可拆式钢筋桁架模板截面力学性能试验和计算方法

Experimental analysis of cross-section mechanical properties and calculation methods of detachable formwork with steel bar trusses

通过对全尺寸可拆式钢筋桁架模板在施工阶段的截面力学性能试验,研究了其在单调荷载作用下的破坏形态以及受力机理。并分别采用荷载-挠度曲线法和极限弯矩法计算了截面特性。分析表明:施工阶段可以采用上下弦连续的桁架计算模型,荷载-挠度曲线法计算结果与理论值偏差较大,其原因是:试件破坏过程由变形控制,而非强度,以及由于连接件与钢筋的相对滑移产生的附加挠度,极限弯矩法计算值与理论值较为吻合。在此基础上,给出了简支或等跨连续(两跨)梁计算模型的最大无支撑长度的建议值。

The cross-section mechanical properties of full-size detachable formwork with steel bar trusses were tested under construction stage and the failure mode as well as the mechanical behavior were analyzed under monotonic load,and the cross-section properties were calculated using load-deflection curve method and ultimate moment method.The analysis results showed that truss model with its chords to be continuous and webs can be used during construction,the error was much large between results of loaddeflection curve method and theoretical values,and the reason was that the specimen in failed procress is controlled by deformation,rather than the strength;and the additional deflection was generated by the relative slip between connector and reinforcement;and ultimate moment method were in good agreement with theoretical values.On the base of results,the suggestions were given that the biggest unsupported length under simply supported or continuous beam model.