固角软化桁架模型在RC框架变梁中节点受剪分析的应用研究

Shear behavior analysis of reinforced concrete interior joint with different depth beams using fixed angle softened truss model theory

固角软化桁架模型是在转角桁架模型基础上发展起来的一种新模型,主要适用于软化桁架模型中旋转角α在45°±12°范围之外变化的结构混凝土的受剪分析。该文在以往试验研究基础上,建立考虑左右梁高不等特性的中节点等效核心区在剪、压复合作用下的计算模型,应用固角软化桁架模型对10个钢筋混凝土变梁中节点试件进行受剪分析。结果表明:基于固角软化桁架模型计算得到的节点剪应力-剪切变形曲线与试验结果吻合较好,与现行规范给出的半经验半理论的受剪承载力计算公式相比,固角软化桁架模型有明确的力学计算模型,可为钢筋混凝土框架节点的受剪设计提供参考。

The fixed angle softened truss model is a new method originated from the rotating angle softened truss model.This new model can be employed for analyzing and determining the shear strength of reinforced concrete with rotating angle α beyond the range between 33° and 57°.Based on existing study,an analytical model for an equivalent joint core of frame joint under the combined action of axial load and shear is established,and the shear stress versus shear angle curves of the equivalent joint core of 10 tested specimens were calculated by using fixed angle softened truss model.Results indicated that the shear behavior of equivalent joint core calculated by fixed angle softened truss model agree quite well with test results.Comparing the semi-empirical formulas of joint shear strength suggested by the current codes,the fixed angle softened truss model has a more clearly definited mechanical model and can serve for the shear design of frame joint of reinforced concrete structures.