Effect of the Plasticity of Piping and Support Structures on the Seismic Response of Piping Systems

This study describes the results of seismic analyses conducted to clarify the effect of the plastic deformation of a pipe and its support structures on the seismic response of the entire piping system. The first type of analyses includes the investigation of plasticity with regard to the following parameters: (1) none, (2) piping, (3) support structure, and (4) piping and support structure. The second type of analyses includes the parametric survey of the yield load and post-yield stiffness of the restoring force characteristics of support structures. The results of the first type of analyses have demonstrated significant implications on the seismic design of piping systems based on the elastic-plastic response analysis. First, the piping response, i.e., elbow strain, is significantly reduced when plasticity is considered in the piping support. On the contrary, the piping support response is not so much affected by the piping plasticity. The results of the second type of analyses showed that the yield load of the support structure significantly affects the response of the piping system, whereas the post-yield stiffness does not affect much compared with the yield load.