Seismic Response of Bridges Subjected to Different Earthquake Types Using IDA

Abstract

Incremental Dynamic Analysis (IDA) was used to evaluate the seismic response of straight, continuous 4-span bridges with different sub-structure configurations. Three different record sets were chosen to represent three different earthquake types which can occur for a site such as Vancouver (i.e., crustal, subduction interface, and subduction inslab earthquakes). Seventy eight records were considered in each set (i.e., a total of 234 records) and the capacities of the bridges were evaluated using a fast IDA algorithm. A simplified method to account for the effects of spectral shapes was used. Different subsets of the records with specific characteristics were also used in the IDA. The bridges were designed and evaluated for two different design force modification factors and bridges with different degrees of irregularity were studied. Comparisons of the IDA results obtained indicated that in most of the cases the interface record sets resulted in lower median collapse capacities and hence were the most critical of the ground motions studied.

Keywords:

• Incremental Dynamic Analysis (IDA)
• Subduction Earthquakes
• Crustal Earthquakes
• Spectral Shape
• Epsilon
• Bridges
• Regularity

Acknowledgments

The financial support provided by the Natural Sciences and Engineering Research Council of Canada for the Canadian Seismic Research Network is gratefully acknowledged. Ground motion data for Japanese earthquakes were obtained from the K-NET and KiK-NET databases at www.k-net.bosai.go.jp and www.kik.bosai.go.jp and other crustal ground motion data obtained from the PEER-NGA database available at http://peer.berkeley.edu Data on Japanese earthquake records was provided by Dr. Katsuichiro Goda.