RC arch bridge seismic performance evaluation by sectional N-M interaction and coupling effect of brace beams

摘要

Reinforced concrete (RC) arch bridges usually sustain remarkable damage from strong earthquakes. To comprehensively investigate the seismic performance of an RC arch bridge, a benchmark RC arch bridge was modeled with the ABAQUS software, and the seismic performance in the longitudinal and lateral directions was determined at different earthquake intensities. In this paper, the seismic responses, i.e., the mid-span drifts, plasticity development, and N-M interactions at the springing, etc., are discussed. The sectional safety factor is proposed to quantitatively describe the damage degree of the springing section under longitudinal excitation. According to the results, this factor successfully indicated the damage status at the springing, and was consistent with the strain development and the N-M interactions. With regard to the lateral excitation, the current design did not consider the contribution from the brace beams. The coupling ratio (CR) is proposed to quantitatively calculate the coupling effect on the two arch ribs from the brace beams. Different CRs were tested to enhance the lateral seismic performance. Finally, the recommended CR was derived.