The Ultimate Bearing Capacity Of Fastener Type Steel Pipe Scaffold Structure Influence Analysis Based On Measured Imperfection

As a temporary structure, scaffolding structure use has become an indispensable a part ofthe hot construction industry. In different kinds of scaffolding structures, steel tubular scaffoldstructure is in a dominant position because of its simple set-up, low cost, low requirement for site,high bearing capacity.Steel tubular scaffold is a truss structure used is sensitive to defect structure and system, andstructure steel pole is a long-term repeated use, there is the cumulative effect of wall thickness ofwear and tear, the initial bending of the specification provided, but after repeated use of realisticpipe defects measured and statistical analysis have not been reported. Not yet formed a unifieddefect analysis theory and methods, the use of safety to ensure that the steel tubular scaffoldstructure to carry out the observed defects in the structure and properties of the impact study hasimportant theoretical significance and value in engineering.The article is based on fault tree analysis, the establishment of fastener scaffold safetyaccident of the fault tree diagram, analyze the structure importance of the basic events havecaused the crash, it can provide certain reference value to prevent the accident. According toshan’xi registration level of construction enterprise qualificationsa and the practical situation ofxi’an, use the random stratified sampling method to test pipe material in18different levels ofqualification enterprise of fastener scaffold engineering, and gain a total of2340original datasfor statistical analysis in the field of random size of parking48mm×3.5mm and48.3mm×3.6mm, length6m and3m steel pipe wall thickness, outer diameter and initial bending.Using the modified Mrs Grubbs law to test and eliminate outliers, set up a random distribution ofthe initial defects and probability statistics function parameters. Based on the finite elementtheory, considering the semi-rigid nodes, with the help of ANSYS software, build finite elementmodels. On the basis of the measured initial defects, using consistent modal method, at differentload conditions (full uniformly distributed load, full asymmetric load), different fastenertightening torque (30N·m,40N·m,50N·m), different defects (specification limit3L/1000, themeasured L/220) as parameters, analyze the influence degree to structural ultimate bearingcapacity and obtain load-displacement curve of the feature points, it can provide theoretical basisfor the safe use of scaffolding.