A new computational platform for damage-index-based reliability assessment of bridges in conjunction with finite element analysis

Abstract

In this paper, a new computational platform was developed to evaluate the reliability of bridges under earthquakes based on a recently proposed damage index. Bridge safety is important for the sustainability of a transportation network, and bridge failure can lead to significant economic losses. To prevent such failures and ensure network reliability, seismic fragility curves are often derived. These curves assess the probability of structural failure during seismic events considering uncertainty factors such as material properties. To obtain a seismic fragility curve, both finite element analysis and reliability analysis tools are required. Although several platforms were developed based on this notion, seismic fragility curves derived by use of such an existing computational platform is limited to the outcomes of the software in charge of finite element analysis. However, such an approach may fail to capture the complex nonlinear behavior of materials subject to a seismic excitation. Recently, attention has shifted to using a sophisticated damage index, which can account for nonlinear material behavior. To use the damage index for seismic fragility assessment, in this study, Reinforced Concrete Analysis in Higher Evaluation System Technology (RCAHEST) was introduced. By integrating RCAHEST with a MATLAB-based reliability program, Finite Element Reliability Using MATLAB (FERUM), the FERUM-RCAHEST platform was developed. During the FERUM-RCAHEST analysis, RCAHEST performs finite element analyses about a reinforced concrete (RC) bridge column to evaluate damage index values as output, while FERUM repeatedly calculates RCAHEST based on probabilistic variables to come out the damage probability of the bridge. Through this comprehensive approach, the proposed platform successfully evaluated the reliability of RC bridge columns with time-varying corrosion levels, demonstrating its effectiveness and applicability for the seismic fragility assessments of bridges considering corrosion.