基于有侧移半刚性连接框架理论的无支撑模板支架稳定承载力分析及试验研究

Experimental and theoretical research on capacity of unbraced steel tubular formwork support based on sway frame with semi-rigid connection theory

在考虑节点半刚性性质的基础上,利用有侧移三层柱的框架模型推导有侧移半刚性连接钢框架中柱的计算长度系数方程,并将这一方法引入无支撑扣件式模板支架稳定承载力计算中,将模板支架的整体稳定简化成立杆的稳定,进而得到无支撑扣件式模板支架的理论稳定承载力。利用ANSYS软件,考虑直角扣件的半刚性性质,建立了6组不同搭设情况下无支撑扣件式模板支架的有限元模型,对其稳定承载力及失稳情况进行分析。对照有限元模型的搭设情况,对模板支架进行试验研究,得到相应的稳定承载力,试验结果与有限元结果基本吻合。将理论计算结果与试验及有限元分析结果进行对比可知,在其他搭设参数相同的情况下,模板支架的整体稳定承载力随步距、立杆间距的减少而提高,而且理论计算结果更加偏于安全,进一步说明有侧移半刚性连接框架理论在无支撑扣件式模板支架稳定承载力计算中的可行性及适用性,并可以考虑将此理论应用到规范中,为今后对扣件式模板支架稳定承载力的进一步分析及研究提供理论参考。

Based on the three-column subassemblage model,the governing equations for determining the effective length factor of columns in sway frames were derived considering the semi-rigid character of beam-to-column connections.Through transforming stability analysis of the formwork support into that of single post,the bracing capacity of steel tubular formwork support without X-bracing was calculated using the theory of sway frame with semi-rigid connection.Advanced non-linear finite element models of six steel tubular formwork supports with different geometric parameters were established considering the semi-rigid character of the couplers to evaluate the critical loads and failure modes under idealized conditions in ANSYS.Six steel tubular formwork supports were built and tested to failure in order to examine their stability behavior and failure modes.The FEM results were well consistent with those of the test.Compared with the results of tests and FEM,the theoretical results have the same changing rulers with the tests and FEM,and more conservative.It can conclude that the sway frame with semi-rigid connection theory presented in this paper has feasibility and applicability in forecasting the critical load of unbraced steel tubular formwork support with coupler under uniform load,and it is considerable to apply this theory in code（Technical code for safety of steel tubular scaffold with couplers）.The results obtained in this paper can be a significant reference for later research and design.