Collapse Simulation Of The Serial Isolation Structure Of Laminated Rubber Bearing With RC Column Under Multi-Component Near-fault Earthquake

In the far-fault area, the good effect of shock absorption of base-isolated structure with LRB is widely accepted. It being applied to near-fault area is natural thoughts. With building site in our country is increasingly strained, more and more building may have constructed the basement. Combining these factors, as a result of many of the serial isolation structure, which consists of laminated rubber bearing mounted on top of basement column. In the earthquake, the main reason of threatening people's life and the property security seriously is that the collapse of building. At present, it hasn't been researched deeply that according to the particularity about response characteristic, failure factors, collapse mode of the serial isolation structure under near-fault earthquakes. Therefore, base on serial isolation structure as objects, near-fault ground motion as input, this paper study according to the particularity about response characteristic, collapse mechanism, effectively prevent collapsed measures of the serial isolation structure. Major work has the following respects:(1) Introduce the basic characteristics of near-fault ground motion, including the concentration of near-fault strong ground motions, the surface rupture and fling-step, the rupture directivity effect, the near fault large velocity pulse and the hanging wall effect, and effect on the structure. The research status of the serial isolation system, which consists of laminated rubber bearing mounted on top of basement column. The difficult point and basic means of collapse process simulate of structure.(2) Established analysis model of the serial isolation structure, which consists of laminated rubber bearing (LRB) mounted on top of basement column. Comparative analysis seismic response of the serial isolation structure by near-fault earthquake and far-fault earthquake, and considering soil-structure interaction (SSI), analysis isolation effect and character. Analysis shows that the serial isolation with preferably isolation affect in near-fault earthquakes, but the displacement response in near-fault larger than far-fault earthquakes. As the soil become soft, considering the influence of the near-fault and SSI gradually increasing, especially the effect of soil four significant increase.(3) Analyzed in comparison that the influence of structural seismic response in different earthquakes wave and different slenderness ratio, when with and without link beam which on top of basement column. Summarize the influence law of link beam to structural seismic response. It turned out that the link beam to the influence of structural response is minimal.(4) Under great earthquake, collapse simulation of the serial isolation structure and non-isolated structure when bottom column is weak. If isolated structure with weak bottom column under near-fault earthquake are more likely to happen collapse for column failure than no isolated structure.(5) Simulate LRB damage by wrote user subroutine of MSC.MARC, the user subroutine is UACTIVE that birth-death element program. Kill the elements which are linked together with LRB spring once the maximum shear force or axial force maximum reaches the limit.(6) In order to control displacement of the isolation layer under great earthquake, guard against structure collapse for exaggerated displacement of the isolation layer, install nonlinear dampers in the isolation layer. Probe into dynamic time history analysis the serial isolation structure. It is have good results for control displacement of the isolation layer.(7) Install multi-level variable stiffness limiting displacement in isolation layer of the series isolation structure, and give collapsed simulation to the series isolation structure. Analysis the collapse characteristic, the structure of the collapse that process started in ground floor. When design should be appropriate consideration strengthen in the bottom of the structure. In addition, set the multi-level variable stiffness limiting displacement, can effectively preventing whole collapse of structure caused by the isolation layer failure because of excessive displacement, increase in structure collapsed ductility, created the precious time for reduce casualties and property losses.