基于转动角软化桁架模型的FRP连续螺旋箍筋混凝土梁的非线性分析

Non-linear analysis of concrete beams reinforced with continuous FRP rectangular spirals using rotating-angle softened truss model

为分析配置纤维增强复合(fiber reinforced plastics/polymers,简称FRP)连续螺旋箍筋的混凝土梁的受剪机理,采用混凝土开裂后的主压应力轴与水平轴之间的夹角(转动角)为裂缝开展角,建立了受剪单元的力学模型,据此建立了试件的转动角软化桁架模型,包括应力平衡方程、应变协调方程以及混凝土软化双轴本构关系等材料本构关系。在此基础上,采用迭代和逐次逼近的数值分析方法,对试件进行了受剪非线性全过程分析。采用建议的模型,对FRP连续螺旋箍筋混凝土梁的抗剪承载力和抗剪破坏模式进行了预测,所得结果与试验结果较为吻合。

The rotating-angle softened truss model of membrane elements was referred in the shear mechanism analysis of concrete beams reinforced with continuous fiber reinforced plastics(FRP)rectangular spirals.The mechanical model of the shear elements was founded,which assumed that the rotating-angle coincide with the actual crack angle(the angle between the principal compressive stress axis and the horizontal axis after concrete cracking).The stress equilibrium equation,the strain compatibility equation,and constitutive laws of materials including the softened biaxial constitutive law of concrete were summarized,which represented the basic equations of the rotatingangle softened truss model of the test pieces.The non-linear analysis of the shear behavior was carried out based on these equations using the arithmetic of iteration and step approximation.The rotating-angle softened truss model proposed in this paper was used in the predictions of the shear capacity and shear failure modes of concrete beams reinforced with continuous FRP rectangular spirals,and the theoretical results correlated well with test results.