基于部分侧移单杆稳定理论的无支撑扣件式模板支架承载力研究

RESEARCH ON THE BEARING CAPACITY OF STEEL TUBULAR FORMWORK SUPPORT WITH COUPLER WITHOUT X-BRACING BASED ON THE PARTIALLY-SWAY SINGLE POST STABILITY THEORY

首先对12组不同搭设参数并考虑了初始缺陷的模板支架模型进行了非线性有限元分析,得到了相应的模板支架的承载力和失稳模态。在有限元分析结果基础上,提出了基于部分侧移单杆稳定理论的模板支架简化模型并给出了相应的简化计算公式,得到无支撑扣件式模板支架的理论承载力。其次,对上述12组不同搭设参数下的模板支架进行了原型试验,试验结果与有限元计算结果基本吻合。最后,对简化模型所得结果与试验和有限元结果进行了分析比较,结果表明该文所提出的无支撑扣件式模板支架的简化模型及相应的计算公式具有较高的计算精度,能够满足实际工程应用的要求,建议考虑将其应用在模板支架规范中。

In order to study the stability behavior of steel tubular formwork support with coupler without X-bracing systematically, the semi-rigid character of the couplers and different geometric parameters under idealized conditions are considered, and non-linear finite element models of twelve steel tubular formwork supports with coupler without X-bracing are established to analyze the critical loads and failure modes. According to the results of the finite element analysis and the partially-sway single post stability theory, a simplified model and corresponding formula are proposed to calculate the bearing capacity of this kind of formwork supports. The prototypes of twelve formwork supports are tested, and the stability behaviors and failure modes are derived. The test results correspond well with FEM analysis, and both of them showed that the typical failure mode of steel tubular formwork support with coupler without X-bracing is the whole sway instability in short axis because its whole flexural stiffness is weaker compared with the long axis. Through the comparison of all the results, it is concluded that the simplified model and simple formula has a considerable accuracy to forecast the critical load of steel tubular formwork supports without X-bracing under uniform load, which should be adopted in the design standard.