Damage Analysis Of Base-isolated Structure Considering Foundation Uneven Settlement

The base-isolated technology as one of new type and effective seismic methods has been advocated by many civil engineer s which has been widely used in modern building structures.All previous seismic actions show that th e base-isolated structures have a good aseismic and shock absorption effect and can reduce economic losses and casualties in the affected areas greatly.In the western of China,a large number of collapsible loess are distributed which caused by soil itsel f features tend to be foundation uneven settlement occurred in the upper structure deformation,cracking,tilt,and even collapsed,these problems are eag er to be solved in civil engineering field.T he influence of foundation uneven settlement to the upper structure has caused wide public concern.Now scholars,in nation and abroad,mainly from the perspective of internal force and deformation to analyze the influence of foundation settlement to base-isolated structure with factor of beams bearing capacity and deformation and ignoring the energy dissipation of the structure under earthquake which cannot reflect the real earthquake damage.In this paper adopts double standards of deformation and energy floor maximum damage index for quantitative indicators and according to the related performance level threshold to study the infect of foundation uneven settlement to base-isolated structure by non-liner finite element software Perform-3D based on energy balance principle.T he specific work as described below:(1)Based on the principle of energy balance,building the settlement structure and non-settlement structure by Perform-3D first then do the dynamic time history analysis of both structures to study the energy import,distribute and dissipate of foundation uneven settlement to base-isolated structure.(2)Citing double parameters damage model of deformation and energy,using non-liner finite element software Perform-3D to do dynamic elastic-plastic time history analysis of uneven settlement structure an inta ct structure.Calculating damage index of component level such as beam and column according to the relevant standards and get damage index of each story.Using the maximum floor damage index for quantitative indicators do es vulnerability analysis of upper structure.T hen taken the quantitative indicators of isolation layer displacement to establish a structure vulnerability curve and analyze the overall damage of base-isolated structure.(3)Studying the influence of different settlement value to upper str ucture.Using IDA method and concerning the influence of settlement value 10 mm,20mm,30 mm,40mm,50 mm,60mm to base-isolated structures from the point view of isolation layer displacement,the maximum story displacement angle and the maximum damage index of floors.