PUSHOVER ANALYSIS OF A PRESTRESSED CONCRETE CONTINUOUS RIGID-FRAME BRIDGE WITH BOX-TYPE HIGH PIERS

In this paper, a prestressed concrete continuous rigid frame bridge with the span arrangement of 50+90+50 m and two piers of 56 and 60 meters high was selected as the engineering background. Both the transverse and the longitudinal seismic properties of the pier as well as the whole bridge were analyzed by Pushover analysis method. The plastic hinges introduced in the Pushover analysis was adopted based the double broken line model obtained from pseudo-static test of the 1/14 scale high pier models. Both the inertia force distribution and the modal force distribution were adopted. In order to account for the effects of higher modes, the modal Pushover analysis procedure was carried out. Furthermore, the Pushover analysis results were compared with those from nonlinear dynamic time-history analysis, and the seismic capacity of the bridge was evaluated according to Guidelines for Seismic Design of Highway Bridge (Guidelines) in China. The main conclusions listed as follows: (1) The results from Pushover analysis where the multi-stage combination of vibration modes were considered agree well with those from elasto-plastic time-history analysis. (2) The seismic capacity of the selected bridge meets the requirements of 8 degree fortification under the E1-level earthquake action specified in Chinese seismic guidelines. Under the E2-level earthquake action, the maximum displacement exceeds its yield displacement, and is still within the limit displacement.