ABSTRACT
The superstructure of skewed bridges is more likely to have large in-plane displacement during the earthquake. By casting the girder and the abutment monolithically and form the skewed integral abutment bridges (SIABs), earthquake damage to the bridge could be expected to be effectively reduced, but abutment-soil interaction and abutment pile-soil interaction need to be considered during bridge seismic design and analysis. There is a lack of studies investigating overall bridge performance of SIABs when subjected to seismic loads. In order to study the critical seismic response of skewed integral abutment bridges (SIABs), the East Montpelier Bridge was taken as the prototype, and bridge models were established with the SAP2000 software. The strength interaction function of steel H-pile and the judging criterion of critical seismic response of SIABs was suggested. Nonlinear time history analysis was conducted with different skew angles and input angles of seismic excitation under bi-directional earthquake actions. Result indicates that: the input angles of ground motions has great influence on the internal force response of the abutment piles, and increasing the input angle of ground motion will increase the plastic development of the piles. The application of four paired bidirectional input ground motion SX + 0.85SY, SY + 0.85SX, SX - 0.85 SY and SY - 0.85SX is proposed to simplify the critical seismic response analysis of SIABs, which has highly analysis accuracy within 3% relative error.
