Bidirectional Nonlinearity Computational Analysis And Research On Relevant Parameters Of Isolation

As a seismic technology, base isolation technique plays a major role in numerous engineering practice. Various theories about base isolation have been gradually improved in the research of domestic and foreign scholars. However, research about the non-linear characteristics and related seismic response of leaded isolation is still more limited in the response under unidirectional force. In order to make the base isolation method of calculation and design can adapt to the case of high damping, bidirectional earthquake and seismic response of a two-way coupling, research on bidirectional nonlinear characteristics of base isolation and the calculation method of base isolation system in bidirectional nonlinear seismic response is very necessary and urgent.On the basis of analyzing several common restoring force model isolated structure way of restoring force model isolated structure on the analysis, this article summarizes the relevant characteristics and limitations and make improvements, gets the calculation model of bidirectional nonlinear single particle seismic response considered under horizontal force coupling. Compared the result of earthquake response between unidirectional and bidirectional, linear and nonlinear, calculations show that the results of acceleration response and displacement response of isolated structures in high damping are quite different between bidirectional linear and bidirectional nonlinear.To be able to meet the designed computing requirements, this article adopts bidirectional nonlinear structural model and associated calculation methods to calculate the yield-gravity ratios of high damping isolation system under the bi-level excitations in rare earthquake of 8 degrees, 8.5 degrees, 9 degrees. This article establishes the correspondence bi-directional acceleration and displacement response spectrums at different fortification intensity. And according to the current "standard" displacement limits put forward reasonable reference value of yield-gravity ratios.On the bidirectional nonlinear constitutive relation of isolation bearing, establishing the earthquake response calculation method of multi-degree of freedom seismic isolation system response, and applying Benchmark model to the earthquake action calculation under bidirectional earthquake. This article calculates three different vibration period of the isolated system under the same premise of corresponding yield-gravity ratios. The results show that the upper structure displacements and bearing displacements have slightly different but still within reasonable limits of the corresponding isolation systems between single particle isolation system and Benchmark model in rare earthquake of 8 degrees, 8.5 degrees, 9 degrees. Therefore, verifying the effectiveness and the reliability of the single-particle model. Applying all the reasonable yield-gravity ratios which obtained by single particle model in several seismic intensity to Benchmark model,and the result shows that it also able to better meet the displacement limits, so as to provide a reasonable reference for isolated isolation bearing product design and structural design way.