Seismic response analysis of the precast double-deck rocking frame bridge pier system

摘要

To improve seismic performance of double-deck frame bridge system, a novel precast double-deck rocking frame bridge pier system is developed based on ductile and rocking seismic conception design in this paper. In this novel system, the upper columns are allowed to rock between the precast cap beams to form the rocking story, while the lower columns are connected to precast cap beam and footings by grouted splice sleeve to form emulative cast-in-place story. The seismic response of this novel frame bridge pier system is investigated. Nonlinear equations of motion of the system are established following Lagrange's equation and conservation of angular momentum, and the analytical model is used to conduct case study, parametric study and stability analysis. The results show that seismic responses of the lower columns of the proposed structural system are smaller than cast-in-place bridge pier, while it has an opposite trend for upper columns. The effect of deformability of the lower story on the stability of the system is marginal for low-frequency pulses or small column size, while for high-frequency pulses or large column size the deformability jeopardizes the stability of the system.