A simplified analytical model for U-shaped steel dampers considering horizontal bidirectional deformation

Hysteresis steel dampers are widely used in earthquake-resistant structures, where some of them are anisotropic and capable of sustaining earthquake-induced bidirectional deformation. In this paper, a simplified analytical model is proposed for simulating the hysteretic behavior of U-shaped steel dampers with horizontal bidirectional deformation. The proposed model is composed of a series of shear springs with different nonlinear characteristics in a radial configuration, and the Menegotto-Pinto hysteresis model is employed to represent the hysteretic characteristics of the springs. The mechanical and shape-related parameters of the hysteresis model are set according to the multi-directional deformation characteristics of steel dampers. With the aim of validating the effectiveness and applicability of the analytical model, a U-shaped steel damper was used as an example. The pseudo-static hysteretic characteristics of the steel damping element were analyzed and the elasto-plastic seismic response of a curved bridge featuring a steel hysteresis device was investigated. The results showed that the proposed model is sufficiently accurate to simulate the hysteretic behavior of U-shaped steel dampers, and thus provides a practical method to assess U-shaped steel dampers through seismic response analysis.