Study On Seismic Performance Of Multi-level Energy Dissipation Posttensioned Prestressed Steel Segmental Assembled Pier

Segmental piers have been shown to be effective in speeding up bridge construction and minimizing traffic disruptions.Because of the poor seismic performance of this structure,its application in seismic area is limited.In this paper,a multi-stage energy dissipation method for post-tensioned prestressed segmental piers is presented.The main research work of this paper is as follows:(1)the system components of post-tensioned segmental piers with multi-stage energy dissipation are introduced.The mechanical behavior of multi-level energy dissipation post-tensioned prestressed segmental piers under lateral load is divided into two stages: pre-decompression stage and post-decompression stage.The mechanical behavior of the prestressed tendons post-compression is described.An iterative moment-curvature analysis method considering the stress variation of prestressing and energy-dissipating reinforcing bars is presented.The corresponding force-displacement curve is solved on the basis of bending moment-curvature analysis.(2)the influence of tensile recovery stiffness,compressive recovery stiffness and damage factor on the hysteretic behavior of concrete is analyzed.The results of calculating the damage factor by different methods are compared.The numerical analysis model of prestressed segmental piers is established,and the calculated results are in good agreement with the test data.(3)the multi-stage energy dissipation segmental piers are simulated,the failure mode is analyzed,and the energy dissipation principle is expounded.It is revealed that the essence of multi-stage energy dissipation is to continuously reduce the seismic force at the weakest point of Segmental pier system.The effect of energy dissipation reinforcement and prestressed reinforcement on the performance of segmental pier system is studied.The multi-stage energy dissipation method has better seismic performance than the energy dissipation device only installed at the bottom section of the pier.