方钢管约束超高强混凝土短柱轴压承载力试验研究  

Experimental Study on Axial Compression Bearing Capacity of Square Steel Tube Confined UHSC Short Column

作　　者：施伯超 SHI Bo-chao(Fuzhou Metro Construction Engineering Quality and Safety Supervision Station,Fuzhou,Fujian 350007,China)

机构地区：[1]福州市地铁建设工程质量安全监督站,福建福州350007

出　　处：《公路交通科技》2024年第9期180-189,共10页Journal of Highway and Transportation Research and Development

基　　金：福建省科技厅工业高校产学合作项目(2022H6009)。

摘　　要：为探究方钢管约束超高强混凝土(UHSC)短柱的轴压受力机理与极限承载力计算方法的准确性,以混凝土抗压强度、钢材屈服强度、含钢率为参数,开展了试验研究和有限元分析;依据约束机理提出了短柱轴压极限承载力计算方法。结果表明:套箍系数是影响方钢管约束UHSC短柱轴压破坏模式的主要因素,小于0.83时表现为剪切破坏,大于等于0.83时表现为压溃破坏;通过荷载-位移曲线与荷载-应变曲线发现,在极限荷载前钢管的环向约束能力未被充分发挥,约束作用主要表现在极限荷载后,增加含钢率可有效提高试件破坏后的受压延性,含钢率最小的试件均出现荷载突降的现象,在设计方钢管约束UHSC短柱时,需要根据混凝土抗压强度匹配合适的约束力;由于普通混凝土与UHSC压拉比不同,在核心混凝土临近极限荷载前,UHSC塑性发展程度更低,降低了与钢管之间的相互作用,所以方钢管约束UHSC短柱极限荷载提高幅度小于内填普通混凝土的试件;基于Mander模型与中国标准的计算方法无法对套箍系数大于0.3的内填UHSC试件做出准确的评估,中国标准的计算误差更小,依据试验与有限元分析结果,引入约束折减系数后,可将计算偏差控制在10%以内。To investigate the axial compression mechanism and the accuracy of ultimate bearing capacity calculation method for ultra-high strength concrete(UHSC)short columns confined with square steel tubes,the experimental study and finite element analysis were conducted by using concrete compressive strength,steel yield strength,and steel content as parameters.The calculation method for ultimate bearing capacity of short columns under axial compression was proposed based on the constraint mechanism.The result indicates that the hoop coefficient is the main factor affecting the axial compression failure mode of UHSC short columns restrained with square steel tubes.When it is less than 0.83,exhibiting shear failure;when it is over or equal 0.83,exhibiting compression failure.Through the load-displacement curves and load-strain curves,it is found that the circumferential restraining ability of steel tube is not fully utilized before the ultimate load,and the restraining effect is mainly manifested after the ultimate load.Increasing the steel content can effectively improve the compressive ductility of specimen after failure.The specimen with the lowest steel content show the sudden drop in load.When designing the steel tube to restrain UHSC short columns,it is necessary to match the appropriate restraining force according to the compressive strength of concrete.Due to the different compression ratios between ordinary concrete and UHSC,the plastic development of UHSC is lower before the core concrete approaches the ultimate load,which reduces the interaction between UHSC and steel tubes.Therefore,the increase in ultimate load of UHSC short columns restrained by square steel tube is smaller than that of specimens filled with ordinary concrete.The calculation method based on Mander model and China’s standards cannot accurately evaluate the filled UHSC specimens with the hoop coefficient over 0.3.The calculation errors with China’s standards are less.Based on experimental and finite element analysis results,the introduction

关 键 词：桥梁工程 承载力计算 试验研究 钢管约束混凝土 方钢管 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]