Seismic response of cable-stayed bridge subjected to single-support excitation on various soil condition

Department of Civil Engineering., Andalas University, 25163 Limau Manis, Indonesia

^* Corresponding author: masrilayanti@eng.unand.ac.id

Abstract

For cable-stayed bridge, pylon and girder are one of the most important factors in the design process. Because of the length this structure, it needs to consider the type of the soil because different soil type can be resulting a different earthquake loads. In this study, the behavior of superstructure was investigated using time history analysis subjected to excitation uniformly on the pylon and girder. The test model was a cable-stayed bridge which classified as a long-span bridge. For obtaining the effects of soil type condition, different response spectrums are considered for three soil types: firm, medium, and soft soil. The response spectrums were thus converted to become ground acceleration time history and displacement time history. The displacement was then applied longitudinally and transversally to the supports of the structure to determine the behavior of the bridge. The result shows that the maximum displacement on the pylon and girder due to longitudinal load was at the top of the pylon and in the middle of the main span. As for the transverse earthquake load, the maximum displacement was in the middle area of the pylon and the middle of the main span. The results also defines that the displacement caused by firm soil is smaller than medium soil and soft soil.