内置型钢连接件的预应力钢筋混凝土叠合梁受弯性能试验研究

Experimental study on flexural behavior of prestressed reinforced concrete beams with built-in steel connectors

本文提出了一种内置型钢连接件的预应力钢筋混凝土叠合梁,即在梁受拉区配置少量型钢作为装配式构件的连接件使用,同时在预制阶段对预制U型外壳施加预应力。为了研究该种新型预应力钢筋混凝土叠合梁受弯性能,共设计了4根预应力钢筋混凝土叠合梁和1根钢筋混凝土叠合梁,以预应力度、预应力筋布置形式(直线型、抛物线型)以及预应力施加顺序(整体浇筑前后)为研究参数进行试验研究。试验结果表明:在预制阶段施加预应力效果基本等同对整梁施加效果。施加预应力后,钢筋混凝土叠合梁的开裂荷载提高了3~4倍,预应力筋的布置形式主要影响叠合梁的开裂荷载,试验梁控制截面均满足平截面假定。基于试验结果,提出新型预应力钢筋混凝土叠合梁正截面受弯承载力计算式,其计算结果与试验结果吻合较好。

A prestressed reinforced concrete composite beam with built-in steel connectors is proposed, and a small amount of steel in the tension zone is used as the connectors of the fabricated components, and the prestressed U-shaped shell is prestressed in the prefabrication stage. In order to study the bending performance of this new type of prestressed reinforced concrete composite beams, a total of 4 prestressed reinforced concrete composite beams and 1 reinforced concrete composite beam are designed. Prestress degree, the prestressed tendon arrangement type(linear type, parabolic type) and the prestressing sequence(before and after the overall beams) are the research parameters for experimental research. The test results show that the effect of applying prestress in the prefabrication stage is basically the same as applying the effect to the entire beam. After the prestress is applied, the cracking load of the reinforced concrete composite beam is increased by 3 to 4 times. The layout of the prestressed tendons mainly affects the cracking load of the composite beam, and the control section of the test beam meets the assumption of flat section. Based on the test results, a calculation formula for the flexural bearing capacity of the normal section of a new type of prestressed reinforced concrete composite beam is proposed, and the calculation results are in good agreement with the test results.