锚栓屈服型可抬升柱脚节点抗震性能试验研究

Experimental study on seismic performance of anchor joint with bolt yield-type liftable column

为满足结构在震中安全且震后可修复使用的目的,设计了一种锚栓屈服型可抬升柱脚节点,该节点是一种半刚性节点,将柱脚锚栓的一部分作为节点的阻尼器,阻尼器为柱脚提供抗弯能力和可抬升能力,在地震时柱脚节点塑性变形主要集中在阻尼器上,震后通过更换阻尼器即可完成柱脚节点的修复。为此,设计一组普通外露式柱脚节点和锚栓屈服型可抬升柱脚节点进行对比试验,并通过拟静力试验,研究它们在低周往复荷载下的滞回特性、抗弯承载力、刚度退化、耗能能力等抗震性能,同时研究柱脚节点在更换阻尼器前后的抗震性能。研究结果表明:对比普通外露式柱脚节点,锚栓屈服型可抬升柱脚具有更好的耗能能力和变形能力,试件的损伤基本集中在可更换的阻尼器上,耗能模式和损伤机制较为合理。在进行修复后,除初期转动刚度略低于修复前试件外,整体抗震性能基本可恢复至震前水平。另外,该新型柱脚的阻尼器拆卸和更换较为简便。

In order to ensure the safety of the structure in the epicenter of the earthquake and the rapid repair and use after the earthquake,a liftable column base node with yield-type anchor bolts was designed.This node was a semi-rigid node.A part of the column base anchor bolts were used as the damper of the node.The damper provided the bending resistance and uplift capacity for the column base.The plastic deformation of the column base node was mainly concentrated on the damper during the earthquake.After the earthquake,the column base node could be repaired by replacing the damper.To this end,a set of ordinary exposed column base nodes and liftable column base nodes with anchor bolt yield-type were designed for comparative tests,and their seismic performance under low cycle repeated loads,such as hysteresis characteristics,bending bearing capacity,stiffness degradation,energy dissipation capacity,were studied through quasi-static tests.At the same time,the seismic performance of column base nodes before and after replacing dampers were also studied.The research results indicated that compared to ordinary exposed column base nodes,the yield-type anchor bolts could lift the column base node with better energy dissipation and deformation capacity.The damage of the specimens was mainly concentrated on replaceable dampers,and the energy dissipation mode and damage mechanism were more reasonable.After the repair,except for the initial rotational stiffness slightly lower than the pre repair specimen,the overall seismic performance could basically recover to the pre earthquake level.In addition,the damper of the new column base was easy to disassemble and replace.