Abstract：Considering the irregular geometry, stiffness and mass distribution, the critical angle of seismic incidence for curved bridges is investigated. Allow for the yield condition for concrete structure under axial compression and bi-axial flexural moments being well depicted by the Bresler Yield Surface, the most vulnerable direction for piers is therefore defined as the critical angle of seismic incidence. Upon having the seismic response from two orthotropic directions by response spectrum analysis, a new algorithm is proposed in which multicomponent ground motion and correlation of natural vibration modes are considered. Further more, procedures for time history analysis are developed. Finally a worked example of a closed circular ramp is given to illustrate the validity of the method.
2013, Vol. 32 
