Abstract:Ambient vibration tests of a frame structure formed by the main building and podium without seismic joint were conducted and dynamic characteristics of the structure were analyzed. The sensors employed for the tests were instrumented on the right and left stairwells, the fourth floor of the main building and the large span floor of the podium with grillage beams. With the tested acceleration data and improved frequency domain decomposition method, modal parameters of five modes were identified. Identification results from different tests are approximate. Variations of identified natural frequencies are smaller than those of damping ratios. The first four modes are induced by the vibrations of the main building. The fifth mode is the first vertical bending mode of the podium. Torsional behavior appears in the first three modes due to asymmetry of the structure. The spurious modes during identification may be due to dynamic interactions of the main building and podium. Finite element model of the tested structure was constructed and five modes were obtained, which agree well with the identification results. Influence of different connection forms between the main building and podium on the natural frequencies and mode shapes of the structure were analyzed. Results show that fixed or pinned connections between the main building and podium have almost no influence, while presence of seismic joint has large influence on the natural frequencies of the structure. The order of the mode shapes does not change for all the cases.
刘佩1,2,连鹏宇1. 基于环境振动测试的框架结构主裙楼动力特性分析[J]. 振动与冲击, 2016, 35(10): 174-179.
LIU Pei1,2, LIAN Peng-yu1. Dynamic characteristics analysis of a frame structure with the main building and podium based on ambient vibration test data. JOURNAL OF VIBRATION AND SHOCK, 2016, 35(10): 174-179.
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