Experimental Methods For Seismic Performance Of Thin-Walled Stell Structures And Its Equipment Design

In recent years,with the increase in the demand for dense storage and the frequent occurrence of earthquakes around the world,the stability and safety of thin-walled steel structures have become increasingly prominent.Different from the structure of the building,the storage racks in the dense storage environment has structural features such as large opening,thin-walled,porous,high softness.Considering the complex working environment such as earthquake movement,cargo slip,equipment collision,the stability a nd reliability of high-rise dense thin-walled steel structures face higher technical challenges.At present,the analysis of rack system stability in China is mostly limited to static analysis.The dynamic characteristics of the whole rack are not consider ed.The industry lacks corresponding test evaluation methods and test devices.Therefore,based on the Shanghai Engineering Center Capacity Improvement Plan(17DZ2283800)and the Shanghai Municipal Science and Technology Commission Standard Construction Project(15DZ0500400),this paper is based on thin-walled steel structure test and finite element analysis,and comprehensively applies tribology,elastoplastic mechanics and seismic engineering analysis.The method is applied to study the friction performan ce of thin-walled steel storage racks structure and the seismic performance under the condition of friction.It provides reference for the seismic standard and engineering application of domestic thin-wall steel storage racks structure.The main work carried out in this paper includes:(1)Referring to the EU shelf seismic design specification,the standardization test method of beam tray friction was studied,the design of the corresponding friction slip test device was completed,and the friction pair slip test was carried out.Based on the statistical data of average friction coefficient and coefficient of variation,the effects of beam tray type,dry and wet conditions and centroid offset on the friction coefficient test were analyzed.The results show that the friction coefficient of the wooden pallet and the painted beam is the largest,and the friction coefficient of the steel pallet and the galvanized beam is the smallest.The effect of humidity on the friction test is much greater than the effect of cargo eccentricity on the friction test and is greater than the influence of the cargo core on the friction test.This provides a standard friction test recommendation for beam trays.(2)Take multi-storage racks as an example,a shelf dynamics simulation model considering the sliding friction of the beam tray is established,using time history analysis method,taking the maximum displacement,layer shear force and interlayer displacement angle as the evaluation indexes,the influence of the frictional slip of the beam tray on the dynamics of the racks under different types of earthquakes is analyzed.The results show that the seismic analysis results of the shelf model along the roadway direction are more conservative than the vertical roadway direction.Taking high-rise racks as an example,when a rare earthquake occurs above the REN(Class 6.5),it is necessary to evaluate the seismic performance of the bottom,top and second floors of the high-rise steel storage racks.(3)The finite element numerical simulation is used and the existing pseudo-dynamic test methods are compared according to the evaluation indexes such as interlayer displacement angle and displacement ductility coefficient.The results show that the elastoplastic pseudo-dynamic test results are more conservative,which is conducive to the seismic safety design of the racks.Based on the Push-over analysis method,the different loading methods in the elastoplastic pseudo-dynamic test are comprehensively analyzed,it is found that the elastoplastic pseudo-dynamic test method that implements the uniform distribution mode and the inverted triangle distribution method has more safety evaluation value in the process of seismic performance analysis.On this basis,the overall design of the pseudo-dynamic testing device for steel structure shelves is completed.