SEISMIC ANALYSIS OF MULTI-SPAN CONTINUOUS REINFORCED CONCRETE RIGID-FRAME ARCH-BRIDGE

The paper analyzed the seismic behavior of a reinforced concrete rigid-frame arch bridge which collapsed in Wenchuan earthquake using the spectral analysis method, the elastic dynamic analysis method and the elasto-plastic dynamic analysis method. According to the two-stage aseismic principle, 3 natural ground acceleration records and 1 artificial record were selected. The results show that: due to its structural complexity, the vibration frequencies of the multi-span continuous rigid-frame arch bridge are close to each other, and the modal participation mass is widely separated. Structural inter-forces and plastic rotation of RC section become larger when considering the soil-pile-structure interaction. The asymmetric longitudinal displacement of the foundation changes the vibration characteristics of the structure, and substantially increases the inter-forces and plastic deflections of main and minor arch legs on the foundation with weaker horizontal stiffness. The study may give a reference to seismic performance evaluation of multi-span continuous rigid-frame arch bridges.