摘要
钢绞线锚固系统具有很强的受火敏感性,其火灾下的受力性能不容忽视。以我国工程中广泛使用的1 860 MPa级钢绞线夹片锚为研究对象,采用足尺试件对其抗火性能进行研究,分析不同应力水平(0.3、0.4)对锚固系统耐火极限和临界温度的影响规律。试验结果表明:火灾下钢绞线夹片锚的破坏模式为钢绞线滑移,并伴有断丝现象发生;高温下钢绞线在夹片锚内的滑移大致包括平稳持载和滑移急剧增长2个阶段;当应力水平从0.3增加到0.4时,锚固系统的破坏时间分别为74 min和69 min,对应的临界温度相近,约为520℃;总体而言,随着应力水平的增加,钢绞线锚固系统破坏时间变短,升温速率增大,耐火性能下降。
Because the anchorage system for steel strand has a strong sensitivity to fire hazard,the resistance capacity under fire should be considered seriously.The fire resistance capacity of wedge-type anchorage of 1 860 MPa steel strand,which is widely applied in engineering projects in China,is studied using the full-scale specimens in this paper,in order to investigate the duration time and critical temperature under axial tension loading and fire.The test parameters are set differently based on stress levels,which are designated as 0.3 and 0.4.Test results show the failure mode of wedge-type anchorage system at high temperature is through slippage of steel strand from anchorage,and some rupture of certain steel strand is also observed.The process of slippage under fire heating can be divided into two stages:stable growth and failure.The failure time is 74 minutes and 69 minutes respectively according to different stress levels,as the critical temperature for the anchorage system is quite close(around 520 ℃).In summary,the fire resistant ability of wedge-type anchorage system decreases as the stress level is raised,while the failure time decreases and the heating rate increases.
作者
崔启
朱美春
张海良
何旭初
CUI Qi;ZHU Meichun;ZHANG Hailiang;HE Xuchu(College of Civil Engineering,Tongji University,Shanghai 200092,China;College of Civil Engineering,Shanghai Normal University,Shanghai 201418,China;Shanghai Pujiang Cable Co.,Ltd,Shanghai 200331,China)
出处
《建筑钢结构进展》
CSCD
北大核心
2019年第6期107-113,共7页
Progress in Steel Building Structures
基金
上海市自然科学基金(18ZR1427900)
关键词
钢绞线
锚固系统
大空间火灾
破坏模式
临界温度
steel strand
anchorage system
large-space fire
failure mode
critical temperature
作者简介
崔启(1986—),男,硕士研究生,主要从事建筑结构抗火方面的研究。E-mail:jacob@tongji.edu.cn;通信作者:朱美春(1979—),女,博士,副教授,主要从事钢结构抗火方面的研究。E-mail:zhumeichun@shnu.edu.cn。
