设置镦锚钢筋的地下综合管廊墙板节点的抗震性能

Seismic performance of utility tunnel wall-slab joints with anchorage button-head reinforcement

为研究使用镦头锚固钢筋的地下综合管廊墙板节点的抗震性能,对6个足尺墙板节点进行了低周往复荷载试验,考察了地下综合管廊墙板节点的承载能力、失效模式、滞回耗能能力、位移延性等抗震性能指标,将现浇墙板节点试件与叠合装配式墙板节点试件的试验结果进行对比,分析了镦锚钢筋锚固长度的合理取值,采用有限元程序建立节点的精细有限元模型,验证了其正确性。结果表明:设置镦头钢筋锚固的叠合装配式节点具有与现浇节点大致相当的承载能力,位移延性及耗能能力相对较好,叠合装配式节点能达到与现浇节点相近的抗震性能要求。镦头钢筋锚固长度采用0.5labE时,地下综合管廊墙板节点试件抗震性能满足抗震设计要求,随着镦锚钢筋锚固长度的减小,墙板节点的承载能力和变形能力逐渐下降,延性及耗能能力逐渐降低;叠合装配式节点在低周往复加载下,预制叠合面缝隙开展较大,节点核心区混凝土易发生破坏,在实际工程中需采取必要的加强措施,加强节点区连接构造措施。

To evaluate the seismic performance of utility tunnel wall-slab joints using anchorage button-head reinforcement,pseudo-static tests were carried out on six full-scale wall-slab joint specimens.Bearing capacity,failure mode,hysteretic energy dissipation,displacement ductility and other seismic performance indexes of utility tunnel wall-slab joints were investigated.Comparing the test results of the cast-in-place wall-slab joint specimens with that of composite fabricated wall-slab joint specimens,reasonable anchorage length of upsetting steel bar was determined.The finite element model of these wall-slab joints was established and its validity was checked.The results show that the composite fabricated wall-slab joint using anchorage button-head reinforcement has the same bearing capacity as that of the cast-in-place joint,and displacement ductility and energy dissipation capacity are good,indicating that the composite fabricated wall-slab joints can meet the seismic performance requirements.When the anchorage length of upsetting steel bar is longer than 0.5labE,the seismic performance of joint specimens can meet seismic design requirements.However,as the anchorage length of upsetting steel bar decreases,the bearing capacity and deformation capacity of wall-slab joints gradually decrease,and the ductility and energy dissipation capacity also decrease gradually.The crack propagation at the composite surface of prefabricated wall-slab joints is greater,and damage in the core area of the joint is severe.Consequently,necessary reinforcement measures need to be taken and the connection measures of the joint area need to be strengthened in engineering practice.