加速锈蚀下栓钉剪力连接件的疲劳性能试验研究  

Experimental investigation on fatigue properties of stud shear connectors subjected to accelerated corrosion

作　　者：匡亚川[1] 彭志威 蔡航航 王坤 KUANG Yachuan;PENG Zhiwei;CAI Hanghang;WANG Kun(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2024年第11期4702-4710,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52378210,51878663);湖南省自然科学基金资助项目(2023JJ30674);中南大学中央高校基本科研业务费专项资金资助项目(2023ZZTS0408)。

摘　　要：栓钉是钢-混凝土组合梁桥中应用最广泛的一种剪力连接件,因受到环境腐蚀作用,栓钉剪力连接件的疲劳性能会发生退化。为研究锈蚀对栓钉疲劳性能的影响规律,设计并制作了9个推出试件,采用恒定电流方法加速锈蚀试件中的栓钉,通过推出试件的恒幅疲劳试验,研究分析不同锈蚀程度下栓钉的疲劳寿命以及混凝土与钢梁界面的滑移性能。试验结果表明:在疲劳荷载作用下,所有推出试件的破坏模式均为栓钉剪切破坏,栓钉的疲劳断裂面可分成疲劳裂纹扩展区和静力破坏区2个特征明显不同的区域,其中疲劳裂纹扩展区形状类似月牙形。锈蚀会减少栓钉的截面积,当疲劳荷载幅值相同时会增大栓钉承受的剪应力幅值,此外,锈坑处的应力集中效应会加快疲劳裂纹的扩展速率,从而显著影响栓钉的疲劳寿命,栓钉的疲劳寿命随着锈蚀率的增大近似按指数规律衰减,当锈蚀率达到13%左右时,疲劳寿命减少了80%以上。混凝土与钢梁界面的塑性滑移曲线形式与栓钉的锈蚀程度直接相关,锈蚀率较小时,塑性滑移曲线可分成线性缓慢增长和指数快速增长2个阶段,而锈蚀率较大时,塑性滑移曲线呈单一的指数形式。锈蚀不仅会降低栓钉的抗剪刚度,还会加快抗剪刚度的退化速度。研究结果可为钢-混凝土组合梁桥的安全运营提供参考。Studs are the most widely used shear connectors in steel-concrete composite girder bridges.The fatigue properties of stud shear connectors will be degraded by the environmental corrosion effect.To investigate the influence of corrosion on the fatigue properties of studs,nine push-out specimens were designed and fabricated.The constant current method was adopted to accelerate the studs in the push-out specimens.Through the constant amplitude fatigue tests on the push-out specimens,the fatigue life of studs and the slip properties at the interface between concrete and steel beams under different corrosion ratios were investigated and analyzed.Based on the tests,the results are drawn as follows.The failure modes of all specimens are stud shear failure under fatigue load.The fatigue fracture surface of the stud consists of two regions with obviously different characteristics,namely,the fatigue crack extension region and the static damage region,and the shape of the fatigue crack extension region resembles a crescent shape.Corrosion can reduce the cross-sectional area of the stud,thereby increasing the shear stress amplitude of the stud when the external load amplitude conditions are identical.Furthermore,the stress concentration effect at the corrosion pit can accelerate the expansion rate of fatigue cracks,thus significantly affecting the fatigue life of the stud.The fatigue life of the stud decreases approximately exponentially with the corrosion ratio,experiencing a reduction of more than 80%when the corrosion ratio reaches about 13%.The form of the plastic slip curve at the interface between concrete and steel beam is directly related to the corrosion level of the stud.When the corrosion ratio is low,the plastic slip curve can be divided into two stages of linear slow growth and exponential rapid growth.However,the plastic slip curve turns into a single exponential form when the corrosion ratio is high.Corrosion can not only reduce the shear stiffness of stud,but also accelerate the degradation rate of shear stif

关 键 词：钢-混凝土组合梁 栓钉剪力连接件 疲劳性能 试验研究 锈蚀 

分 类 号：TU398[建筑科学—结构工程]