Design of Reinforced Concrete External Beam to Column Joints Subjected to Earthquake Loading

本文旨在为钢筋混凝土双向框架结构外梁柱节点的抗震设计提供参考。对具有单向或双向梁的裸梁-柱组合和双向框架的板-梁-柱组合进行了试验。根据试验结果，得出如下结论：在外节理中，节理剪切主要通过对角压杆机构而不是桁架机构传递。因此，水平缝箍对混凝土支柱的围合是有效的。底部梁杆向下弯曲，日本实践的标准细节，加速了节点抗剪能力和刚度的恶化。柱轴力提高节理抗裂能力和抗剪刚度劣化率。虽然卸载横向梁对改善主梁方向的性能是有效的，但在横向梁偏移到塑性变形范围后，这种效果明显消失。板-梁-柱组合的双向同时加载比单向交替加载更能提高结构的耗能能力。在试验结果的基础上，提出了外部梁柱节点的抗震设计方法。

The aim of the project is to provide a proposal for seismic design of external beam-column joints in reinforced concrete two-way framed structures. Tests were performed on bare beam-column assemblages having one-way or two-way beams and slab-beam-column assemblages of two-way frames.From the test results, following remarks were derived;1. In external joints, joint shear is transferred mainly by the diagonal compression strut mechanism rather than the truss mechanism. Therefore, horizontal joint hoops are effective to confining concrete struts.2. Downward bending of bottom beam bars, the standard details of Japanese practice, accelerates the deterioration of joint shear capacity and rigidity.3. Column axial force improves joint crack capacity and deterioration rate of shear rigidity.4. Though the unloaded transverse beams are effective to improve the behavior in the direction of the main beam, this effect is cleary lost after the excursion of transverse beams into the plastic deformation range. Simultaneous bi-direction loading of slab-beam-column assemblages increases the energy dissipation capacity in comparison with alternative uni-directional loading.5. Based on the test results, a seismic design method for external beam-column joints was proposed.