ABSTRACT
Real-time hybrid simulation is an efficient testing method for investigating the seismic response of a structure. Unlike slow hybrid simulation, it can effectively account for the rate-dependency of structures by imposing the target displacement on an experimental specimen in a real-time manner. It is well known that concrete structures have a rate-dependent behavior due to the viscoelasticity of the bulk of the concrete and the rate process of the breakage of bonds in the fracture process zone. The rate-dependency can cause the difference in the response of concrete structures, depending on the imposed velocity on the structures. Therefore, it is important to include the rate-dependency effect to understand better the seismic behavior of concrete structures.
In this study, the rate-dependency effect of a reinforced concrete pier is experimentally investigated through the slow and real-time hybrid simulations. The concrete pier is used to support a two-span bridge. The nonlinear response of the bridge under earthquake loads is accurately accounted for by physically testing the concrete pier in a laboratory, while the bridge deck is analytically modeled. A dynamic servo-hydraulic actuator is connected to the top of the pier to transfer the inertial force of the bridge deck to the pier. Prior to conducting hybrid simulations, cyclic load tests for the concrete pier are conducted with a predefined displacement history at different displacement rates. Then, a slow hybrid simulation and a real-time hybrid simulation are conducted to investigate the rate-dependency effect on the seismic response of the concrete structure. The results from these hybrid simulations are provided and discussed along with the observation from these tests. Figure 1 illustrates one of test results of this study. Comparison of shear force vs displacement relationship of the pier (SHS=slow hybrid simulation; RTHS=real-time hybrid simulation). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig207_1.tif"/>
Figure 1. Comparison of shear force vs displacement relationship of the pier (SHS = slow hybrid simulation; RTHS = real-time hybrid simulation).
