STUDY ON DYNAMIC CHARACTERISTICS OF RC FRAME DURING DAMAGE AND REHABILITATION PROCESS

A 1/4-scale two-bay eight-storey reinforced concrete frame was tested on shaking table.After the initial shaking table test,the damaged frame was repaired using epoxy injection technique,and then subjected to the same acceleration record input selected for the initial tests.The variations of dynamic characteristics were investigated experimentally,such as the natural frequency and the damping ratio throughout the whole process by micro-tremor test,impact test and white noise test.The test result indicated a characteristic decrease of natural frequency and an increase of structural damping in the damage process,while the situation was opposite in the retrofitting process.Compared with the initial test,the decline of natural frequencies and the growth of damping ratios were smaller in subsequent test.According to the response of the frame in two shaking table tests,the dynamic characteristics have close relationship to the seismic resistance capability.With the variation of the dynamic characteristics,the earthquake resistance capability of damaged/repaired frame can be predicted effectively.