ISSN (PRINT): 2393-8374, (ONLINE): 2394-0697, VOLUME-4, ISSUE-12, 2017 9 SEISMIC FRAGILITY ANALYSIS OF DAMAGED CONCRETE BRIDGE- A PERFORMANCE BASED APPROACH D. M. Patil 1 , Amit Melani 2 , Rakesh K. Khare 3 1 Department of Civil Engineering and Applied Mechanics, Shri Govindram Seksaria Institute of Technology and Science, Indore (M. P.), India Abstract Recent earthquakes and the resulting losses have highlighted the structural design inadequacy of important structures like concrete bridges to carry seismic loads. Hence there is a necessity of performance based procedures in seismic design code for assessment of concrete bridges in terms of seismic resistance. In view of this, best suited methodology and guidelines are very much necessary for seismic evaluation of existing bridges and also for design of new bridges. Therefore, in present study, seismic fragility analysis of concrete bridge damaged during 1995 Kobe Earthquake has been carried out using SAP2000 for pushover analysis and IDARC-2D for incremental dynamic analysis with two sets of time histories, to insist on performance based earthquake engineering procedure. Keywords: concrete bridge, evaluation, fragility, seismic. I. INTRODUCTION Current codes and modern engineering practice address the issues of collapse prevention and life safety by conservatively predicting nominal demands and strengths of structural members, but provide little indication of the actual state of a structure after an earthquake. In post earthquake condition, a bridge may still be standing but structural and nonstructural members may be damaged, resulting in costly repairs. The economic losses due to downtime may even be larger. In contrast to current codes, performance-based earthquake engineering (PBEE) attempts to explicitly predict damage states and assess the probability of reaching multiple levels of damage. PBEE has the potential to improve structural engineering practice by providing engineers the capability of designing structures to achieve a variety of performance levels. The impact of implementing PBEE goes beyond improving engineering practice and extends to a wide range of decision making. The potential impact of PBEE is summarized in Pacific Earthquake Engineering Research Center’s report [1]. In this paper, existing results of Hanshin Expressway damaged during Hyogo-ken Nanbu Earthquake of 17 January 1995 [2] are used to match the results of fragility analysis. The drift-ratio approach provides a simple means of estimating damage displacements (which is essential to engineering practice), but it has significant limitations. This approach neglects the effects of cycling on damage and it is difficult to implement for columns with biaxial bending, variable axial loads or variable shear spans. The objective of this paper is to evaluate column-modeling strategies that are capable of accurately modeling column behavior under seismic loading, including global and local deformations, as well as progression of damage. The focus of this research will be on ductile reinforced bridge columns, for which shear failure is not a consideration. Seismic fragility analysis of damaged concrete bridge has been carried out using SAP2000 and IDARC-2D to establish importance of PBEE. SAP2000 is used for pushover analysis and IDARC-2D [3] is used for incremental dynamic analysis using two sets of time histories.