【摘要】 应用软化拉压杆模型对钢筋混凝土框架节点核心区进行受剪承载力计算时,常常基于经验取柱截面宽度作为节点的有效宽度参与抗剪强度计算。但是,对于实际工程中含有现浇楼板的框架中节点,节点的有效宽度在核心区上下验算截面并不相同且随着作用外力的增加而逐步增大,直至软化拉压杆模型中结点域(nodal zone)混凝土达到其抗压强度后压溃而失效。本文对软化拉压杆模型中节点有效宽度的计算方法进行了改进,应用修正软化拉压杆模型(Modified Softened Strut-and-Tie,简称MSST)对国内外63个框架中节点试件的抗剪强度进行理论计算,并将受剪分析得到的峰值剪应力计算结果与现行规范建议方法及软化拉压杆模型方法的计算结果进行对比。结果表明: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,与现行规范建议设计方法计算结果相当,该建议模型可较为合理地反映含现浇楼板框架节点的受力机理。更多还原

【Abstract】 For the shear analysis of interior joints of a reinforced concrete structure by using a Softened Strut-and-Tie model,the effective joint width can always be taken as the whole column width empirically.However,for the frame joint with a cast-in situ slab,the effective joint width is not equal to each other at the top and bottom of a beam column interface.Additionally,the effective joint width also gets wider with the increasing compression stress and ends at the location of crushing.A Modified Softened Strut-and-Tie(MSST) model suggested a more rational calculation method for effective joint width.The shear strength of existing tested 63 interior joints was calculated by Using the Modified Softened Strut-and-Tie model.Furthermore,the theory results were compared with those of the Softened Strut-and-Tie model and those of the code method.The results indicated that the Modified Softened Strut-and-Tie can more precisely predict the joint shear strength than that of the Softened Strut-and-Tie model;Furthermore,the results also indicated that the shear strength of joint core calculated by an MSST model is quite nearly with that of the code method.Thus,the MSST model can reasonable reveal the failure mechanism of beam-column-slab joints.更多还原