拉拔荷载下膨胀锚栓连接件研究

Research on Expansion Anchor Bolt Connectors under Pull-out Load

随着基础建设钢混组合结构发展,各种锚栓连接件得到广泛应用。为深化对锚栓连接件的认识,介绍不同锚栓种类及其特点,并着重分析膨胀锚栓连接件在拉拔荷载下的破坏模式、受力机理及极限抗拉承载力预测模型,为今后膨胀锚栓连接件的设计、研究及应用提供参考。分析结果表明:因膨胀锚栓在施工中具有方便性和可调整性,后锚固锚栓相比现浇锚栓在实际工程中应用较多;膨胀锚栓和混凝土间通过摩擦力及机械咬合力起锚固作用,且由膨胀力引起的摩擦力起主要作用;膨胀锚栓连接件在拉拔荷载下呈现椎体、拔出、穿出、钢材破坏4种典型破坏模式;钢材、穿出破坏的延性显著大于椎体、拔出破坏;锚栓有效埋深是影响锚栓连接件破坏模式和极限抗拉承载力的主要因素,且随着埋深的增大极限抗拉承载力呈上升趋势。

Various anchor bolt connectors have been widely used due to the development of their combined structures in recent years. In order to have an in-depth understanding of anchor bolt connectors, this paper introduces different types and characteristics of anchor bolts, and emphatically analyzes the failure mode, stress mechanism and ultimate bearing capacity prediction model of expansion anchor bolts under pull-out load, so as to support the design, research and application of expansion anchor bolts in the future. The results of the study show that: Due to their convenience and adjustability in construction, post-installed anchor bolts are more applied in construction than cast-in-situ anchor bolts;expansion anchor bolts and concrete are anchored by friction and mechanical engagement force, and the friction caused by expansion force plays a major role;expansion anchor bolts present four typical failure modes under pull-out load: cone failure, pullout failure, pull-through failure and steel failure;the ductility of steel failure and pullthrough failure is significantly greater than that of cone failure and pull-out failure;the effective burial depth of anchor bolts is the main factor affecting the failure mode of connectors and the ultimate pull-out bearing capacity, and the ultimate bearing capacity increases with the increase of burial depth.