Research On The Mechanical Properties Of Seismic Supports And Hangers And Their Structural Improvements

As a kind of Non-structural building components,the anti-seismic support and hanger are part of the electromechanical piping system.IN addition to fixing various electromechanical piping equipment,it also protects them during earthquakes and can effectively control the occurrence of secondary disasters.As the seismic supports and hangers have Not been widely used for a long time,there is Not much research work on their mechanical properties and component improvements.This dissertation classifies and summarizes the seismic supports and hangers,and compares and tests the seismic supports and hangers of three manufacturers;and based on the analysis of finite element software,studies the stress state of the seismic supports and hangers under horizontal load.Structural improvement plan;at the same time,the fatigue performance of seismic conection members is studied,and the influence law of loading system and lifting length on the cyclic loading performance of seismic support and hanger components is summarized.Through the research of this dissertation,the following conclusions are obtained:(1)The failure modes of components mainly include:C-shaped channel steel and channel steel Nut internal tooth failure deformation,U-shaped pipe clamp internal shrinkage deformation,and hinged seismic connection component cracking or breaking at the bend.The analysis results based on the finite element software also show that when the components are subjected to a horizontal load,the stress is mainly concentrated on the internal teeth of the C-channel steel and the channel steel Nut,the U-shaped pipe clamp,the bend of the hinged connecting member,and the lower end of the screw.The situation in the experiment is the same.(2)Proposed an improvement plan for the structure:1)The screw should be 5.8 grade with a diameter of Not less than 14 mm to ensure that the screw has excellent deformation resistance while avoiding fracture;2)The optimal tooth profile of the C-channel steel and channel steel Nut internal teeth Tooth height 1.5 mm and tooth width 1.5 mm;3)Redesigned a New type of seismic connection member that can effectively avoid cracking and stress concentration;4)Redesigned a New type of pipe clamp with better anti-deformation performance.(3)During installation and use,the two-hole parts of the seismic connection member are more concentrated and more vulnerable than single-hole parts.When the confidence level is 0.9,the tensile strength interval of the double-hole parts is 210.47 MPa to 263.2 MPa;when the confidence level is 0.95,the tensile strength interval of the double-hole parts is 204.79 MPa to 268.89 MPa.When the specified double-hole part is loaded with 106 cycles,the median fatigue limit is 19.56 MPa.The obtained S-N curve reflects the law of fatigue life of the double-hole parts of the seismic connection member.(4)In the loading process with displacement as the control condition,it is difficult to define the criterion for the cyclic loading performance of seismic support and hanger components.The loading process hardly affects the cyclic loading performance of the components.When the seismic support and hanger components of the same mass are loaded during the Malhotra loading process,the Number of loading cycles of the limit displacement decreases with the shortening of the hoisting length.The shorter the hoisting length of the seismic support and hanger is,the better the anti-deformation performance in the horizontal direction.It is recommended that the hoisting length in the actual project is Not more than 600 mm.