Hybrid testing of capacity designed RC structural walls for the determination of nonlinear seismic shear amplification

Hybrid testing is an effective experimental method to study the dynamic behavior of structural elements under various types of loads. The hybrid testing method enables the seismic responses of large structural elements to be reproduced, such as the responses of reinforced concrete (RC) shear walls in a laboratory environment without needing to include the large masses typically encountered in multistory buildings. In this study, a test specimen corresponding to the base plastic hinge zone of an eight-story RC structural wall was tested in a laboratory environment, whereas the remainder of the wall was modeled numerically to evaluate the seismic shear amplification due to nonlinear higher mode effects. A method is presented for controlling three degrees of freedom of a specimen with high axial stiffness and high lateral stiffness at the beginning of the test and the substantially reduced stiffness after cracking and yielding of the specimen. Because the duration of an uninterrupted test would have been very long, a method was used to stop and restart the test at will so that the whole test could be performed over several days. Seismic shear amplification due to nonlinear higher mode effects in a structural wall with yielding occurring at the base is measured for the first time in a hybrid test . The test results clearly present seismic shear amplification that is larger than building codes recommended values.