Innovative detailing for shear in concrete using high performance materials

现有的钢筋混凝土抗剪设计模型采用基于应力的组合方法来计算构件强度，既有混凝土贡献，也有基于桁架类比的抗剪钢筋贡献。这些模型限制了设计中允许的抗剪钢筋的最大强度，以限制破坏时的裂缝宽度。剪力筋的最大间距由基于内部桁架的假定角度的经验规则定义。自20世纪60年代以来的有限研究表明，S已经表明，当这两个标准中的任何一个放松时，安全设计都是可能的。改进的剪切能力模型直接考虑了剪切钢筋应变和间距，将允许经济和安全地使用现代、耐用的加固材料作为箍筋。

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.