Study On The Influence Of Lead Heart Rubber Support On The Isolation Effect Of Frame Structure

In recent years,due to frequent domestic large and small earthquakes,in terms of protecting life and property,the buildings with base isolation is more and more popular.At present,there are many different types of lead core rubber bearings on the market,to help the designer to shorten the preparation time for the preliminary design scheme of the isolation structure,this thesis selects GZY500-V6 A,LRB500 and LRB500-100,which are widely used by scholars at home and abroad,using ANSYS to analyze the established basic isolated and non-isolated seven-layer frame structure models,respectively,the scheme of the framework structure with good isolation effect is optimized,the specific process and conclusion are as follows:(1)Scheme 1(GZY500-V6A),scheme 2(LRB500)and scheme 3(LRB500-100)are 1.16～2.87 times more than the vibration period of scheme 4(non-isolation)structure.analysis the self-vibration period of the three basic isolation schemes,the smaller the vertical stiffness of the lead center,the larger the self-vibration period,and the maximum of the vertical stiffness of 1600 k N/mm.(2)The displacement analysis of different schemes shows that the maximum displacement of the non isolated structure occurs at the top floor,and the maximum inter story displacement of the isolated structure occurs at the isolation floor.In multiple earthquakes,the displacement angle of seismic superstructure decreases to17.7%～51.4% of non-seismic buildings;in rare earthquakes,the displacement angle of seismic superstructure decreases to 12.3%～43.7% of the non-insulated building.The isolation structure is much smaller than the non-isolation structure,which shows that the isolation plays a good role in the inter-layer displacement angle.(3)The acceleration of each scheme increases gradually from bottom to top,with the highest acceleration at the top,but the acceleration of the floor of the base-isolated structure is significantly smaller than that of the non-isolated structure.Among them,under multiple earthquakes,the top-level acceleration average of scheme 1,scheme 2and scheme 3 compared to scheme 4 is reduced from 216.50cm/s~2 to 76.261cm/s~2,88.019cm/s ~2,88.150cm/s ~2 respectively;in rare earthquakes,the average top-level acceleration value of scheme 1,scheme 2 and scheme 3 compared to scheme 4 is reduced from 1745.3cm/s~2 to 475.53cm/s~2,431.03cm/s~2,433.63cm/s~2 respectively.(4)The vertical stiffness parameters and the forward bending stiffness parameters of the lead-center rubber support in scheme 2(LRB500)are optimized.In the case of rare earthquakes,the inter-layer displacement angle of scheme 2 is reduced by 0%～2%compared with scheme 5,it can be concluded that the vertical stiffness parameter has little influence on the inter-layer displacement angle;Under rare earthquakes,the inter-layer displacement angle of scheme 2 is reduced by 15%～20% compared with scheme 6,it can be concluded that the forward bending stiffness parameter has a great influence on the inter-layer displacement angle.The smaller the forward bending stiffness parameter of 1280 k N/mm,1448 k N/mm and 1880 k N/mm is smaller,but after the forward flexion stiffness parameter reaches 1280 k N/mm,the smaller forward flexion stiffness parameter is increased.