Progressive Collapse Analysis of Cable-Stayed Bridges
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TECHNICAL ARTICLE—PEER-REVIEWED
Progressive Collapse Analysis of Cable-Stayed Bridges Arash Naji . Mohammad Reza Ghiasi
Submitted: 10 April 2019 / Accepted: 16 April 2019 / Published online: 2 May 2019 Ó ASM International 2019
Abstract Several codes have proposed guidelines to prevent progressive collapse. Although most of these standards are in progress, few recommendations for progressive collapse analysis and design of cable bridges or even bridges can be found. In this paper, progressive collapse analysis of a cable-stayed bridge is investigated. In this regard, the effects of changes in Fy, E and cross-section area of cables to progressive collapse resistance are studied. The evaluation is performed by alternate load path method and the nonlinear time history tool in SAP2000V17 software. The results of the analysis show that as the cross section and the modulus of elasticity of the cables increase, displacement of bridge decreases and the bridge’s resistance increases against failures. Also, for the case where Fy of cables were increased, displacement of the bridge did not differ, and only the formation of the plastic hinges in the cables changed. Keywords Cable-stayed bridge Progressive collapse Capacity curve
Introduction To prevent progressive collapse, abnormal loads should be considered in the design of structures. Progressive collapse is a structural failure that is initiated by localized structural damage and subsequently develops, as a chain reaction, into a failure that involves a major portion of the structural A. Naji (&) M. R. Ghiasi Sadjad University of Technology, Mashhad, Iran e-mail: [email protected] M. R. Ghiasi e-mail: [email protected]
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system. As the action is initiated by a release of internal energy due to sudden member failure, progressive collapse is a dynamic phenomenon. This member loss disturbs the initial load equilibrium of external loads and internal forces, and the structure then vibrates until either a new equilibrium position is found or the structure collapses [1, 2]. Following the approaches proposed by Ellingwood and Leyendecker [3], the design guidelines [4–6] define the following methods for structural design of buildings to mitigate damage due to progressive collapse: the tie force method (indirect design), the specific local resistance method (direct design) and the alternative load path method (direct design). Although in the tie force method the ties between the structural members ensure structural integrity in a quantitative manner, Abruzzo et al. [7], Yi et al. [8] and Naji [9] demonstrated that the current TF method is inadequate for progressive collapse design. Different simplified procedures for simulating the effects of progressive collapse can now be found [10–19]. However, the work in this area introduces primarily to buildings. Recent experiences, like the collapse of the I35 W deck truss bridge [20, 21] in Minneapolis, Minnesota, acquire keen priority of the need to integrate progressive collapse into the design of bridge structures. Je
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