of a pure axially loaded system and the infill masonry is converted into strut elements. Stiffness modification through evaluation of nonlinear stress-strain states is employed to generate the overall force-deformation behaviour of the structural system. Experimental data available in literature is used to validate the procedure.
       
  • Inelastic condensed dynamic models for estimating seismic demands for
           buildings
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): M.H. Tehrani, P.S. Harvey, H.P. Gavin, A.M. Mirza Computationally-efficient simulations of structural responses, such as displacements and inter-story drift ratios, are central to performance-based earthquake engineering. Calculating these responses involves potentially time-consuming response history analysis of inelastic structural behavior. To overcome this burden, this paper introduces a new inelastic model condensation (IMC) procedure. The method presented here is non-iterative and uses the modal properties of the full model (in the elastic range) to condense the structural model such that the condensed elastic model preserves the modal properties of the full model at certain modes specified by the analyst. Then, by replacing the inter-story elastic forces with hysteretic forces, the inelastic behavior of the full finite element model is incorporated into the condensed model. The parameters of these hysteretic forces are easily tuned, in order to fit the inelastic behavior of the condensed structure to that of the full model under a variety of simple loading scenarios. The fidelity of structural models condensed in this way is demonstrated via simulation for different ground motion intensities on three different building structures with various heights. The simplicity, accuracy, and efficiency of this approach could significantly alleviate the computational burden of performance-based earthquake engineering.
       
  • Impact of two columns missing on dynamic response of RC flat slab
           structures
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Kai Qian, Yun-Hao Weng, Bing Li Sudden removal of columns caused by unexpected extreme loading may increase the bending moment and shear force at surrounding column-slab connections significantly, which may trigger punching shear failure at these connections and lead to progressive collapse of entire reinforced concrete (RC) flat slab structures. To quantify the dynamic load redistribution of flat slab structures subjected to different extents of initial local damage (one-column or two-column removal), two multi-panel RC flat slab substructures were tested subjected to simulated sudden column removal scenarios. These two specimens have identical dimensions and reinforcement details. One of the substructures suffered a loss of an interior column scenario while another one was subjected to a two columns (one interior column and one edge column) missing scenario. The dynamic response, deformation shape, failure mode, and local strain gauge results are presented. It is found that although both specimens had exceeded their yield load capacity, no collapse occurred as considerable compressive membrane action developed in the RC slab to help redistribute the loads. With the drop panels, no punching shear failure was observed in the slab-column connections after removal of the column. To further study the progressive collapse robustness of flat slab structures, finite element (FE) models were validated and parametric studies were carried out. Numerical analysis indicated that the axial force initial carried by the lost columns may amplify up by 1.25 times before redistribution into surrounding columns. Moreover, the dynamic ultimate load capacity of Specimens S1 and S2 are as large as 1.92 and 1.18 times of their design service load, respectively.
       
  • Peak and residual responses of steel moment-resisting and braced frames
           under pulse-like near-fault earthquakes
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Cheng Fang, Qiuming Zhong, Wei Wang, Shuling Hu, Canxing Qiu This paper presents the behaviour of steel moment resisting and braced frames under pulse-like near-fault earthquakes. The key properties for characterizing near-fault ground motions with forward directivity and fling step effects are discussed, and the influence of varying brace properties on the key engineering demand parameters such as maximum inter-storey drift (MID), residual inter-storey drift (RID) and peak absolute floor acceleration (PA) is revealed. Among other findings, it is shown that the structural responses are related to spectral accelerations, PGV/PGA ratios, and the pulse period of near-fault ground motions. The moment resisting and self-centring braced frames (MRFs and SC-BRBFs) generally have comparable MID levels, while the buckling-restrained braced frames (BRBFs) tend to exhibit lower MIDs. Increasing the post-yield stiffness of the braces decreases the MID response. The SC-BRBFs generally have mean residual drifts less than 0.2% under all the considered ground motions. However, much larger RIDs are induced for the MRFs/BRBFs under the near-fault ground motions, suggesting that these structures may not be economically repairable after the earthquakes. From a non-structural performance point of view, the SC-BRBFs show much higher PA levels compared with the other structures. A good balance among the MID, RID, and PA responses can be achieved when “partial” SC-BRBs are used. To facilitate performance-based design, RID prediction models are finally proposed which enable an effective evaluation of the relationship between MID and RID.
       
  • Seismic behavior of recycled plastic lumber walls: An experimental and
           analytical research
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Juan P. Herrera, Daniel Bedoya-Ruiz, Jorge E. Hurtado Recycled Plastic Lumber (RPL) is a wood-like material made from recycled plastics that aims to diminish the environmental pollution resulting from plastic wastes. This material is used in different kinds of nonstructural and structural applications. Recently, RPL has been proposed as a suitable material to develop structural walls that comprise the seismic resistant system of housings, in order to lessen the housing deficiency. This article presents the results drawn from an experimental campaign carried out over three full-scale RPL walls, which were tested under cycling loading conditions to determine structural parameters such as strength, hysteretic behavior, ductility, energy dissipation, equivalent damping and characteristic failure modes of the RPL walls, which are necessary to design and to assess seismically the housings. Finally, a multilinear hysteretic model capable of simulating the nonlinear dynamic behavior exhibited by RPL walls was implemented, in order to simulate and to assess the seismic behavior of them under strong and destructive real earthquakes.
       
  • Design and testing of an adhesively bonded CFRP strengthening system for
           steel structures
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): S. Chataigner, K. Benzarti, G. Foret, J.F. Caron, G. Gemignani, M. Brugiolo, I. Calderon, I. Piñero, V. Birtel, F. Lehmann In the framework of sustainable development policies, it is essential that infrastructure owners can rely on effective repair or strengthening solutions, designed and tested in relevance to actual service conditions. In the case of steel structures, fatigue damage is a major concern that can significantly affect the lifespan of the structure, and so far, there are very few operational methods capable of preventing fatigue cracks in the field. Adhesively bonded carbon fiber reinforced polymer (CFRP) composites are being successfully applied to the rehabilitation of concrete structures for more than two decades, and they are currently receiving much interest for the strengthening of steel elements, but mainly for curative purpose after severe damage has occurred.In the present study, which is part of a European project called FASSTbridge, a specific CFRP system has been developed as a preventive method against fatigue damage of steel structures. The proposed system consists of a commercially available ultra-high modulus (UHM) CFRP composite plate compatible with the stiffness of the host steel structures, which is bonded to the steel support using a novel hybrid epoxy/polyurethane adhesive. A first part of the paper presents the main specifications that should be adopted in the design of CFRP strengthening systems applied to steel structures, and that were identified from an extensive literature survey. These specifications have guided the development of the polymer adhesive and the choice of a peculiar commercial CFRP plate in the preliminary phase of the project. Experimental characterizations were then conducted (i) on the formulated hybrid polymer adhesive to optimize its curing schedule and check the previous specifications are fulfilled, and (ii) on CFRP reinforced steel specimens in order to verify the effectiveness of the proposed strengthening system. This experimental program involved both short term and durability tests that were performed by different laboratories. Such an inter-laboratory study made it possible to verify the performances of the developed strengthening system and to assess the influence of installation parameters and environmental conditions.
       
  • Seismic behavior of precast segmental UHPC bridge columns with replaceable
           external cover plates and internal dissipaters
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Zhen Wang, Jing-Quan Wang, Yu-Chuan Tang, Tong-Xu Liu, Yu-Feng Gao, Jian Zhang A new earthquake resilient ultra-high-performance concrete (UHPC) bridge column was proposed and fabricated with precast segmental construction. The bottom segment was divided into two parts: core zone and four replaceable surrounding UHPC plates, between which replaceable dissipaters were employed. Rapid repair was completed with substitutions of damaged replaceable components, including UHPC plates and dissipaters, after an earthquake. Cyclic loading tests were conducted on three 1:3 scaled specimens and their corresponding repaired specimens. The research parameters included post-tensioning (PT) force level and usage of replaceable dissipaters. The test results showed that both the construction and repair times could be decreased owing to the use of proposed bridge column. The damage to replaceable dissipaters and cover plates was significant, but the damage to core concrete was minimal. The original repaired specimens presented displacement capacities of at least 5% and 4% drift, respectively. All specimens showed excellent self-centering and had less than 0.8% residual drift until failure. Two different failure modes were found: cover plate failure in lateral bending failure, which significantly reduced the lateral load, and dissipater coupler failure, which caused dissipaters to work inefficiently and decreased energy dissipation. Compared with the original specimens, which failed in the same failure mode, the repaired specimen had similar lateral load and displacement capacities, but a lower initial stiffness. All PT tendons were elastic and no yield or rupturing was found, but the stress loss was significant. The rotation of the bottom joint dominated the lateral deformation, and the contribution of joint sliding can be neglected.
       
  • Structural performance of multi-story mass-timber buildings under
           tornado-like wind field
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Matiyas A. Bezabeh, Anant Gairola, Girma T. Bitsuamlak, Marjan Popovski, Solomon Tesfamariam Tall mass-timber buildings utilize engineered wood panels to form their main gravity and lateral load resisting systems, which makes them lighter and more flexible than buildings made from concrete, masonry or even steel. In general, drift sensitive components of tall mass-timber buildings could be susceptible to damages due to increased deflection when subjected to extreme wind storms like violent tornadoes. This paper assessed the structural performance of a multi-story mass-timber building, which was designed using the customary 1-in-50 years design wind speed of the 2010 National Building Code of Canada with a load factor of 1.4, under experimentally simulated tornado-like wind fields. In the study, wind loads were obtained from laboratory simulations of tornado-like wind field and atmospheric boundary layer flow at Western University, Canada. Tornadic wind loads from the laboratory tests were scaled to five Enhanced Fujita wind speeds, representing various levels of damage. Dynamic structural analyses were carried out in time-domain to include the possible amplification due to the dynamic component of the excitation and assess floor level inter-story drift and shear force demands for various parameters. The varied parameters were tornado intensity level, the orientation of the building (aerodynamic direction), and critical damping ratio. Based on the obtained results, the vulnerability of drift sensitive components of the study building under tornado-like wind field was estimated. It is shown that strong tornadoes may pose significant damage to drift sensitive non-structural components of multi-story mass-timber buildings. Finally, roadmaps to improve the design of mass-timber buildings in tornado-prone areas are forwarded.
       
  • Brittle failure in RC masonry infilled frames: The role of infill
           overstrength
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Gianni Blasi, Flavia De Luca, Maria Antonietta Aiello The interaction between an infill panel and a reinforced concrete (RC) column can lead to the brittle failure of the structural element. A novel combination of cutting-edge analytical modelling approaches for masonry infills and RC elements is employed to simulate five experimental tests (three infilled and two bare) characterized by brittle failure modes. The infill is modelled with a multi-strut idealisation, and the RC column is modelled using the recently developed PinchingLimitStateMaterial in OpenSees. The effects of the infill type (solid or hollow) and ductility characteristics of the RC elements on the optimal modelling parameters are investigated. The focus of this study is on the assumption of the overstrength ratio between the maximum and cracking strengths of the panel when brittle failure occurs. The preliminary assumption for this parameter is the widely accepted value of 1.3 suggested in the formulation by Panagiotakos and Fardis. This value is found to influence the shear failure simulation. To more accurately predict brittle failure, higher overstrength values of the infill are used in the numerical model to improve the matching between the numerical and experimental tests. These values are then compared with the approximate estimation of the overstrength ratio from a database of 98 experimental tests. The suggested estimation of the overstrength ratio is systematically greater than 1.3 and dependent on the infill type (i.e., 1.44 for hollow and 1.55 for solid infills). The proposed values can have a high impact on future code-compliant recommendations aimed at verifying the likelihood of the occurrence of brittle failure in columns due to their interaction with infill panels.
       
  • Modeling methods for gas quenching, low-pressure carburizing and
           low-pressure nitriding
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Emilia Wołowiec-Korecka Modern thermal and thermochemical treatment of steels is a rapidly growing research area. Thermochemical processes are researched, designed, optimized, and controlled by computer-aided methods. The goal of the present paper is to provide a comprehensive state-of-the-art review and to analyze the critical mass of knowledge in the field of modeling methods to describe the interactions between the processing, microstructure and postoperative properties of the treated material. This article briefly discusses modern low-pressure thermochemical processes to describe the difficulties in modeling their non-equilibrium nature and transient states that occur in the course of the processes. A synthetic review of modeling methods, in particular, artificial intelligence methods, is presented to investigate low-pressure thermochemical processes. The opportunities and dangers associated with these methods are also analyzed.
       
  • Structural performance of cold-formed high strength steel tubular columns
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Han Fang, Tak-Ming Chan, Ben Young This paper presents a numerical investigation into the structural performance of cold-formed high strength steel tubular columns with square, rectangular and circular cross-sections. A finite element model was developed and validated against experimental results on the cold-formed high strength steel tubular columns. Parametric studies using the validated finite element model were carried out to determine the strengths of cold-formed tubular columns with various cross-sectional dimensions, member slenderness values, geometric imperfections and steel grades of S700, S900 and S1100. It was found that increasing the steel grade of the columns led to higher normalised column strengths which were less severely affected by geometric imperfections. The effect of material tensile strength to yield strength ratio on the column strengths was found to be insignificant. Based on the experimental results in literature and the results obtained from parametric studies, the applicability of the design rules in European, Australian and American Standards to cold-formed high strength steel tubular columns was evaluated. The reliability of the design rules was also assessed by performing reliability analysis. The design rules in these standards provide conservative predictions for the strengths of cold-formed high strength steel tubular columns. Recommendations on the column buckling curve selection are discussed. An improved column buckling curve expression considering the increment in normalised column strength with increasing steel grade is also proposed.
       
  • Pull-through capacities of cold-formed steel roof battens considering
           loading rate sensitivity
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Kathekeyan Myuran, Mahen Mahendran, Mayooran Sivapathasundaram Static and fatigue pull-through failures of thin steel roof battens in the vicinity of batten to rafter screw connections are part of the major premature connection failures which lead to severe roof failures during high wind events. As wind speed and thereby wind uplift loading rate on a building roof varies over a wide range, the loading rate which should be used to conduct prototype roof tests is a moot point. Current wind loading standards and guidelines recommend a wider range of loading rates/frequencies in simulating static and cyclic wind loads. This could adversely affect the test results of loading/strain rate sensitive materials. Since cold-formed steels appear to be sensitive to loading rate, it is necessary to investigate the effect of loading rate on both static and fatigue pull-through capacities of cold-formed steel roof battens. Therefore, a series of static and cyclic pull-through tests was conducted at various loading rates on roof battens made of two grades (G300 and G550) and two thicknesses (0.75/0.80 and 0.95/1.00 mm). Test results showed that both static and fatigue pull-through capacities increase with increasing loading rate. To understand the loading rate sensitivity of roof battens, the effect of loading rate on the ultimate tensile strength of cold-formed steels was also investigated through a series of tensile coupon tests. Based on both pull-through and tensile coupon test results, suitable modifications and recommendations have been made to the current pull-through capacity equations and the current Low-High-Low (LHL) cyclic test loading frequency. A suitable material model is also proposed to determine the dynamic mechanical properties of cold-formed steels.
       
  • Thermal effect on vibration and buckling analysis of thin
           isotropic/orthotropic rectangular plates with crack defects
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): S.K. Lai, L.H. Zhang The present research is concerned with the vibration analysis of thin isotropic and orthotropic rectangular plates with crack defects under thermal environmental conditions. In the literature, there are only few studies reported in this direction. Based on the classical plate theory, the governing equations of the isotropic and orthotropic cracked rectangular plates can be derived, in which a surface crack located at the plate center is formulated based on a line-spring model. Since the dynamic behavior of structural elements is significantly affected by thermal effects, a thermal buckling analysis for isotropic and orthotropic plates is also conducted. A uniform heating load on the cracked rectangular plates is considered and the critical buckling temperature of the plates with or without cracks is investigated. The discrete singular convolution (DSC) method is then applied to formulate the eigenvalue equations for the cracked rectangular plates under various thermal conditions. The DSC technique is an ingenious method in stability and dynamic analysis of plates, not only it is a flexible local method to handle complex geometries and boundary conditions, but also it performs as a global approach with a high degree of accuracy. To go beyond the limitation of the DSC method, the use of Taylor’s series expansion method is incorporated for the treatment of free boundary conditions. In addition, this is the first attempt to explore its application on the analysis of cracked rectangular plates under thermal effects. In this work, the vibration of isotropic and orthotropic cracked rectangular plates with various combinations of boundary conditions is studied. A special restrained manner of simply supported conditions that are permissible for in-plane movements is also analyzed. The obtained solutions herein are compared with the existing results to verify the accuracy and reliability. Besides, accurate first-known solutions are also presented.
       
  • Design-level estimation of seismic displacements for self-centering SDOF
           systems on stiff soil
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Changxuan Zhang, Taylor C. Steele, Lydell D.A. Wiebe Self-centering systems, which are intended to survive a major earthquake with essentially no residual displacements, are drawing increasing attention from designers. Both force-based and displacement-based design methodologies require an estimate of the peak seismic displacements. Therefore, this study focuses on estimating the peak displacements of self-centering systems based on constant-strength (CR) displacement demand spectra, which are calculated from more than five million nonlinear time history analyses of single-degree-of-freedom (SDOF) systems using ground motions representing a site with stiff soil conditions. Because of the ability of self-centering systems to achieve large displacement capacities while also being relatively stiff in the linear range, this study includes much lower linear limits than are used to design traditional yielding systems. Self-centering systems are shown to have displacements that are generally larger than for corresponding elastic systems, and although supplemental energy dissipation decreases the peak displacements, the influence of increasing the energy dissipation ratio, β, decreases as β approaches 100%. The secondary stiffness has relatively little influence if it is positive and small, but a negative secondary stiffness can lead to unbounded response. Using a tangent stiffness proportional damping model instead of an initial stiffness proportional damping model increases the peak displacements and makes the results more sensitive to the energy dissipation and secondary stiffness. Regression analysis is used to develop a simple equation that can be used during design to estimate the displacement demands on self-centering systems. This equation is shown to achieve a reasonable balance between simplicity and accuracy for the design of four controlled rocking steel braced frames with heights between three and nine storeys.
       
  • Damage assessment in structures using combination of a modified Cornwell
           indicator and genetic algorithm
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): S. Tiachacht, A. Bouazzouni, S. Khatir, M. Abdel Wahab, A. Behtani, R. Capozucca This paper presents a new methodology for damage identification and quantification in two- and three-dimensional structures. The application of the proposed methodology is investigated numerically using Finite Element Method (FEM) and Matlab program. We propose a Modified Cornwell Indicator (MCI) that performs more efficient in damage detection than the standard Cornwell Indicator (CI). Furthermore, MCI is combined with Genetic Algorithm (GA) for further quantification of the detected damage. In GA, MCI, is used as an objective function to compare between measured and calculated indicators. The results of the analysis show that the proposed technique is accurate and efficient, when compared with other techniques in the literature, to estimate the severity of structural damage.
       
  • Computational modelling of the transformation of bistable scissor
           structures with geometrical imperfections
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): L.I.W. Arnouts, T.J. Massart, N. De Temmerman, P.Z. Berke In many applications structures need to be easily moveable, or assembled at high speed on unprepared sites. For this purpose, preassembled deployable structures, which consist of beam elements connected by hinges, are highly effective. Intended geometric incompatibilities between the members are introduced for instantaneous structural stability after deployment. In such bistable scissor structures, these incompatibilities result in the bending of some specific members that are under compression with a controlled snap-through behaviour. The main goal of this contribution is to qualitatively and quantitatively discuss the behaviour of bistable scissor structures during deployment. To do this, a 3D nonlinear structural model is proposed to simulate the deployment, including explicitly geometrical imperfections in a stochastic approach. The originality of this contribution is (i) the implementation of gravity, (ii) the geometrical imperfections and (iii) the extension of the numerical model to complex deployable structures. Bounds on geometrical tolerances on several uncertain parameters (length of the beams, eccentricity of the pivot points, hinge misalignment and finite hinge stiffness) are proposed based on non-linear finite element simulations on a single module transformation. The computational tool is then applied to structures consisting of multiple modules and the influence of geometrical imperfections is characterized.
       
  • Dynamic analysis of single-degree-of-freedom systems (DYANAS): A graphical
           user interface for OpenSees
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Georgios Baltzopoulos, Roberto Baraschino, Iunio Iervolino, Dimitrios Vamvatsikos Non-linear dynamic response of SDOF systems enjoys widespread application in earthquake engineering, sometimes as a testing ground for cumbersome analytical procedures, but often as a direct proxy of first-mode-dominated structures, within the family of simplified, pushover-based methods for seismic structural assessment and/or design. This article presents DYANAS, a MATHWORKS-MATLAB®-based graphical user interface that uses the OpenSees finite element platform to perform nonlinear dynamic analysis of single-degree-of-freedom (SDOF) oscillators. The scope of this open-source, freely distributed software is to serve as a tool for earthquake engineering research. The main advantages offered by the DYANAS interface are ease in the definition of the required analysis parameters and corresponding seismic input, efficient execution of the analyses themselves and availability of a suite of convenient, in-built post-processing tools for the management and organization of the structural responses. The types of dynamic analysis frameworks supported are incremental, multiple-stripe and cloud. Simultaneous consideration of pairs of uncoupled dynamic systems gives the possibility for intensity measures to refer to bidirectional ground motion. In the paper, an outline of the types of dynamic analysis frameworks typically used in performance-based earthquake engineering is provided, followed by a detailed description of the software and its capabilities, that include an array of post-processing tools. In order to properly place this software tool within its natural performance-based earthquake engineering habitat, some example applications are provided at the end of the paper.
       
  • Experiments on H-shaped high-strength steel beams with perforated web
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Ran Feng, Hongyong Zhan, Shangwei Meng, Jihua Zhu The study conducts an experiment on flexural behavior of H-shaped high-strength steel beams with perforated web subjected to both gradient and constant bending. A total of 12 specimens including narrow flange and wide flange H-section beams were tested, which were made of high-strength steel Q550D and TQ700MCD, respectively. The effects of the ratio of web depth to flange width (h/b), the ratio of flange width to thickness (b/tf), the ratio of web depth to thickness (h/tw), the ratio of hole diameter to web depth (d/h) and the number of holes in the web on the flexural behavior of H-shaped steel members with high strength were investigated. Test results consist of the failure mode, bending moment-midspan deflection curves as well as the strain distributions at the midspan and the perforated sections of H-shaped high-strength steel beams. It was found that the ultimate flexural strengths and the corresponding curvatures of the specimens under gradient bending are all greater than those of the specimens under constant bending. The flexural strengths of H-shaped high-strength steel members with or without holes in the web gained in the experiments were made the comparison with those determined from current designing guidelines of perforated or imperforated steel members. The comparison reveals that American National Standard (AISC 360-16) and North American Specification (NAS) are quite conservative; Eurocode 3 (EC3) is somewhat unconservative; Australian Standard (AS) and Chinese Coding (CC) are somewhat conservative. Furthermore, Direct Strength Method (DSM) is quite conservative, Steel Design Guide Series 2 and Continuous Strength Method (CSM) are somewhat conservative for the flexural behavior of H-shaped high-strength steel beams with perforated web.
       
  • Mitigation of heave response of semi-submersible platform (SSP) using
           tuned heave plate inerter (THPI)
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Ruisheng Ma, Kaiming Bi, Hong Hao The undesirable motions resulting from wave loading can lead to the long-term fatigue damage or even catastrophic sinking of offshore semi-submersible platforms (SSP). It is therefore by all means necessary to suppress the excessive vibrations of SSP. Many methods have been proposed to mitigate the heave motion of offshore platforms, such as using a fixed heave plate (FHP) to increase the draft and damping of the system, or adopting a tuned heave plate (THP) to form a tuned mass damper (TMD) system. In this paper, a novel inerter-based control system, namely a tuned heave plate inerter (THPI), is proposed for control of SSP heave vibrations. In this system, an inerter device, which can transform the linear motion into the high-speed rotational motion and thus significantly amplifies the physical mass of the system, is added to the THP to further improve the performance of conventional THP. Analytical studies are performed to investigate the effectiveness of the proposed method. The mean square heave motions of SSP without control device and with FHP, THP and THPI are stochastically formulated, and the optimal design parameters for THP and THPI are derived. Parametric studies are conducted to investigate the influences of the size and original depth of heave plate on the optimal performances of FHP, THP and THPI. Finally, a novel waterwheel inerter is developed to realize the suggested device. The analytical results show that THPI is more effective to mitigate the heave motion of SSP compared to the conventional methods, and the novel waterwheel inerter is capable of generating a large apparent mass by using a small waterwheel.
       
  • Towards an analytical formulation for fluid structure tank vibration
           analysis: Modal equivalency using granular materials
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Sinh-Khoa Nguyen, Pierre-Louis Chiambaretto, Miguel Charlotte, Philippe Villedieu, Joseph Morlier, Yves Gourinat This paper focuses on a new methodology for substitution of Liquid Hydrogen (LH2) contained in cryogenic tank in vibration analysis by using surrogate granular materials. Our analysis is limited to a 3D tank that is supposed to be fully filled with granular grains and tries to establish a modal equivalence between (tank fully filled with LH2) and (tank fully filled with granular grains) systems. For this, we determine required pre-stresses based on a homogenization technique from properties of grains. After reviewing some important mathematical formulations of vibration and homogenization model, an example of modal equivalence between these two systems is presented. Analytical results are also compared with numerical simulations in order to prove the suitability of the new method.
       
  • Step-by-step unbalanced force iteration method for cable-strut structure
           with irregular shape
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Qing Ma, Makoto Ohsaki, Zhihua Chen, Xiangyu Yan In the design process of a cable-strut structure, the desired shape is first defined and the prestress can be obtained if the geometry is feasible; otherwise, the geometry must be modified. Thus, the initial step for prestress calculation is to estimate the feasibility of the geometry. In this paper, a method called Unbalanced Force Iteration (UFI) is proposed to remove the unbalanced forces using the equilibrium and stiffness equations. Feasibility of the geometry can be judged by the convergence property of UFI. Self-stress modes can be directly obtained easily through UFI method, if initial geometry is feasible. For structures with infeasible initial geometry, the Step-by-Step UFI, which combines finite element analysis and UFI, is proposed to gradually move the nodes to feasible locations. Three examples of cable domes with feasible geometry and three examples of cable domes with irregular and infeasible initial geometry are presented to verify the ability of UFI and Step-by-Step UFI for designing new irregular and asymmetric cable-strut structures.
       
  • Cross-sectional behavior of cold-formed steel semi-oval hollow sections
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Man-Tai Chen, Ben Young This paper presents an investigation on the material properties, residual stress distributions and cross-sectional behavior of cold-formed steel semi-oval hollow sections. Four cross-section series were included in the test program. The test specimens were cold-formed from hot-extruded seamless steel circular sections. Tensile coupon tests were conducted on coupon specimens extracted from three critical locations, namely the flat, curved and corner portions, of each cross-section as well as half of the cross-section of a representative section. Membrane and bending residual stresses distributions on the representative section were measured in both longitudinal and transverse directions. In addition, initial geometric imperfections were measured for each cross-section series and stub column tests were conducted to determine the average stress–strain relationship over the complete cross-section in the cold-worked state and to examine the cross-sectional behavior of cold-formed steel semi-oval hollow sections. Furthermore, a finite element model was developed and validated against the test results. With the verified finite element model, an extensive parametric study over a wide range of cross-section geometries was performed. The load-carrying capacities of stub columns obtained from experimental and numerical investigation were compared with the design strengths predicted by the Direct Strength Method using the design equations originally developed for open sections and the Continuous Strength Method with the design curves originally developed for traditional tubular sections. The comparison results show that the existing design methods provide conservative design strength predictions. In this study, modification on the Continuous Strength Method is proposed, which is shown to improve the accuracy of the design strength predictions in a reliable manner.
       
  • Experimental and theoretical study of a lead extrusion and friction
           composite damper
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Xueyuan Yan, Zaixian Chen, Ai Qi, Xuan Wang, Shen Shi A new lead extrusion and friction composite damper (LEFCD) is proposed for multi-level seismic protection. Compared with conventional metallic dampers, LEFCD is an assembly of components which are changeable and can provide specific performances. For small and moderate earthquakes, the LEFCD uses only the lead extrusion dampers. For strong earthquakes, the LEFCD uses both the lead extrusion and friction dampers simultaneously to dissipate the seismic energy. To investigate the performance of LEFCD, theoretical analyses and experimental cyclic loading tests of LEFCD were carried out. Also, finite element models of the LEFCD were established and were compared with the testing results. The theoretical analysis results indicated that the LEFCD can provide different mechanical behaviors for different LEFCD setups. Results of testing and numerical analysis showed that the LEFCD had good energy dissipation capacity and that the finite element modeling was accurate compared to the test results.Graphical abstractGraphical abstract for this article
       
  • Vibration-based cable condition assessment: A novel application of neural
           networks
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Seyed Ehsan Haji Agha Mohammad Zarbaf, Mehdi Norouzi, Randall Allemang, Victor Hunt, Arthur Helmicki, Chandrasekar Venkatesh Vibration-based cable tension estimation methods demand complex computations especially when usage of comprehensive cable models is required. Avoiding mathematical calculations, this paper proposes a simple novel framework to estimate the cable tension based on Artificial Neural Networks (ANNs). Employing a comprehensive cable model, a set of data including cable length, cable mass per unit length, cable axial stiffness, cable bending stiffness, cable tension and the corresponding cable natural frequencies is generated for training, validation, and testing of the ANNs. The acquired ANNs are then used to estimate the cable tensions in new Ironton-Russell Bridge and the results are compared against the cable tensions directly measured by lift-off test. It will be shown that for new Ironton-Russell Bridge, using cable length, cable mass per unit length, cable axial stiffness, and first two cable natural frequencies as input features to ANNs, the cable tensions can be accurately estimated.
       
  • Experimental assessment of a novel steel tube connector in cross-laminated
           timber
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): J. Schneider, T. Tannert, S. Tesfamariam, S.F. Stiemer This paper summarises experimental investigations conducted on a novel connector assembly consisting of hollow steel tubes placed inside cross-laminated timber panels. The criteria that drove the connector development were: (i) easy to manufacture and install; (ii) high capacity, stiffness, and ductility; and (iii) neglectable damage to the timber. A total of 24 test assemblies with varying steel tube diameters (ranging from two to four inch) were tested using quasi-static monotonic and reversed cyclic loading. The results demonstrated that – when using an appropriate connection layout – the desired ductile steel yielding failure mechanism was initiated and wood crushing of any form was avoided. The tested configurations reached load-carrying capacities up to 58 kN, exhibited high stiffness (>15 kN/mm), and were classified as moderately to highly ductile. The research presented herein demonstrated that this novel connection assembly for cross-laminated timber panels can be utilized in seismic regions.
       
  • Effect of bond layer thickness on behaviour of steel-concrete composite
           connections
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Pankaj Kumar, Amar Patnaik, Sandeep Chaudhary The performance of steel–concrete composite structural members depends on the connection at the steel–concrete interface. Structural adhesives are gaining rapid recognition as the bonding material between steel and concrete interfaces. The thickness of adhesive layer in a composite connection plays a key role in maximising the bond capacity. In this paper, the effect of the change in thickness of adhesive layer on the capacity of connection, ultimate slip at the interface, and the shear stiffness of connection have been studied. Twenty-five test specimens were cast and tested under direct shear to achieve the optimum thickness of adhesive layer. The ultimate strength and relative slip of all five adhesive layer thicknesses of steel–concrete specimens, obtained through experimental studies, were verified using finite element analysis. The failure patterns of bonded connection were also critically observed and found to be varying with adhesive layer thickness. It changes from adhesive failure to mixed (adhesive and cohesive) failure, and from mixed failure to cohesive mode of failure, with increasing thickness. At the optimum thickness, the composite interface experiences a mixed mode of failure. The effectiveness of bonded connections over mechanical shear stud connections was outlined through a comparison of the load-slip behaviour of both.
       
  • Near- and far-field earthquake damage study of the Konitsa stone arch
           bridge
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Nikolaos Simos, George C. Manos, Evaggelos Kozikopoulos This paper reports on the sensitivity of earthquake response and damage of long span masonry stone bridges to near field (impulsive type) and far field earthquakes. Towards that objective, the Konitsa Bridge is used as a case study. The particular bridge was selected for offering certain unique features such as long span, built right on an active fault, survived a recent pair of near-filed type earthquakes with minimal damage and finally, construction material mechanical properties and strength could be deduced from a recently collapsed similar bridge in the area. The multifaceted study integrated in-situ measurements of dynamic characteristics, laboratory tests on representative stone and mortar materials and a series of finite-element analyses based on non-linear modelling using a combination of discontinuous and continuous representations to capture the behavior of bridge structural component interface and interaction as well as mortar-stone interaction and failure. In addition to the ground motion records of the recent seismic activity at the Konitsa Bridge location, four additional earthquake records representing near-field and far-field families were utilized to assess the stone bridge sensitivity. The study revealed that far-field earthquakes are far more destructive than near-field counterparts, a finding in full agreement with studies on near field earthquake effects on nuclear structures. The applicability of earthquake damage indicators such as CAV, Arias intensity and energy rate, typically used for conventional and nuclear structures, was evaluated based on the numerical analysis results.
       
  • Shear strength prediction of steel fiber reinforced concrete beam using
           hybrid intelligence models: A new approach
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Zaher Mundher Yaseen, Minh Tung Tran, Sungwon Kim, Taha Bakhshpoori, Ravinesh C. Deo Despite modern advancements in structural engineering, the behavior and design of reinforced concrete beams in shear are still a major concern for structural engineers. In this research, a new Support Vector Regression algorithm coupled with Particle Swarm Optimization (SVR-PSO) is developed to predict the shear strength (Ss) of steel fiber-reinforced concrete beams (SFRC) using several input combinations denoting the dimensional and material properties. The experimental test data are collected from reliable literature sources. The main variables used to construct the predictive model are related to the dimensional and material properties of the beams. SVR-PSO, the objective predictive model, is validated against a classical neural network model tuned with the same metaheuristic optimizer algorithm. The findings of the modeling study provide a clear evidence of the superior capability of the SVR-PSO used to predict the SFRC shear strength relative to the benchmark model. In addition, the construction of the predictive models with a lesser number of input data attributes are attained, leading an acceptable prediction accuracy of the SVR-PSO compared to the ANN-PSO model. In summary, the proposed SVR-PSO methodology has demonstrates an effective engineering strategy that can be applied in problems of structural and construction engineering prospective, applied to predict shear strength of steel fiber reinforced concrete beam using advanced hybrid artificial intelligence models developed in this study.
       
  • Probabilistic evaluation of combination rules for seismic force demands
           from orthogonal ground motion components
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Henry V. Burton, Nilofar Doorandish, Mehrdad Shokrabadi A probabilistic approach to assessing the effectiveness of the rules used to combine demands from orthogonal ground motion components is developed. Full probability distributions of the ratio between the force demands obtained from nonlinear response history analyses using bidirectional loading, which are taken as the “true” demands, and rule-based combinations of the demands from unidirectional loading, are developed. For the percentage combination rules (100-p), a relationship is established between the value of p (e.g. p = 30% for 100–30 rule) and the probability that the bidirectional loading demands exceed the rule-based combination of the unidirectional loading demands. Using this relationship, an appropriate value of p based on an acceptable exceedance probability is determined. The proposed framework is demonstrated using special concentric braced frames with biaxially loaded columns, which are shared by orthogonal braced frames. The combinatorial effect of the orthogonal responses is found to be influenced by several factors including the type of demand parameter (e.g. column axial forces versus stresses), demand level and building height.
       
  • Comparative analysis of numerically simulated and experimentally measured
           motions and sectional forces and moments in a floating wind turbine hull
           structure subjected to combined wind and wave loads
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Chenyu Luan, Zhen Gao, Torgeir Moan Multi-body time-domain finite element models, which implement a recently developed numerical approach for determining forces and moments in floaters, are developed to simulate rigid-body motions and sectional forces and moments of a reference 5-MW braceless semi-submersible wind turbine in turbulent winds and irregular waves corresponding to below rated, at rated and above rated conditions. The simulated responses are compared with measurements of a 1:30 scaled model test using a real-time hybrid testing approach. In general, agreement between simulations and measurements are very good. Differences in spectral densities of the measurements and simulations have been quantified while the reasons for the differences have been thoroughly analyzed and discussed based on comparisons of measurements in different conditions and numerical parametrical study. Effects of non-linear wave excitation loads and drag forces on the rigid-body motions and sectional forces and moments are analyzed while dominant load components in fore-aft bending moments in five cross-sections in the hull of the reference model are identified. The interface between the pontoons and central column of the reference model is identified as the most critical part. Both low frequency and wave frequency load effect should be accounted for. Mean forces and moments from wind and waves result in a change in configuration of mean wetted body surface of the hull when compared to its configuration in calm water. This may result in a considerable change in resultant sectional forces and moments even though change in resultant of the hydro pressure forces on whole of the wetted body surface could be very limited. For the analyzed model, simulated fore-aft bending moments of the model in wind and waves could be obtained by superimposing the results for wind only condition, and wave only condition except that the corresponding averaged wind induced forces and moments should be applied on the numerical model. This simplification can significantly reduce number of cases of short-term analysis required in long-term analysis. However, applicability of the simplification should be analyzed case by case in particular for a blunt structure with relatively large volume of displaced water in waves with relatively small wave length. Analysis and discussions given in this paper are based on available measurements of the model test. Hydroelastisity and structural vibration of the columns and pontoons of the hull are not accounted for by the numerical and experimental models. Suggestions for design of future model tests are given in this paper.
       
  • Load mitigation for a barge-type floating offshore wind turbine via
           inerter-based passive structural control
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Yinlong Hu, Jianing Wang, Michael Z.Q. Chen, Zhihua Li, Yonghui Sun This paper investigates the application of inerter to a barge-type floating offshore wind turbine for the purpose of mitigating loads of the wind turbine structures induced by wind and wave. An inerter-based structural control system, consisting of a parallel connection of a spring, a damper, and an inerter-based network, is proposed. A nonlinear aeroelastic simulation tool for wind turbines called FAST-SC is employed for evaluating the performances of the inerter-based structural control system. Due to the inefficiency of implementing FAST-SC in optimizing the element parameters (spring stiffnesses, damping coefficients, inertances), a time-efficient parameter optimization method is proposed based on a simplified linear design model, where a mixed performance objective function including the tower-top fore-aft deflection and the TMD working space is minimized with respect to the element parameters. It is shown that there exists a tradeoff between the tower-top fore-aft deflection and the TMD working space. Moreover, numerical simulations based on the nonlinear FAST-SC code show that the overall performance can be improved by using an inerter, except the tower-top fore-aft load and the TMD working space. The inerter-based configurations tend to demand more TMD working space than the system with no inerter. Furthermore, it is demonstrated that the overall performance can be improved while maintaining similar TMD working space as the system with no inerter.
       
  • Analytical solution for stiffness prediction of bonded CFRP-to-steel
           double strap joints
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Weijie Li, Elyas Ghafoori, Yiyan Lu, Shan Li, Masoud Motavalli Carbon fiber-reinforced polymer (CFRP) composites have been increasingly used in the strengthening and rehabilitation of steel structures. This paper presents an analytical model for stiffness prediction of CFRP-to-steel double strap joints. Mechanical analysis was performed to determine the shear stress and strain distributions in the bond region, which resulted in deriving a model for stiffness prediction of joints. More than 20 test results from the existing works in the literature were used to validate the proposed model. Results show that the predictions are mostly between 0.8 and 1.2 times the experimental values, with an average error of less than 10%, which demonstrates the effectiveness of the proposed model. Finally, a parametric study with respect to the bond length and the adherend stiffness ratio was performed to give a better understanding of the effect of different parameters.
       
  • Experimental study of rock-sheds constructed with PE fibres and composite
           cushion against rockfall impacts
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Peng Zhao, Lingzhi Xie, Bo He, Yao Zhang To improve the impact resistance of rock-sheds, polyethylene (PE) fibres and expandable polyethylene (EPE) foams are proposed for structural construction. With PE fibres added into the matrix, the ductility and the impact resistance ability of concrete can be enhanced. Moreover, to reduce the dead load and impact load, EPE foam is utilized to replace some sand layers, forming a composite cushion. A series of large-scale rockfall impact experiments were carried out on four prototype models. Under a low- and medium-impact energy, compared to the traditional sand cushion, the composite cushion was more favoured to reduce the impact loading and was more suitable to resist multiple impacts. With the addition of fibres, the integrity of the concrete matrix was improved. The fibre concrete had a better energy dissipation capacity than that of the plain concrete. In addition, more cracks occurred in the plain concrete. When subjected to high energy, the reinforced concrete model was damaged with a large deformation and many fragments. However, the maximum deformation of the PE fibre-reinforced concrete model was very small, and almost no spalling or fragments were found. These results indicate that when constructed using PE fibres and EPE foams, the capability to resist the impact loading of rock-sheds can be significantly improved.
       
  • Critical analysis of ultimate rotation formula for R.C. columns subjected
           to cyclic loadings
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Rosa Fusco, Rosario Montuori, Elide Nastri, Vincenzo Piluso Performance-based earthquake engineering relies on the availability of analytical models that can be used to predict structural performance, including collapse. Current code prescriptions allow evaluating the ultimate rotational capacity of hybrid (mechanical-empirical) or empirical formulations, for R.C. members both seismically and not-seismically detailed. The aim of the present work is to present a critical analysis of the empirical relationship proposed by Eurocode 8 Part 3 and Italian Seismic Code. These relationships formerly similar have been compared with the original formulations introduced by Biskinis and Fardis [1,2]. A databank of cyclic tests on rectangular column sections failing in flexure, shear and flexure-shear, have been selected from an available database and research reports. Their ultimate chord rotation corresponding to an ultimate strength of 80% has been compared with the results provided by the available relationships, to check the accuracy and the reliability of codes proposals. Finally, a new formulation based on an empirical approach is proposed.
       
  • Cyclic behavior of reinforced concrete L- and T-columns retrofitted from
           rectangular columns
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Yu-Chen Ou, An-Nhien Truong An innovative seismic retrofit method was proposed to address the weak first-story issue of reinforced concrete row houses in Taiwan. The proposed method is to turn as-built rectangular columns to L- and T-columns by adding flanges in the weak direction of as-built rectangular columns to strengthen their seismic capacities. The longitudinal reinforcement in the retrofit part of the retrofitted column is not continuous into the beam and foundation above and below the column to ease construction difficulty associated with post-installation of such reinforcement. Large-scale L- and T-columns retrofitted from rectangular columns with the proposed retrofit method were tested in this research using lateral cyclic loading. Test results showed that the retrofitted columns exhibited ductile, flexural dominated behavior. As compared with the original rectangular columns, the proposed retrofit method was effective in increasing the lateral strength of the column. Due to the discontinuity of the longitudinal reinforcement, the retrofitted columns showed lower lateral strengths but less damage and higher ductility than the counterpart monolithic columns. A pushover analysis model was developed for the proposed retrofitted column that accounts for the effects of discontinuity of longitudinal reinforcement in the retrofit part. Comparison of pushover analysis and test results showed that the pushover model generally captured well the force-displacement behavior of the retrofitted columns.
       
  • FE approach to perform the condition assessment of a concrete overpass
           damaged by ASR after 50 years in service
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): R.V. Gorga, L.F.M. Sanchez, B. Martín-Pérez Modeling alkali-silica reaction (ASR) induced expansion and damage in reinforced concrete structures is quite complex, yet necessary to obtain accurate predictions of the structural responses of distressed concrete members. In order to predict the expansion and damage at the structural (macroscopic) scale, a new simple yet reliable finite element (FE) approach was developed and validated by the authors. It accounts for the most important parameters affecting ASR through an engineering-based approach, without the need for non-technical guesses or to “fit” model parameters. In this work, the proposed modelling approach is used to analyze the Robert-Bourassa/Charest overpass (Quebec City, Canada), which was demolished in 2010 due to severe structural distress induced by ASR. Results show that the proposed FE approach is capable of properly performing the condition assessment of the structure at the time of demolition based only on simple measurable parameters, thus proving its applicability to simulate ASR in slender reinforced concrete structures.
       
  • In-plane and out-of plane response of currently constructed masonry
           infills
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Vasiliki Palieraki, Christos Zeris, Elizabeth Vintzileou, Chrissy-Elpida Adami In most of the Reinforced Concrete buildings in Greece, as well as in other earthquake prone countries, the current infill construction, for the exterior walls of buildings, consists in a cavity masonry wall, made of two thin walls. The two walls are not transversely connected. The seismic vulnerability of those enclosures (to in-plane and out-of-plane actions) is high, as many seismic events have shown.In the last decades, emphasis was given to the study of Innovative Infill Systems with improved seismic behaviour. The in-plane and out-of-plane behaviour of the (vulnerable) currently constructed masonry infills has not been systematically studied, experimentally and analytically. Within the present work, two full scale RC infilled frames were tested. One was subjected to in-plane cyclic displacements; the second specimen was subjected to repeated out-of-plane displacements, until severely damaged, and subsequently subjected to cyclic in-plane loading. Hysteresis loops for the entire loading history, the observed damage at several drift values and the overall behaviour of the infill are presented and discussed upon. The obtained results are compared to the results recorded during testing of innovative infill systems. It is shown that the performance of the currently constructed infill system is inferior in terms of both load and deformation capacity.
       
  • Seismic lateral displacement analysis and design of an
           earthquake-resilient dual wall-frame system
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Yulong Feng, Jing Wu, Xun Chong, Shaoping Meng Traditional reinforced concrete shear walls are both prone to damage during earthquakes and difficult to repair after an earthquake. Accordingly, two replaceable buckling-restrained braces (BRBs) are installed at the base of a hinged wall (HW) to form an earthquake-resilient shear wall (HW with BRBs at the base, HWBB). This paper focuses on the seismic analysis and the design of a dual system with an HWBB and a moment-resisting frame (HWBBF). An elastic lateral displacement analysis is conducted for the HWBBFs based on an equivalent continuous model, which consists of a flexural beam with a rotational spring at the base and a shear beam. The strength and stiffness demand formulas of the HW when the frame enters the inelastic stage are approximated based on the results of the elastic analysis. Based on the provided inelastic formulas, an elastic displacement spectrum-based design procedure is presented for HWBBFs to directly determine the sectional area of the BRBs, the required strength and stiffness of the HW. As an example, a 6-story HWBBF is designed using the proposed procedure, and a series of nonlinear response history analyses (NRHAs) are used to validate the procedure and inelastic formulas. The example effectively illustrates the errors associated with the target roof displacement and the formulaic HW demands compared to the corresponding NRHA results, respectively.
       
  • An experimental study on unbonded circular fiber reinforced elastomeric
           bearings
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Pablo Castillo Ruano, Alfred Strauss Seismic base isolation by introducing a flexible horizontal layer at the foundation level of a structure has proven to reduce the seismic demand. Steel reinforced elastomeric bearings have been used for that purpose extensively in the last years. More recently, innovative fiber reinforced elastomeric devices have been investigated as they bring important advantages as reduction of manufacturing and transport costs. The current article analyzes relevant mechanical properties for seismic isolation such as vertical and horizontal stiffness as well as damping capacity in fiber reinforced elastomeric bearings, focusing on the effect of shape geometry and material of the fiber reinforcement layers. Quasi-static cyclic experiments under vertical and combined horizontal and vertical load have been performed in order to investigate the effect of compression, horizontal deflection, frequency of the load and geometrical parameters. Compressive loads up to 12 MPa have been investigated. Moreover, the performance of bearings with round and square plan geometry under multidirectional loading is examined. Comparisons between the obtained results and data from previous works are discussed.
       
  • Detailed numerical research on the performance of unbonded prestressed SRC
           frame beam under vertical cyclic load
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Gangfeng Yao, Xueyu Xiong Prestress tendons can be used to improve the serviceable performance of steel reinforced concrete (SRC) beam members. To have a comprehensive understanding of the seismic behaviors of unbonded prestressed SRC beam members, fifteen frame beam specimens, including thirteen unbonded prestressed SRC ones and two ordinary SRC ones, were designed to make the numerical multi-parameter analysis. The parameters considered were the amount of unbonded tendons, rebar, flange and web thickness of steel shape. In the paper, the load-carrying capacity, strain of steels and concrete, ductility, energy dissipation, deformation restoring capacity, stiffness and strength degradation were detailed analyzed and discussed. The results indicated that increase the amount of unbonded tendons would lower the utilization efficiency of steel and decrease the energy dissipation capacity. Raising the amounts of tendons, rebar or steel shape would reduce the specimen’s ductility and the ductility coefficient had a good linear relationship with the introduced integrate reinforcement index. According to the numerical analysis, several brief design suggestions were provided for reference. Moreover, compared with the ordinary SRC specimens, it could be observed that the energy dissipation capacity of prestressed SRC members was relatively lower, while its deformation capacity was as good as ordinary SRC ones. The application of unbonded tendons in SRC beam members greatly improved its serviceability and deformation restoring capacity.
       
  • A coupled biodynamic model for crowd-footbridge interaction
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Marcelo André Toso, Herbert Martins Gomes Nowadays, there are growing interests in vibration serviceability assessments of high buildings, slabs, metallic and timber structures, and composite footbridges. Indeed, new design trends of composite footbridges make them slender civil structures that may be affected by the load action of walking pedestrians resulting in large deflections or even uncomfortable vibrations. Furthermore, the presence of people on the footbridges cause the addition of mass to the structural system and due to the human bodýs ability to absorb vibrational energy, an increase in structural damping. In this paper, the interaction between pedestrian and structure is modelled using data from pedestrian characteristics and vibration data from a measured footbridge as a comparison basis. The novelty of the papers relies on the proposed new Biodynamic Synchronized Coupled Model (BSCM). It consists in a fully synchronized force model in the longitudinal and lateral direction of pedestrian’s movement and a biodynamic model (with parameters mass, damping and stiffness). This model is coupled to the structural FEM at the feet’s contact points. Pedestrians are treated as individuals with intrinsic kinetic and kinematic parameters following a measured correlation matrix obtained by the use of an especially designed force platform. Finally, the adequacy of the proposed model to represent the pedestrians as BSCM for the walking effects on the structure is investigated by experimentally measured vertical accelerations on a footbridge where two crowd densities, freely walking and synchronism of the pacing rate with continuous crossing are also investigated.
       
  • Large-scale test as the basis of investigating the fire-resistance of
           underground RC substructures
    • Abstract: Publication date: 1 January 2019Source: Engineering Structures, Volume 178Author(s): Limin Lu, Junnan Qiu, Yong Yuan, Jin Tao, Haitao Yu, Hui Wang, Herbert Mang Fire disasters occurring in underground structures generally result in severe damage. In order to investigate the fire performance of typical underground structures, a large-scale fire test on a three-span frame structure was carried out. The tested model was loaded both by vertical and horizontal earth pressures. The applied temperature history, representing the time-dependent fire load, was determined by simulations of fire scenarios in the underground structure with the help of the software FDS. The paper contains test results of the temperature of the air in the furnace, the concrete and the steel bars in the structural model, and the state of deformation of the model. Apparent phenomena, such as cracking and spalling, were observed throughout the whole testing process. The results show that a very dangerous situation of the underground structure exposed to fire may occur during the cooling process. Curling of the top slab was observed during the heating process. More attention in fire-resistance design must be paid to the columns. The fire test results are useful for validation of numerical models and for further fire-resistance research of underground structures.
       
  • Thermo-mechanical stability analysis of functionally graded shells
    • Abstract: Publication date: 1 January 2019Source: Engineering Structures, Volume 178Author(s): M. Rezaiee-Pajand, D. Pourhekmat, E. Arabi In this paper, the thermo-elastic nonlinear analysis of various Functionally Graded (FG) shells under different loading conditions is studied. A second-order isoparametric triangular shell element is presented for this purpose. The element is six-noded, and each node has all six independent degrees of freedom in space. It should be added, the first-order shear deformation theory is induced. Furthermore, Voigt’s model is adopted to define the FG material properties, which are considered to change gradually from one surface to another. The critical temperature is predicted. Both the pre-buckling and post-buckling equilibrium paths are traced. Since the linear eigenvalue analysis leads to wrong responses in the problems with strong nonlinearity, the suggested procedure is performed based on the FEM and more exact estimations are achieved using equilibrium path.
       
  • Performance evaluation of existing isolated buildings with supplemental
           passive pseudo-negative stiffness devices
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Meng Wang, Fei-fei Sun, Hua-jian Jin A new configuration for passive pseudo-negative stiffness device (PPNSD) is proposed to work as a supplemental device for the seismic protection of existing isolated buildings. The proposed PPNSD reproduces the hysteretic behaviors of semi-active pseudo-negative stiffness devices (PNSD). Using the ratchet-pawl mechanism, a prototype was realized and tested under cyclic loading, validating the feasibility of the proposed PPNSD. Seismic reduction effect of the PPNSD on single-degree-of-freedom (SDOF) systems was verified through seismic response analysis. The PPNSD shows superiority in suppressing the peak acceleration response of long period structures, which is unlikely to be achieved even with large supplemental damping. Then, the performance of isolated buildings with PPNSD was evaluated in comparison to those of isolated buildings with traditional passive isolators under far-field (FF), near-fault pulse-like (NFP), and near-fault non-pulse-like (NFNP) ground motions. It is shown that the use of PPNSD not only simultaneously reduced the base drift and the acceleration of superstructures, but also was effective for all the FF, NFNP, and NFP motions.
       
  • Seismic-induced collapse simulation of bridges using simple implicit
           dynamic analysis
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Tzu-Ying Lee, Wen-Hsiao Hung, Kun-Jun Chung A simple implicit dynamic analysis method is extended to simulate the seismic-induced collapse of bridges. Nonlinear and discontinuous behaviors, such as material yielding and cracking, member damage, separation, falling and collision with other members, are considered in the analysis. An impact model with a contact detection scheme is developed to consider the impact response between beam elements representing bridge superstructures. Multiple-support excitation is considered. The Matsurube Bridge which collapsed in the 2008 Japan Iwate-Miyagi inland earthquake due to not only strong ground excitations but also the sliding of the rock mass beneath the bridge is analyzed for verifying the effectiveness of the analysis method. By reproducing the in-situ collapse situation, the failure mechanisms of the bridge are estimated. The results demonstrate that the simple implicit dynamic analysis is robust in simulating the collapse of bridges that exhibit highly nonlinear and discontinuous behaviors under extreme earthquakes.
       
  • Generic 3D formulation for sliding isolators with variable curvature and
           its experimental verification
    • Abstract: Publication date: 15 December 2018Source: Engineering Structures, Volume 177Author(s): Liang-Wei Wang, Lyan-Ywan Lu Sliding isolators with variable curvature (SIVCs), whose isolation stiffness can be continuously varied along with isolator displacement, allow a passive isolation system to adapt to seismic excitations. The variable stiffness also has the advantage of mitigating the long-period resonance effect when the isolation system is subjected to ground motion with strong long-period components. However, most previous studies on SIVCs were theoretical and adopted simplified models that omit the tri-directional coupled motion due to the geometric effect of the concave sliding surface. In order to provide a more precise analytical tool, this study developed a set of three-dimensional formulas based on Lagrange’s equation of motion to predict the complete dynamic forces of an SIVC system transmitted to the superstructure. The formulas, which are applicable to all types of axially symmetric SIVCs, were then verified experimentally using a shaking table test that involved an SIVC system consisting of four polynomial friction pendulum isolators (PFPIs). The derived formulas show that the horizontal and vertical forces of the SIVC include two high-order nonlinear terms related to the curvature and slope of the SIVC sliding surface. In conjunction with the three-dimensional sliding motion of the isolator, these high-order terms cause the tri-directional coupling effect. The experimental results of the shaking table test verified the presence of this dynamic coupling effect and validated the proposed analytical model. Using the isolator parametrical values obtained from the test, the peak responses of the PFPI system subjected to 165 sets of bidirectional horizontal ground motions with various intensity levels were simulated. The simulation results indicate that the high-order coupling terms have a limited influence on isolator drift, but have a notable effect on the shear and vertical forces of the PFPIs when the motion of the isolation system is enlarged by increased seismic intensity.
       
  • Corrigendum to “Modelling one-way out-of-plane response of single leaf
           and cavity walls” [Eng. Struct. 167 (2018) 241–255]
    • Abstract: Publication date: Available online 20 September 2018Source: Engineering StructuresAuthor(s): U. Tomassetti, F. Graziotti, A. Penna, G. Magenes
       
 
 
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