轮扣式模板支撑架稳定承载力试验研究及有限元分析

Experimental study and finite element analysis of stable bearing capacity of wheel-buckle formwork supporting frame

轮扣式模板支撑架是由带轮盘立杆、带直插头水平杆、可调底座和可调托撑等配件组成的临时支撑结构。为研究其失稳机理和破坏模式,开展了4个足尺支撑架静力破坏试验,分析了水平杆步距、剪刀撑(无剪刀撑、水平剪刀撑、水平-竖向剪刀撑)等参数对支撑架稳定承载力的影响,结果表明:不论是否设置竖向剪刀撑,支撑架破坏时均呈现顶部无侧移大波谷失稳破坏;水平杆步距由1.2 m降为0.9 m时,立杆稳定承载力增加了21.5%;水平剪刀撑和竖向剪刀撑的布置均可以提高立杆稳定承载力,且设置水平-竖向剪刀撑比未设置剪刀撑时,立杆稳定承载力提高了78.4%。总体上,各支撑架立杆稳定承载力试验值是采用JGJ 300—2013《建筑施工临时支撑结构技术规范》计算的承载力值的1.62~2.19倍,表明规范公式的计算结果具有足够承载力储备。采用有限元软件ABAQUS对足尺支撑架静力试验进行了模拟,有限元模拟结果与试验结果总体吻合较好,证明可以采用数值方法对轮扣式模板支撑架稳定承载性能进行预测。

The wheel-buckle formwork supporting frame is a temporary supporting structure composed of fittings such as uprights with wheel discs,horizontal rods with straight plugs,adjustable bases and adjustable braces.In order to study its instability mechanism and failure mode,four static failure tests of the supporting frames were carried out,and the influence of some parameters,such as step distance of horizontal rod,scissor brace(no scissor braces,horizontal scissor braces,horizontal and vertical scissor braces),on the stable bearing capacity was analyzed.The results show that,the four supporting frames show a non-sway buckling mode at the top with a large wave valley regardless of whether vertical scissor braces were installed or not.The stable bearing capacity of upright tube increases by 21.5%when the lift height reduces from 1.2 m to 0.9 m.The arrangement of horizontal and vertical scissor braces can improve the stable bearing capacity of the upright tube.Compared with the one with no scissor braces,the stable bearing capacity of the upright tube increases by 78.4%when the horizontal and vertical scissor braces are set simultaneously.In general,the test values of the stable bearing capacity of the upright tube are 1.62-2.19 times of the values calculated using the JGJ 300—2013‘Technical code for temporary support structures in construction’,which indicates that the JGJ 300—2013 code has sufficient safety for the bearing capacity.Numerical simulations of the tests using the ABAQUS software were conducted and the results showed good agreement with the test results,which proves that the finite element method can be used to investigate the bearing capacity of wheel-buckle formwork supporting frames.