DEVELOPMENT OF FRAGILITY AND RELIABILITY CURVES FORSEISMIC EVALUATION OF A MAJOR PRESTRESSED CONCRETEBRIDGE

摘要

Bridges in recent earthquakes have proven to possess the most threat to transportation system duringand after earthquakes. In addition, well being of bridges plays a major role in the post earthquakeemergency structures for earthquakes. To address the physical aspects of the seismic performance ofbridges, fragility functions or damage probability matrices are developed and used for evaluationpurposes. These fragility curves represent the probability of structural damage due to various groundshakings. And more so they describe a relationship between ground motion and level of damage. In thispaper, fragility and reliability curves are developed. The seismic vulnerability of a prestressed concreterailway bridge then is assessed based on developed relations. These relations are derived from dynamicnonlinear finite element analysis. A software package in MATLAB is also generated for easy study of theresults. Important aspects of this study are; modeling of bridge using 3D nonlinear models and modelingof abutments, bearings, effect of falling of girder on its bearings and nonlinear interaction of soil-structureaction. Reliability curves developed in this study are unique in its case. This paper presents the method aswell as the results in the form of vulnerability and structural reliability relations based on two damagefunctions.