Dynamic Response Analysis Of Irregular Story Isolation Structure Under The Near Field Earthquake

Story isolation technology is evolved from the practice of the base isolationtechnology. As a new type of isolation, damping technology, the story isolationtechnology is a complement of base isolation technology; what’s more it has animportant significance for the development and promotion of the isolationtechnology. In the far-field region, the seismic response of the story isolationstructure can be reduced significantly. However, the seismic response of this kind ofstructure under the near-field earthquake with a significantly larger peak andlong-period velocity pulse movement is still a lack of systematic research. Therefore,this paper studies the seismic response of the story isolation structure near the faultzone to explore the seismic response characteristics and explain some earthquakedamage characteristics.The three different forms of structural numerical model (the traditionalanti-seismic structure, the base isolation structure and the story isolation structure)are established by the software SAP2000which is the integrated software forstructural analysis and design. Firstly, the static nonlinear method (Pushover) wasused to analyze the three different structures. By this method, the seismic response ofthe structures can be approximately predicted, and the result of the analysis can beused as a basic data for the further analysis. Then, by the basic data of the staticnonlinear analysis, the structure models are re-adjusted, and the structural parametersof the final computing models are determined, and what’s more, the time historyanalysis of the seismic wave is selected to adjust. Finally, the calculated results to thedifferent structures of the modal analysis and the dynamic time-history analysis arecompared with.By the analysis above, the following conclusions can be obtained. For theisolated structure and seismic structure with a podium, the shear near the top ofpodium is significantly larger than the other layers, should be strengthened in thissite in the structural design. Because of the velocity pulse movement of thenear-fault earthquake, the seismic response at the top story of the structure areamplified, it shows that the larger pulse component of the near-fault earthquake isthe main factors for the earthquake damage. Compared with the seismic structure,the seismic response of the upper structure in the isolated structure is significantlyreduced. Compared with the story isolation structure, the damping rate of the baseisolation structure is much bigger; it means that the base isolation structure has abetter damping effect. Without the special requirements, the base isolation structureshould be preferred to use.