Study On Dynamic Characteristics Of Lead Rubber Bearing And Its Application In Steel Structure

According to statistics,China is a country with the most earthquakes on earth.33%of the world earthquakes have happened in China.At the same time,since the 21st century,the economic of development speed is very fast in China,especially in high-technology industry.Considering the precision instrument,the demand of the seismic performance of high-rise steel structure building is higher and higher.In this paper,the lead rubber bearings are used to study the seismic isolation effect of the structure.And during the study,the acceleration and velocity are used as the main control indexes.The results are compared with the national standard of vibration equipment.And it shows that the seismic isolation can effectively reduce the damage to the instrument.It is found that the way testing equivalent stiffness of the bearing is not strictly in accordance with the national standard.It is also found that the frequency of the bearing loading displacement is different from the national standard in seismic isolation and the technique of laminated rubber bearings standard.At the same time,it is also known that the frequency of bearing loading displacement is also different.This paper is going to conduct the dynamic time analysis on a domestic precision instrument manufacturer's seven-layer storage of steel frame under one-directional earthquake ground motion with the finite element software Abaqus and Midas/Gen.The paper researches the structural vibration reduction and its rules of base isolation,and also by the test of equivalent stiffness of lead rubber bearing,explores the influence of the horizontal loading displacement frequency on abutment property.This includes the following aspects:(1)Inputting the seismic waves in such situations which makes the angle and Z axis into 0°,15°,30°,45°,60°,75°and 90° respectively.Taking the structural vertex displacement and story drift as control measures,the research tries to find the worst angle is 90° when the seven-layer storage of steel frame is putting under one-directional earthquake ground motion.(2)Making lead rubber bearing's horizontal displacement frequencies of 0.1 Hz,0.2 Hz,0.3 Hz,0.4 Hz and 0.5 Hz respectively to explore the influence of the horizontal displacement frequency on the mechanical parameters,such as equivalent horizontal stiffness,bearing energy dissipation and equivalent damping ratio,etc.It is found that in a certain range of allowable error,the change of the frequency has little effect on the equivalent level stiffness,bearing energy dissipation and equivalent damping ratio.It can basically be treated as the same.(3)The paper studies the seismic reduction effect of the steel frame loaded with the isolation bearing.It is found that by setting the lead rubber bearing,the structural acceleration and velocity between the floors can be effectively reduced,thus the damage of precision instruments can be decreased,to achieve the purpose of isolation.(4)Finally,the paper explores the effect of the structure isolation when changing the equivalent stiffness of the lead rubber bearing.The results show that the changing of the bearing level equivalent stiffness can greatly affect the structure shock absorption.The increase of equivalent stiffness will cause the increase of the floor acceleration and speed,which is not conducive to the anti-seismic property of structures.