摘要
在北方寒冷地区,钢管混凝土结构因冻融作用侵蚀而造成钢管开裂以及钢管混凝土结构力学性能劣化从而导致结构破坏的事故时有发生。针对冻融侵蚀后钢管混凝土界面黏结性能问题,制作了钢管混凝土推出试件,考虑冻融循环次数、混凝土强度、钢管径厚比等不同参数,进行冻融试验和推出试验,分析了界面黏结力的分布规律和影响因素,研究了冻融循环作用后钢管混凝土界面黏结滑移本构关系,确定了界面平均黏结强度以及峰值黏结强度、残余黏结强度特征值。结果表明,随着冻融循环次数的增加,界面平均黏结强度减小,极限荷载对应的滑移逐渐增大,而残余黏结强度呈线性减小,稳定段起点滑移随着冻融循环次数的增加呈指数增长。峰值黏结强度、残余黏结强度随混凝土强度的增加而提高,随着径厚比的增大而降低。分析外钢管密布应变计所测出的应变分布规律可知界面黏结应力呈指数分布,对比分析由荷载、滑移结合能量法理论推导所得的黏结应力分布函数,结果表明其具有较高精度,为后期研究界面黏结性能提供了新思路。构建了冻融循环作用后界面黏结应力-滑移三段式本构模型,并提出了相应特征值计算公式和本构模型,可为该类构件设计时考虑冻融作用提供参考。
In the cold area of north China,the concrete-filled steel tubular structure is eroded by freeze-thaw action,which causes the cracking of steel tube and the deterioration of mechanical properties of concrete-filled steel tubular structure.Aiming at the problem of interfacial bonding performance of concrete-filled steel tube under freeze-thaw erosion,freeze-thaw cycle test and push-out test of concrete-filled steel tube were carried out.Considering the different parameters such as the number of freeze-thaw cycles,concrete strength and the diameter-thickness ratio of steel tube,the distribution law and influencing factors of interfacial bonding force were analyzed,and the interfacial bond-slip constitutive relationship of concrete-filled steel tube under freeze-thaw cycles was studied.The average bond strength,peak bond strength and residual bond strength were determined.The results show that with the increase of the number of freeze-thaw cycles,the average interfacial bond strength decreases,the slip corresponding to the ultimate load increases gradually,while the residual bond strength decreases linearly,and the initial slip of the stable section increases exponentially.The peak bond strength and residual bond strength increase with the increase of concrete strength,and decrease with the increase of diameter-thickness ratio.By analyzing the strain distribution law measured by the dense strain gauges of the outer steel tube,it can be seen that the interfacial bond stress obeys exponential distribution.The bond stress distribution function derived from the load and slip combined energy method is compared and analyzed with good precision,which provides a new idea for the later experimental study of the interfacial bonding performance.A three-stage constitutive model of interfacial bond stress-slip after freeze-thaw cycles was constructed,and the corresponding eigenvalue calculation formula and constitutive model equation were proposed,which may provide reference for the design of concrete-filled steel tubular members considering freeze-thaw action.
作者
曾在平
王宇航
王秀丽
任根立
ZENG Zaiping;WANG Yuhang;WANG Xiui;REN Geni(Gansu Vocational College of Architecture,Lanzhou 730050,China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China)
出处
《建筑钢结构进展》
CSCD
北大核心
2024年第9期53-64,共12页
Progress in Steel Building Structures
基金
2023年甘肃省高校青年博士支持项目(2023QB-104)
甘肃省住房和城乡建设厅2024年建设科技项目(JK2024-34)。
关键词
钢管混凝土
冻融作用
推出试验
界面黏结应力-滑移本构
黏结应力分布函数
concrete-filled steel tube
freeze-thaw action
push-out test
interfacial bond stress-slip constitutive model
bond stress distribution function
