Research On Seismic Isolation Of Rubber Bearings With Relative Rotation Between Upper And Lower Surfaces In String Truss Structure

Since the Economic System Reforming and opening,the country's economic development needs have driven the rapid development of the construction industry.Nowadays,the largespan spatial structure is one of the key development forms of the civil engineering industry,and the tensioned string truss structure is one of the representative large-span spatial structures.The structure is mainly composed of truss chords,various braces and prestressed steel cables.The structure has the advantages of reasonable forcing distribution and large span space.It is widely used in practical projects.Its safety under earthquake is more important than other building structures.As a commonly used support type in seismic isolation design,rubber isolation bearings are increasingly used in large-span spatial structures.However,the complicated stress state of the spatial structure and external factors will make the rubber isolation bearings during the actual use of the seismic support,the upper and lower surfaces of the support rotate relative to each other,that is,the support generates a rotation angle.At this time,the mechanical properties of the rubber isolation support will inevitably change,which will affect the isolation effect of the structure and the performance of the support.Use it yourself.In order to study the effect of the rotation angle of rubber isolation bearings on large-span space-isolated seismic structures,this paper selects the actual project Guangzhou International Conference and Exhibition Center as a case study,its structural form is a string-string truss structure,and uses the large-scale general-purpose software ANSYS for finite element simulation Combined with the mechanical performance test of rubber isolation bearings,the impact of rubber isolation bearings with different initial angles on the isolation effect of the string-string truss is emphasized,and it is hoped that it can provide a reference for the isolation design of the stringstring truss structure in the future.The main research contents and conclusions of this thesis are as follows:(1)The seismic isolation technology and its development and current status in large-span spatial structures and string-string truss structures is introduced.(2)The mechanical performance test is performed on the rubber isolation bearing,and the influences of the vertical pressure of the bearing and the rotation angle of the bearing on its mechanical properties are analyzed.The focus is on the effect of the rotation angle on the horizontal mechanical properties of the bearing after the rotation of the rubber isolation bearing.Impact,in which the upper and lower surfaces of the rubber isolation bearing are rotated by a specific test device to generate a corner.The test results show that within the engineering force range,the external vertical pressure has almost no effect on the mechanical properties of the bearing;and the angle of the bearing has a greater impact on the horizontal mechanical properties of the bearing,within the allowable deformation of the bearing(0.02rad).The horizontal rigidity of the support decreases as the angle of rotation increases.(3)Taking Guangzhou International Convention and Exhibition Center as a case,the finite element software ANSYS was used to analyze the tension of the string truss under different degrees of prestress loss(0?100%),and the analysis showed that the angle of the support increased with the prestress loss increased;according to the test data of the support,the seismic time history analysis was performed on the structure with the isolated support with different rotation angles.The results showed that as the rotation angle of the support increased,the vibration amplitude of the structure increased,and the support itself the horizontal deformation was also getting larger.When the rotation angle was 0.01 rad,the displacement of the left end of the truss exceeded the specification limit,and some of the supports fail,which is not conducive to structural isolation.(4)After studying the influence of the tension of the string truss on the angle of the rubber bearing,considering the influence of the external natural temperature on the angle of the bearing,the analysis shows that the angle of the bearing increases as the temperature increases;Timehistory analysis of structures with different corners of isolated bearings under the influence of temperature,the results show that: considering the temperature effect,the angle of the bearing has a greater impact on its use,and the horizontal deformation of the isolated bearing increases with the increase of the angle While increasing.When the rotation angle of the support is 0.0075 rad,the displacement of the support at the right end of the truss exceeds the limit,and some of the supports fail;when the rotation angle is 0.01 rad,the displacement of the support at both ends of the truss exceeds the limit,and all the supports fail,which is not conducive to structural isolation.