开口截面钢-混凝土组合梁弯扭性能非线性分析

Nonlinear analysis of composite steel-concrete beams with open sections under combined bending and torsion

在钢筋混凝土变角软化桁架模型的基础上,提出了适于分析开口截面钢-混凝土组合梁弯扭性能的三维桁架模型。在弯扭作用下,组合梁截面各单元分别处于一维应力状态(体系1)和二维应力状态(体系2),体系1用来抵抗由弯矩和扭矩引起的截面纵向应力,体系2用来抵抗由扭矩引起的截面剪应力,两者通过截面的纵向应变协调和内力平衡条件联系起来。分析充分满足平衡条件、变形协调条件和材料本构方程。通过对部分试件的计算验证,结果表明该模型不仅可以用于预测组合梁的极限强度,而且为混凝土翼板开裂后组合梁全过程分析,提供了有效途径。

Based on the rotating-angle softened truss model theory, a three-dimensional truss model is presented for the analysis of composite steel-concrete beams with open sections under combined bending and torsion. In this model, each element of the section is subjected to two systems of stresses separately. A one-dimensional stress system resists the longitudinal stresses due to bending and torsion, and a two-dimensional stress system resists the shear stresses due to torsion. The two stress systems are combined through the compatibility of strains and the equilibrium of stresses in the longitudinal direction. The equilibrium equations, compatibility equations and the constitutive laws of materials are satisfied. Through the analysis of Several available examples, this model can predict not only the ultimate strength of the composite member, but also provide a tool to obtain the entire load-deformation history after the cracking of the concrete flange.