钢筋混凝土梁-柱-板边节点抗剪强度计算模型

Analytical model for shear strength of reinforced concrete beam-column-slab exterior joints

根据钢筋混凝土梁-柱-板边节点的破坏特点,对软化拉压杆模型中框架节点有效宽度的计算方法进行修正,并考虑现浇板中配筋对斜压杆高度的影响,提出含正交梁的钢筋混凝土梁-柱-板边节点的修正软化拉压杆分析模型,并应用该模型对国内外11个框架边节点试件的受剪性能进行理论分析。研究结果表明:对于"等强"节点试件,修正软化拉压杆模型计算得到的框架节点受剪承载力与软化拉压杆模型计算结果相比和试验结果吻合更好,而现行规范建议设计方法计算值比试验值大,核心区存在安全隐患;对于"强节点"试件,修正软化拉压杆模型可以合理地预测梁-柱-板边节点的破坏模式,由该建议模型计算得到的框架节点受剪承载力比现行规范建议设计方法计算结果保守,可确保框架结构安全可靠。

According to the study on failure characteristics of reinforced concrete beam-column-slab exterior joints, a modified softened strut-and-tie model, which can be used to calculate the shear strength of frame joint with orthogonal beams, is put forward by taking the influence of the reinforcement in cast-in-place floor on the depth of the diagonal strut and making a modification on the effective width of the frame joints. Furthermore, the shear behavior of existing tested 11 reinforced concrete beam-column-slab exterior joints at home and abroad was analyzed by using the suggested model. The results indicate that the modified softened strut and tie model can more precisely predict the joint shear strength than that of softened strut-and-tie model for the ＂equal strong＂ joint specimens, but the joint shear strength predicted by the current code suggested method is larger than the test value, which may result in the joint core failure; For the ＂strong＂ joint specimens, the results also indicate that the failure mode of reinforced concrete beam-column-slab exterior joints predicted by modified softened strut and tie model is quite nearly with that of the test, and the joint shear strength predicted by the modified softened strut and tie model is more reasonable than that of the code method, which can make sure of the safety of reinforced concrete frame structure.