火灾高温下热铸锚抗拔性能研究  

Study on bond behaviour of hot-cast anchors under fire at elevated temperature

作　　者：杜咏[1] 黄雷 李国强[2] 章欣 DU Yong;HUANG Lei;LI Guoqiang;ZHANG Xin(College of Civil Engineering,Nanjing Tech University,Nanjing 211816,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816 [2]同济大学土木工程防灾减灾国家重点实验室,上海200092

出　　处：《建筑结构学报》2023年第10期222-233,共12页Journal of Building Structures

基　　金：国家自然科学基金面上项目(51878348);土木工程防灾国家重点实验室开放基金项目(SLDRCE14-05)。

摘　　要：为研究热铸锚在火灾高温下的耐火极限及失效模式,开展了18个锚固预应力平行钢丝束、钢绞线及高钒索的热铸锚高温抗拔性能恒载升温试验和4个恒载恒温试验并进行了其数值传热分析。试验结果表明:高温下热铸锚钢索端滑移时程表现为线性增长、加速增长及滑移位移突变三个阶段;在发生钢索锚固端滑移位移突变前,锚固索拉力基本保持不变,且拉力突降滞后于滑移位移突变;当张拉力水平不超过0.3,热铸锚锚固破坏时锌铜合金填料达到熔点;随着张拉力水平及温度水平增长,锚头内的钢丝对锌铜合金填料有明显的裹挟现象,表明高温下填料对钢丝握裹具有较好延性。基于试验及数值传热分析结果,建议以高温下热铸锚锚固端滑移量超过索体名义直径的8.5%作为热铸锚高温失效判断准则,并提出了验算热铸锚高温承载力的临界温度法。In order to explore the fire resistance and failure mode of hot-cast anchors at a high temperature,18 heating tests were conducted on the bond behaviour of hot-cast anchors anchoring prestressed parallel strand,steel strands or anchoring Galfan-coated steel cables under a constant load,while four tests were conducted on such anchors under a constant load and a constant temperature.The test results indicate that the slip process of cable end of hot-cast anchors at a high temperature can be divided into three stages:linearly slipping,accelerated slipping and jump slipping stage.The tensile force basically remains constant before the sliding critical points and it takes longer heating time to achieve the critical tension force of hot-cast anchors than jump slipping points.When the tension ratio did not exceed 0.3,the zinc copper alloy filler melted when the hot-cast anchor was destroyed.With the increase of tension ratio and temperature,there was an obvious phenomenon that zinc copper alloy filler wrapped prestressed steel cable in the anchor,which indicates that the filler of hot-cast anchors displayed effective bond strength at a high temperature.Based on the test results and numerical heat transfer analysis,it is suggested that the sliding displacement of the anchor reaches 8.5%of the nominal diameter of the steel cable as the failure criterion of hot-cast anchor at a high temperature,and the critical temperature method is proposed for checking high-temperature bearing capacity of hot-cast anchors.

关 键 词：热铸锚 受火试验 数值传热分析 高温抗拔性能 失效模式 

分 类 号：TU394[建筑科学—结构工程] TU317.1