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Innovative method in seismic design of slab-on-girder steel bridges

Lotfollahi, M ; Sharif University of Technology | 2008

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jcsr.2008.01.017
  3. Publisher: 2008
  4. Abstract:
  5. Most slab-on-girder steel bridges have been designed and constructed without seismic resistance consideration; as a result, their members, connections, and more commonly their substructure are not sized and detailed to provide the required ductile response needed during major earthquakes. A ductile seismic retrofit solution proposed in this investigation consist of converting of existing end diaphragms into ductile end diaphragms and replacing the end cross-frames and the lower lateral-braced panels adjacent to the supports by special ductile diaphragms. Consequently, this creates ductile fuses to protect the rest of the super- and substructure. This paper illustrates the typical seismic retrofitting of such bridges. It also presents a model governing transverse seismic response of retrofitted bridges by simplified analytical models of the end diaphragms. For three types of ductile diaphragm devices such as Eccentrically Braced Frames (EBF), Triangular-plate Added Damping and Stiffness Devices (TADAS) and Chevron Knee Bracing (CKB), finite element nonlinear analytical models are developed in separate flexural and shear yielding modes, and the capability of the proposed finite element models is ascertained. A methodology to determine overall stiffness and strength of such ductile diaphragms based on an innovative algorithm is established to determine the nonlinear behaviour of the proposed systems, using all active parameters of such system in the form of nondimensional chart and graphical approach. Static and dynamic analysis in elastic and inelastic range are conducted to verify the capability of the new proposed systems for the retrofitting design purpose, which can developed a new design step-by-step calculation procedure for each ductile device. The capability of the effective performance based design method, which can significantly enhance seismic performance of slab-on-girder steel bridges, is ascertained through the two different example problems using all ductile diaphragms. © 2008 Elsevier Ltd. All rights reserved
  6. Keywords:
  7. Beams and girders ; Braces (for limbs and joints) ; Bridges ; Dynamic analysis ; Finite element method ; Maintenance ; Nonlinear optics ; Retrofitting ; Seismic design ; Seismology ; Static analysis ; Steel ; Steel bridges ; Stiffness ; Structural analysis ; Active parameters ; Added damping and stiffness ; Analytical modelling ; Bridge ; Chevron knee bracing ; CKB ; Cross-frames ; Design procedure ; EBF ; Eccentrically braced frames ; Effective performance ; Finite element ; Finite element modelling ; Graphical approach ; Innovative methods ; New design ; Non-linear behaviour ; Nondimensional ; Nonlinear analysis ; Overall stiffness ; Retrofit ; Seismic performance ; Seismic resistance ; Seismic retrofitting ; Shear yielding ; Slab-on-girder ; Static and dynamic ; Step-by-step algorithm ; TADAS ; Transverse seismic response ; Diaphragms
  8. Source: Journal of Constructional Steel Research ; Volume 64, Issue 12 , 2008 , Pages 1420-1435 ; 0143974X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0143974X08000114