摘要
高强度螺栓连接是钢结构现场安装的主要手段之一,高强度螺栓连接螺栓孔采用槽孔时对加工和安装误差适应能力更强,便于施工。目前对高强度螺栓槽孔节点的研究较少,对高温下高强度螺栓槽孔节点的研究更是空白。为此进行了14个高强度螺栓标准孔和槽孔连接节点在常温、130℃高温和200℃高温下滑移性能的试验研究,考虑了温度、孔型、螺栓直径等参数的影响,并利用高温应变计测量了高温下高强度螺栓预拉力。结果表明:1)在20~130℃期间,温度对标准孔试件滑移荷载和滑移变形有影响,抗滑移荷载减少0.9%~4.3%;抗滑移系数降低7.5%~7.8%;螺栓预拉力松弛约22.4%。2)在130~200℃期间,槽孔试件滑移荷载和滑移变形变化较明显。相对于常温情况,130℃和200℃下M30螺栓滑移荷载分别减少9%和34%,抗滑移系数分别降低11%和7%;螺栓预拉力出现不规则变化。3)常温条件下,相对于标准孔,槽孔的滑移荷载和抗滑移系数要小,且对于直径较大的螺栓,槽孔的削弱较小。M20和M30螺栓槽孔滑移荷载分别比标准孔的低11.0%和4.0%,抗滑移系数分别比标准孔的低12.0%和10.0%。4)130℃温度下,相对于标准孔,M30槽孔的滑移荷载和抗滑移系数分别降低9.0%和13.0%,且对比常温条件,130℃温度下槽孔的削弱更大。5)槽孔会加大螺栓预拉力松弛,130℃温度下,M30标准孔节点螺栓预拉力松弛约-16.3%;而槽孔节点螺栓预拉力松弛约-30.7%,比标准孔高14.4%。6)在20~130℃期间,M30螺栓的抗滑移系数比M20螺栓的大约30.0%,说明连接刚度越大,标准试件抗滑移系数值越大;200℃温度下,M30螺栓的抗滑移系数比M20螺栓的反而小12.4%,表明M20抗滑移系数出现异常。7)130℃时,M20和M30螺栓预拉力松弛分别约28.4%和16.3%,说明连接刚度越大,螺栓预拉力松弛越小;随着温度提高至200℃时,M20预拉力呈明显下降趋势,下降幅度比130℃时要大,离散性也大,M30螺栓预拉力呈现有升有降的状况,没有明显的规律性。
High strength bolt connection is one of major method used in steel structure construction on site.Taking the form of slotted hole in bolt connection,it will be more convenient and efficient in construction since this form shows better tolerance in installation deviation.At present,there is less research focused on high strength slotted bolt connection while it is blank in the research field of high strength slotted bolt connection under high temperature.14 tests were conducted according to different experiment schemes including standard or slotted hole high strength bolt connection and different test temperatures of room temperature,130℃and 200℃.Among these 14 tests,slippage in bolt connection was studied and variables including temperature,bolt hole style,bolt diameter and so on were considered.The high temperature strain gauge was adopted to observe the change of bolt pre-tension force throughout the tests.The results indicated that:1)From 20℃to 130℃,effects of temperature on slipping load and displacement were measured.Reductions were observed while temperature rising to 130℃and it showed 0.9%~4.3%reduction in anti-slip load,7.5%~7.8%reduction in mean slip coefficient and 22.4%reduction in bolt pre-tension.2)From 130℃to 200℃,effects of temperature were significant.Comparing to room temperature,reduction about anti-slip load of M30 bolt was 9%and 34%respectively for 130℃and 200℃while reduction about mean slip coefficient was 11%and 7%respectively.Irregular change of bolt pre-tension was observed under this temperature situation.3)Under room temperature,anti-slip load and mean slip coefficient were decreased in slotted hole bolt connection comparing to standard hole style.Such reduction weakened with the increasing of bolt diameter in slotted hole bolt connection.The anti-slip load dropped 11.0%and 4.0%while the mean slip coefficient decreased 12.0%and 10.0%respectively for M20 and M30 slotted hole bolt connection compared with standard hole style under room temperature.4)At 130℃,reductions of slotted hole bolt connection for anti-slip load and mean slip coefficient were 9.0%and 13.0%respectively compared with standard hole style.The reduction was greater at 130℃than room temperature.5)Slotted hole bolt connection would aggravate the relaxation of bolt pre-tension.Reduction of M30 bolt-pre-tension was 16.3%for standard hole connection and 30.7%for slotted hole bolt connection.Difference of 14.4%was observed.6)From 20℃to 130℃,mean slip coefficient of M20 bolt was about 30.0%greater than that of M30 bolt,indicating that the mean slip coefficient improves with the increase of bolt connection stiffness.However,mean slip coefficient of M30 bolt connection was 12.4%smaller than that of M20 bolt connection at 200℃and there was error in the measurement of mean slip coefficient for M20 bolt connection.7)At 130℃,reduction of bolt pre-tension for M20 and M30 bolt connection was 28.4%and 16.3%respectively,indicating that the bolt pre-tension relaxation weakens with the increase of bolt connection stiffness.With the temperature increasing to 200℃,reduction of mean slip coefficient for M20 bolt connection became obvious and greater with higher discreteness than that of 130℃.However,pre-tension of M30 bolt connection showed up and down changes without obvious pattern for temperature rising to 200℃.
作者
侯兆新
龚超
梁梓豪
王罡
姚志东
Zhaoxin Hou;Chao Gong;Zihao Liang;Gang Wang;Zhidong Yao(Central Research Institute of Building and Construction Co.,Ltd.,MCC Group,Beijing 100088,China;National Engineering Research Center on Diagnosis and Rehabilitation of Industrial Building,Shenzhen 518055,China)
出处
《钢结构（中英文）》
2021年第1期50-59,共10页
Steel Construction（Chinese & English）
基金
国家重点研发计划项目(2017YFC0703807)。
关键词
高强度螺栓
槽孔节点
高温
抗滑移系数
螺栓预拉力
high strength bolt
slotted hole
high temperature
mean slip coefficient
bolt pre-tension
作者简介
第一作者:侯兆新,男,1963年出生,硕士,教授级高级工程师;通信作者:龚超,男,1981年出生,博士,教授级高级工程师,gongchao6330@163.com。
