基于修正拉-压杆模型的型钢混凝土深梁受剪承载力分析

在型钢混凝土深梁抗剪性能试验基础上，基于修正拉-压杆理论，考虑拉杆分力对受剪承载力的有利影响，采用型钢混凝土深梁的受压区高度作为上部节点高度，并对型钢翼缘和腹板进行合理简化，建立了型钢混凝土深梁的修正拉-压杆模型，推导了型钢混凝土深梁受剪承载力计算公式。将该文提出计算方法与ACI规范拉-压杆模型以及中国规范的计算方法进行比较可得：1）该文建立的修正拉-压杆模型，能较好反映型钢混凝土深梁的剪切传力机理和破坏模式，其受剪承载力计算值与试验结果吻合较好；2）采用JGJ 138-2001计算型钢混凝土深梁的受剪承载力偏低，离散性较大；按YB 9082-2006计算剪跨比大于2的构件受剪承载力偏于不安全。

ANALYSIS ON SHEAR CAPACITY OF SRC DEEP BEAMS BASED ON MODIFIED STRUT-AND-TIE MODEL

Based on the research of steel reinforced concrete (SRC) deep beam test and the modified strut-and-tie model (STM), a modified strut-and-tie model for SRC deep beams was established and the shear capacity design formula of SRC deep beams based on the model was deduced, which considers the favorable influences of the tie bar, taking the depth of compression zone of SRC deep beams as the depth of the top nodes and reasonably simplifying the steel flange and web. By comparing the test results and the calculation in this paper with the strut-and-tie models of ACI and Chinese code, the following conclusions can be drawn:1) force-transferring mechanism and failure mode can be reflected effectively, and the calculated values of shear capacity based on the modified strut-and-tie model for SRC deep beams presented in this paper agrees with the test result; 2) the shear capacity of SRC deep beams calculated by the JGJ 138-2001 shows high discreteness and low average value. The shear capacity of SRC deep beams with shear span ratios greater than 2 calculated by the YB 9082-2006 was not conservative.