Dynamic behavior of seismic-excited bridges in ultimate states

T. Y. Lee, P. L. Wong, R. Z. Wang

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

This study is aimed to predict the ultimate situation of bridges with or without unseating prevention devices through numerical analysis. In the past extreme earthquakes, a number of bridges suffered damage with unseating of the superstructures. Therefore, it is full of curiosity that how large earthquake will cause a bridge to collapse and how the ultimate state will be. It is extremely difficult to conduct a shaking table test by using a proto-model, especially for multi-span or long-span bridges. The Vector Form Intrinsic Finite Element (VFIFE) is superior in managing the engineering problems with material nonlinearity, discontinuity, large deformation, large displacement and arbitrary rigid body motions of deformable bodies. In this study the VFIFE is thus selected to be the analysis method. Once reaching the ultimate state, a bridge undergoes progressive failure, fragmentation and collapse. Structural elements enter nonlinear material range and/or exhibit large geometry nonlinearity even rigid body motion. The analysis methods in VFIFE for sliding of structures and fracture of elements are herein introduced to predict the collapse mechanism of bridges. Three types of bridges, a six-span simply-supported bridge, a continuous-span bridge with hinge and roller bearings and a continuous-span bridge with highdamping- rubber isolators, are analyzed. The input ground motion was recorded at JR Takatori station in 1995 Japan Kobe earthquake. The ground acceleration varies from 100% to 300% at an increment of 10%. Through numerical simulation of three bridges with or without unseating prevention devices, the ultimate states are demonstrated and compared. The results show that the unseating prevention devices do not increase the safety of the studied bridges as expected. It is interesting to observe that the simply-supported bridge suffers unseating of the superstructure under much lower ground motion than the continuous-span bridge with rigid bearings. The continuous-span isolated bridge suffers unseating under lower ground motion than the simply-supported bridge. Also, the results confirm that the VFIFE is a powerful computation method to simulate the failure mechanism of devices and structural elements so as to successfully predict the ultimate states of bridges.

Original languageEnglish
Title of host publication9th US National and 10th Canadian Conference on Earthquake Engineering 2010, Including Papers from the 4th International Tsunami Symposium
Pages1766-1774
Number of pages9
StatePublished - 2010
Event9th US National and 10th Canadian Conference on Earthquake Engineering 2010, Including Papers from the 4th International Tsunami Symposium - Toronto, ON, Canada
Duration: 25 Jul 201029 Jul 2010

Publication series

Name9th US National and 10th Canadian Conference on Earthquake Engineering 2010, Including Papers from the 4th International Tsunami Symposium
Volume3

Conference

Conference9th US National and 10th Canadian Conference on Earthquake Engineering 2010, Including Papers from the 4th International Tsunami Symposium
Country/TerritoryCanada
CityToronto, ON
Period25/07/1029/07/10

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