Innovative detailing for shear in concrete using high performance materials

现有的钢筋混凝土剪切设计模型使用基于应力的构件强度组合方法，从混凝土贡献和基于桁架类比的剪切钢筋贡献来计算构件强度。这些模型限制了设计中允许的抗剪钢筋的最大强度，以便限制失效时的裂缝宽度。剪力筋的最大间距由经验规则根据内部桁架的假设角度来确定。自20世纪60年代以来，有限的研究表明，当这些标准中的任何一个放松时，安全设计是可能的。改进的剪切能力模型，直接考虑剪切钢筋应变和间距，将允许经济和安全的使用现代，耐用的钢筋材料作为箍筋。

Existing shear design models for reinforced concrete use a stress-based compositional approach to member strength, from both a concrete contribution and from a shear reinforcement contribution based on a truss analogy. These models limit the maximum strength of the shear reinforcement permitted in design, in order to limit crack widths at failure. Maximum spacing of the shear reinforcement is defined by empirical rules based on an assumed angle for the internal truss. Limited studies since the 1960's have shown that safe designs are possible when either of these criteria are relaxed. Improved capacity models for shear that directly consider both the shear reinforcement strains and spacing, will permit economical and safe use of modern, durable reinforcement materials as stirrups.