Experimental Studies on Seismic Performance of Rigid-frame Extradosed Cable-stayed Bridges

With the aim of further understanding the seismic performance of extradosed cable-stayed bridges, this paper presents an experimental investigation of a three-pylon rigid-frame extradosed cable-stayed bridge by conducting 1/20 scaled longitudinal shake tables model tests at the laboratory of Tongji University, Shanghai, China. The design, construction and testing protocol of the test model are firstly introduced. Observation of the seismic damage situation and empirical data on the seismic responses of the test model are then provided. The test results show that: (1) severe seismic damage appeared at the bottom and upper parts of piers and damage at the bottom parts were much heavier; (2) no damage was observed on short pylons; (3) structural stiffness degradation occurred when PGA≥0.4g; (4) the vibration of the short pylon almost has no contribution in the displacement at the pylon top.