剪跨比不大于2.0的RC剪力墙力-位移全过程计算

为实现以剪切为主的（剪跨比不大于2.0）钢筋混凝土剪力墙力-位移全过程计算，在拉压杆模型基础上通过合理化假定提出了考虑变形协调的改进拉压杆模型.模型由对角斜向混凝土压杆、混凝土次斜压杆、混凝土次生斜压杆、水平拉杆、竖向拉杆及墙肢分布筋拉杆等组成，定量确定了模型中对角斜压杆及次斜压杆变形与墙端位移间的关系，建立了各杆件之间的变形协调条件、物理方程和平衡方程等计算式.此外应用该模型分析了轴压比，剪跨比及墙肢分布配筋率三种参数对剪力墙力-位移骨架曲线的影响.研究结果表明:与6片剪力墙试验结果对比，该模型能够较好地模拟剪跨比不大于2.0、以剪切受力特征为主的钢筋混凝土剪力墙力-位移骨架曲线；当轴压比由0.1依次增至0.5时，峰值承载力最大增量为27%；剪跨比由1.0依次增至2.0时，峰值承载力最大减少30%；分布配筋率由0.25%依次增至0.55%时，峰值承载力最大增量为6%；相比于其余两个参数，配筋率对墙肢承载能力的影响最小. 

Analysis of Entire Load-Deformation Process of Shear Span Ratio Not More Than 2.0: Reinforcement of Concrete Squat Walls by Strut-Tie Model

An improved strut-and-tie model that considers the deformation compatibility for determining the load-deformation relationship for squat walls (shear span ratio smaller than 2.0) is proposed. The model originates from the strut-and-tie model, and it includes a diagonal concrete strut, secondary concrete struts, subsidiary concrete struts, horizontal tie, vertical tie, and shear reinforcement ties. A definite equation between the deformation of two types of concrete struts (a diagonal concrete strut and four secondary concrete struts) and the displacement of the squat walls is given. The relationship among compatibility, equilibrium, and constitutive laws in each of the strut and ties was established. In addition, parameter analyses were conducted using the improved strut-and-tie model to study the effect of axial load, aspect ratio, and distribution reinforcement ratio on the skeleton curves of shear walls. The results show that, compared with the test results for six shear walls, the forces and deformations of the predicted members' are in reasonable agreement with test results. During parameter analysis, when the axial load ratio increases from 0.1 to 0.5, the maximum growth of load-carrying capacity is 27%. As the aspect ratio of shear walls increases from 1.0 to 2.0, the load-carrying capacity decreases 30%. As the distribution reinforcement ratio increases from 0.25% to 0.55%, the load-carrying capacity increases only 6%. The effect of the distribution reinforcement ratio on load-carrying capacity is not significant compared with the other two parameters.