FRP筋混凝土板冲切承载力计算方法

基于临界剪切裂缝理论，提出FRP筋混凝土板冲切承载力的计算方法. 该方法考虑拉伸刚化效应的混凝土拉伸应力-应变关系，利用截面分析法确定FRP筋受弯构件的弯矩-曲率关系. 根据混凝土板的变形假定、弯矩-曲率关系以及板的平衡方程，确定FRP筋混凝土板的需求曲线. 收集文献中试验数据对该计算方法进行验证，并将其与其他计算模型进行比较分析. 参数分析结果表明：随着混凝土强度与柱头尺寸的增加，FRP筋板承载力名义应力相应降低，混凝土板的延性呈现增长趋势；随着配筋率与厚度的增加，板冲切承载力的名义应力增大，配筋率与厚度的增加会导致板延性降低，因此在设计中应充分考虑板厚与配筋率对FRP筋混凝土板延性的影响.

Computational method of punching-shear capacity of concrete slabs reinforced with FRP bars

A punching-shear capacity model for concrete slabs reinforced with fiber-reinforced polymer (FRP) bars was proposed based on critical shear crack theory. The moment-curvature relationship of FRP concrete slabs was established by a sectional analysis method, in which the tensile stress-strain relationship of concrete was incorporated with the tension stiffening effect. The demanding curve of FRP concrete slabs was determined by a simplified deformation of concrete slabs, the moment-curvature relationship of FRP concrete slabs, and the equilibrium equations of slabs. The validity of the model was verified with experimental results collected from the literature. At the same time, the accuracy of existing punching-shear models of FRP concrete slabs was compared and evaluated. The parametric analysis results indicate that the nominal punching shear stress in slabs increases but the critical rotation angle of slabs decreases with the increase of FRP reinforcement ratio and effective depth. As the strength of concrete and the loading area increase, the nominal punching shear stress in slabs decreases but the critical rotation angle of slabs increases. The effect of slab thickness and reinforcing ratio on the durability of concrete slabs should be considered in the design of slabs.