Study Of AP1000Turbine-Generators Foundation Seismic Performances

To study dynamic characteristics of a spring vibration isolated turbine-generator foundation, a test model was designed and fabricated in this article to the scale of1:8. Then each mode and the corresponding frequency of the foundation were get by three-dimensional three-point excitation method. Afterward, finite element method was used in modal analysis of the foundation, which proved that the computed result was in good agreement with the test result. For further study of the influence on foundation self-vibration frequency caused by vibration isolated springs, finite element method was further applied to analyze the self-vibration characteristic of the same foundation but without vibration isolated springs. According to the analysis result, natural vibration frequencies of the foundation was adjusted effectively by using vibration isolated springs.By comparison between natural frequencies of foundations with and without springs combined with seismic influence coefficient curve in code for seismic design of buildings, vibration isolated springs can affectively reduce responses in horizontal earthquake action.Afterward, pseudo-dynamic test of the foundation model was finished. In this article foundation model was applied seismic action in3working condition. Time-history curves of accelerated speed, speed and displacement of the foundation top plate was tested. According to these data, reacting force-displacement hysteresis curve was get in order to energy-dissipation ability in reciprocating load. At the same time, displacement time-history curves of column bottom, beam-column joints and the bottom plate were tested. Based on this, interlayer displacement angle of the structure was calculated to judge if it meets regulatory requirements.For another, in great earthquake plastic hinge can ensure enough energy-dissipation ability. However, too large displacement will result in local failure and even collapse of the whole structure. Because of this, positions of these plastic hinge are important. In nonlinear state, positions of cracks are often the positions of plastic hinge. So crack development was in the end of this article for analysis.