A new design method for double-deck bridge bents was proposed to achieve seismic damage control.This method incorpor-ates a rocking self-centering(RSC)structure for the upper-floor piers,while the lower-floor piers remain non-rocking.Additionally,steel-tube grout dampers(SGDs)are used to enhance the energy dissipation capacity of the joints.Numerical analysis models for the seismic behavior of the SGD and the RSC bent with SGD were developed using the OpenSees platform,and their accuracy was verified by comparing them with test data.Seven near-fault ground motions were selected,and incremental dynamic analysis(IDA)was conduc-ted to study the seismic behavior of the bent.The study results indicate the following:(1)When the peak ground acceleration(PGA)is 0.1 g,the SGD yields and dissipates energy.(2)At a PGA of 0.4 g,the maximum deformation of the SGD is only 53.44％of the nomin-al ultimate maximum deformation,and the maximum stress of the unbonded prestressing tendons is 59.60％of their nominal yield strength.(3)When the PGA reaches 0.8 g,the SGD is close to rupture,and the maximum stress of the prestressing tendons is 84.78％of their nominal yield strength.Compared to steel angles,SGDs exhibit greater deformation and energy dissipation capacity and are less prone to rupture damage under strong earthquakes.
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