Analysis About The Bearing Capacity Of Fastener Steel Tube Full Hall Formwork Support Based On Initial Defects

With the continuous development of China's economy and society,the construction industry has also flourished.The fastener steel tube full hall formwork support,which plays a supporting role in the construction process,has made the application more widely due to the wide range of sources of raw materials,convenient disassembly and assembly,and relatively low prices.However,the steel formwork support often affects the stable bearing of the entire frame due to some defects before supporting the construction load.We call these defects initial defects.This article mainly studies the initial defects in three aspects of configuration factors(lift height,longitudinal and transverse spacing of upright tube,setting of diagonal bracing,setting of bottom reinforcing tube),material factors(Steel pipe section size,initial bending of steel pipe,tightening torque of coupler),and environmental factors(differential settlement of foundation,wind load).Obtained the specific effect of initial defects on the bearing capacity of fastener steel tube full hall formwork support,which provides the theoretical basis and reference significance for the erection of the steel pipe support frame in the actual construction process.In this paper,through theoretical analysis and using finite element software ANSYS simulation analysis,some conclusions about the influence of initial defects on the bearing capacity of fastener steel tube full hall formwork support are obtained.The main results are as follows:1.Configuration factors: The bearing capacity of the fastener steel tube full hall formwork support decreases with the increase of the lift height.The bearing capacity of the frame body also decreases with the increase of the longitudinal and transverse spacing of upright tube,and the influence of longitudinal transverse spacing of upright tube is greater,so it needs attention.The arrangement of diagonal bracing has a more prominent effect on the bearing capacity of fastener steel tube full hall formwork support,and the bearing capacity increases with the increase in the arrangement density of diagonal bracing.And considering safety and economy,it is recommended that horizontal diagonal bracing should be set every 3 steps,and vertical diagonal bracing should be set every 3rows.Lastly the setting of bottom reinforcing tube is very important for bearing capacity of fastener steel tube full hall formwork support.It is recommended that the floor height of bottom reinforcing tube should be set to 0.2m.2.Material factors: The ultimate load-carrying capacity of fastener steel tube full hall formwork support decreases as the outer diameter and wall thickness of the steel pipe decrease.As the initial bending of the steel tube becomes larger,the bearing capacity of the entire frame is greatly reduced under the ideal condition.As the tightening torque of coupler increases,the bearing capacity of the steel formwork support gradually increases.The tightening torque of coupler is recommended to be set between 40N·m and50N·m.3.Environmental factors: The uneven settlement of the foundation will greatly reduce the bearing capacity of the fastener steel tube full hall formwork support,and the more the subsidence site,the faster the bearing capacity declines.The continuous increase of wind load will cause the bearing capacity of the steel formwork support to decrease continuously,and when the equivalent nodal wind load is 3k N,it is an inflection point.More than this turning point,the descent speed of bearing capacity has increased.