Study On Influence Of Material Damping On Seismic Responses Of Reinforced Concrete And Concrete-Filled Steel Tube Structures

Damping, the parameter characterizing the energy dissipation in structural vibration, is one of the important factors affecting the dynamic response of structures. As there are different mechanisms contribute to energy dissipation in the real structures, it is hard to obtain an uniform understanding about damping. For analyzing the real structures, the damping values are usually considered as constants or using Rayleigh damping instead of. The method to calculate the damping as a constant based on the material used in the structure ignores the other structure factors and is not reasonable. The Rayleigh damping is only set up for decoupling in computation without clear physical meaning. The complex damping which considers the influence of stress and amplitude changing on energy dissipation is more reasonable in calculating the structural vibration.In this paper, introducing the stress related complex damping model into the structural dynamic equation and utilizing the Finite Element Method, the responses of a Reinforced Concrete (RC) frame and a Concrete-Filled Steel Tube (CFST) arch bridge suffered the El Centra wave, the Tianjin wave and the Northridge wave are calculated, and the way to analysis the complicated structure with the stress related complex damping model is realized. The results indicate that the predictions of the seismic responses based on vary damping models are different, and the material damping of structures is a variable based on the structural stress. For the RC frame, the responses based on the stress related complex damping model are higher than that of the viscous damping model, and the amount of the material damping in the structural damping is increasing with the structural stress. For the CFST arch bridge, the responses based on the stress related complex damping model are also higher than that of the viscous damping model, and the amount of the material damping in the structural damping is increasing with the structural stress too. The influences of the concrete strength and the steel ratio on the seismic responses of the CFST arch bridge are also considered.