Dnyanraj M. Patil Journal of Engineering Research and Application www.ijera.com ISSN : 2248-9622 Vol. 8, Issue 10 (Part -II) Oct 2018, pp 15-22 www.ijera.com DOI: 10.9790/9622-0810021522 15 | Page Seismic Evaluation Of T-Girder Concrete Bridges- A Performance-Based Approach Dnyanraj M. Patil * , Rajesh Bhargava ** and Rakesh K. Khare * *(Department of Civil Engineering and Applied Mechanics, SGSITS, Indore, M. P., India **(Rajiv Gandhi Proudyogiki Vishwavidyalaya, Bhopal (M.P), India Corresponding Author: Dnyanraj M. Patil ABSTRACT:In Indian structural codes, Performance-based earthquake engineering (PBEE) methodology has not been implemented yet. It is widely developed during the past two decades, and has become a key approach for seismic analysis and design in most developed countries. Therefore, further research is required to develop a domestic approach for Indian applications. In this paper, the seismic capacity of a typical T girder concrete highway bridge designed as per Indian Standards is evaluated througha probabilistic method as well as nonlinear static analysis (pushover analysis). Two different types of substructures, single-column and multi-column bents are considered separately. Fragility curves are developed and used for evaluation purposes. This paper presents the method as well as the results in the form of vulnerability and structural reliability relations based on two damage functions. Keywords: concrete bridge,damage limit state, evaluation, fragility curve, incremental dynamic analysis -------------------------------------------------------------------------------------------------------------------------------------- Date Of Submission:02-10-2018 Date Of Acceptance: 13-10-2018 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION Considering the high randomness of return period and shaking intensity of earthquakes, they remain one of the most unpredictable natural hazards. In response to this, the extensive research on performance-based approaches in structural engineering during the last two decades has brought about the invention of performance-based earthquake engineering (PBEE) methods. However, as discussed by Cornell and Krawinkler (2000), it should not be forgotten that PBEE methods are not essentially developed for predicting structural performance or estimating seismic losses; they are established to ultimately contribute to the effective reduction of seismic losses and improvement of structural safety [1]. It is known that the seismic performance of transportation systems plays key role for the post earthquake emergency management [2]. Hence, it is necessary to be evaluated both physical and functional aspects of bridge structures. The physical aspects of the seismic performance of bridges are evaluated with the seismic fragility functions. A fragility curves represent the probability of structural damage due to various ground shakings [3,4]. They describe a relationship between ground motion and level of damage. In this paper, the seismic performance of a typical six span T-girder concrete highway bridge is studied. For this purpose, a three-dimensional analytical model of the bridge is created, which encompasses all the bridge major components. It is noteworthy to mention that this analytical model was developed for generalised concrete T-girder bridges and not for a specific bridge. The bridge is first analysed using nonlinear static analysis (pushover analysis) by SAP2000 [5] for substructure type of single-column and multi- column bents separately. The seismic performance and overall seismic capacity of the bridge are then investigated through incremental dynamic analyses (IDA) by developing IDA curves [6] using IDARC2D software [7]. Nonlinear dynamic analysis is applied to simulate the earthquake loads over the analytical model. A set of ten Indian ground motions is selected. Fragility and hazard survival curves are generated to define the damage limit states and probability of survival of the structure. II. GEOMETRIC DESCRIPTION AND DESIGN DETAILS In this study typical Indian T-girder six span concrete bridge is considered with span length of 24m. The bridge is analysed using nonlinear static analysis (pushover analysis) by SAP2000 for substructure type of single-column and multi- column bents separately. Both substructure types are designed as per provisions of IS 456, IS 1893 and IS 13920 for 1.5(DL+EQ) i.e. load of 5500kN acting at C.G. of bent cap. Finite element model for both the bridges with different substructure types are shown in figure below. For abutments and RESEARCH ARTICLE OPEN ACCESS