Shear Design Method for Reinforced Concrete Interior Beam-Column Connections

这是为期三年的研究项目的最后一年，编写了一份研究报告。主要研究成果总结如下：1.梁柱节点的抗剪通常被认为是由桁架机制和支撑机制共同作用的，但桁架机制是不可靠的，因为梁屈服后节点内部的粘结抗力很难保持；2.在梁柱节点中放置横向钢筋对节点的抗剪能力没有贡献，但在剪切开裂后对节点起到了有效的约束作用；3.横梁即使在正交地震荷载作用下弯曲屈服后，也能有效地提高节点的抗剪能力；4.板也能有效地提高节点的抗剪能力。从上述研究结果来看，建议的设计准则是防止层间位移角0.02或梁延性系数4.0以下的节点发生剪切破坏；即：1.节点剪应力应控制在混凝土抗压强度的0.25倍以下；2.如果将横梁连接到节点上，剪应力水平的限制可放宽至混凝土强度的0.33倍。

This is the final year of three-year research project, a research report was prepared. Major research findings are summarized below :1. Shear in a beam-column connection is normally considered to be resisted by truss mechanism and strut mechanism, but the truss mechanism is not reliable because the bond resistance is difficult to maintain within the connection after beam yielding,2. The lateral reinforcement placed in the beam-column connection does not contribute to the shear resistance, but is effective confining the connection after shear cracking,3. The transverse beams, even after flexural yielding under orthogonal earthquake loading, are effective in increasing shear resistance of the connection,4. Slab was also found effective in increasing shear resistance of the connection.From the above research findings, design criteria are proposed to prevent shear failure within the connection up to a story drift angle of 0.02 or to a beam ductility factor of 4.0 ; i. e.,1. The shear stress in the connection should be kept below 0.25 times the concrete compressive strength,2. If transverse beams are connected to the connection, the limit on shear stress level may be relieved to 0.33 times the concrete strength.