钢筋混凝土框架夹心节点抗震性能试验研究

钢筋混凝土框架结构中通常柱混凝土强度高于梁的混凝土强度，当节点与梁用较低强度混凝土同时浇筑时，便形成钢筋混凝土框架夹心节点。通过11个钢筋混凝土框架夹心节点（包括平面中节点2个，平面端节点2个，改进型平面节点4个，空间中节点、空间端节点、空间角节点各1个）及3个用于对比分析的传统空间节点（空间中节点、空间端节点、空间角节点各1个）的拟静力试验，结合之前完成的7个平面夹心节点试验及6组平面夹心节点与传统节点的抗震性能对比，对钢筋混凝土框架夹心节点的抗震性能进行研究，包括开裂损伤过程、失效模式、位移延性、变形性能、受压承载力、受剪承载力、滞回耗能、梁筋粘结锚固性能等。研究表明：虽然核心区混凝土强度降低对试件抗震性能有一定不利影响，但通常不会改变框架节点的破坏模式，满足剪压比、轴压比、梁柱混凝土强度比、核心区配筋量条件下的夹心节点，其抗震性能大多可以满足结构设计的需求，或采取加插短筋、增设斜筋等加强措施后可以满足。

Pseudo-static test for reinforced concrete sandwich beam-column joints

In reinforced concrete structures with high-strength concrete column and lower strength concrete beam, the beam-column joints with lower strength concrete are typically practiced. Such beam-column joints are named as sandwich joints and studied in this paper. Eleven specimens of sandwich joints (including of 2 plane interior joints, 2 plane exterior joints, 4 plane interior joints with strengthen measures, and 3 space joints) were tested under pseudo-statically to investigate the difference of seismic performance between 3 space sandwich joints and similar traditional joints. Combined the experimental results of 7 plane inferior joints and 6 group of comparative joints that studied before, integrated results and behaviors were studied including process of damage, failure mode, ductility, compressive resistant capacity, shear resistant capacity, energy dissipation capacity, beam bar anchorage capacity, joints shearing deformation and so on. Although the reduction of joint concrete strength had a certain negative impact on the seismic performance of the beam-column joints, failure mode was normally the same. If the factors of sandwich joints that consisting of shear-compression ratio, axial compression ratio, ratio of beam concrete strength to column strength, transverse reinforcement in the joint are limited, these joints would achieve sufficient performance for seismic prevention of structures. In order to achieve sufficient performance, strengthen measures such as adding vertical dowels and diagonal bars may be needed for few sandwich joints.