Shaking table testing of a reinforced concrete frame retrofitted with a steel oval member equipped with rubber cylinders

Abstract

In this study, an innovative retrofitting approach for existing reinforced concrete (RC) frames against near-fault earthquakes is proposed. The proposed approach is implemented by strengthening the portal RC frame with a steel oval hollow member equipped with several rubber cylinders. This approach not only fulfills the basic mechanical requirements for a RC frame subjected to earthquake forces but also possesses the benefits of good constructability and retains an unobstructed opening between columns. To verify the feasibility and effectiveness of the proposed retrofitting method, a series of shaking table tests were conducted to compare the seismic performance of the RC frame before and after retrofit. A near-fault ground motion recorded during Taiwan Chi-Chi earthquake is scaled to different intensity levels and adopted for the shaking table tests. The test results show that the proposed retrofitting approach can not only recover but also upgrade the seismic capacity of the earthquake damaged RC frame. In fact, no obvious damage was observed on the retrofitted frame even after the experiment based on the Chi-Chi near-fault ground motion amplified with a factor of 180% was completed.