Development of New-Generation Seismic Design Method for Pile Cap Joints based on Performance Evaluation

承台是连接柱、桩、基础梁的重要构件。桩帽中的竖向构件有柱和桩两种。为此，进行了单桩、柱、基础梁和承台组合体的水平荷载反复试验，并考虑了承台的抗震性能。对于一般的钢筋混凝土梁柱节点，其斜向抗剪开裂强度和极限抗剪强度可采用柱、桩和承台截面或柱和承台截面的平均值作为竖向构件截面的预估值。但在本研究中，采用了小直径桩，这是小于柱截面的情况下，低的建筑物。通过设置抗剪钢筋，提高了极限抗剪强度。

The pile cap is a very important member connecting the column, pile, foundation beams. There are two kinds of vertical members, columns and pile, in a pile cap. So, the seismic behavior of pile cap is more complicated than the beam column joint.We performed lateral load reversal tested of subassemblages with one pile, column, foundation beam and pile-cap, and considered the earthquake resistant performance of pile cap. The diagonal shear crack strength and ultimate shear strength can be estimated by the prediction method for usual RC beam-column joints to apply the vertical member section to the average between the pile, the column and the pile cap section or that between column and pile cap. But in this research, the small diameter pile was applied, which was smaller than the column section in case of the low buildings. The ultimate shear strength was increased by mounting the shear reinforcements.