Comparison of Two Dimensional Nonlinear Analyses of Integral Abutment Bridge and Simply Supported Bridge Under Near Fault Earthquake Loading With Consideration Soil Structure Interaction

Bridges form important link in the transportation system of a country. Bridges are also considered to be structures of post earthquake importance because of their need for emergency response, relief and rehabilitation measures. It is known from experience that bridges are vulnerable to earthquake damage. Thus the safety and protection of bridges in earthquake is utmost important. There are a number of bridges which are designed according to old codes when modern seismic provisions were not developed. Such bridges are mostly found deficient and may need seismic retrofitting. The occurrence of large earthquakes close to fault is inevitable and one kind of bridges that needs more investigation is integral-abutment bridge. This paper presents results of two-dimensional nonlinear analysis of integral abutment bridges under near fault earthquake loading. The analyses were performed on a nonlinear dynamic finite element (FE) model using the computer program PLAXIS. Near fault earthquake acceleration records with various amplitudes of velocity pulses were used as input ground motions in the analyses. The results of the analyses indicate that the input motions with strong velocity pulses may cause excessive displacements of the bridge super structure and abutments. The objective of this research is to investigate the response of the integral abutment bridge to a near field earthquake loading taking into account the soil-structure interaction effects and compare with simply supported bridge. Further study is needed to investigate the effects of strong velocity pulses on overall response of a integral abutment and fully understand the dynamic behavior of an integral bridge.