高强方钢管UHPC构件轴向冲击与冲击后剩余性能  

Axial Impact and Residual Behavior of UHPC-filled High-strength Square Steel Tubular Members

作　　者：杨晓强 张强 赖志超 陈剑清 马文硕 YANG Xiao-qiang;ZHANG Qiang;LAI Zhi-chao;CHEN Jian-qing;MA Wen-shuo(College of Civil Engineering,Fuzhou University,Fuzhou 350116,Fujian,China)

机构地区：[1]福州大学土木工程学院,福建福州350116

出　　处：《中国公路学报》2024年第5期234-245,共12页China Journal of Highway and Transport

基　　金：国家自然科学基金青年基金项目(52108122);福建省自然科学基金青创项目(2022J05022)。

摘　　要：冲击具有作用源多样、低频多发、危害性大等鲜明特征,已成为桥梁垮塌的主要原因之一。高强钢管超高性能混凝土(UHPC)作为大跨高墩桥梁的优选构件之一,其受冲击作用的风险不可忽视。设计制作了9根高强方钢管UHPC短柱,以期研究其轴向冲击性能及冲击后剩余性能。采用落锤试验机和液压试验机分别开展轴向冲击试验及冲击后剩余承载力试验,主要考虑冲击能量和钢纤维掺量2种参数,探究冲击力、变形、能量吸收、剩余承载力和剩余率等关键性能指标的变化规律。结果表明:高强钢管UHPC构件的抗冲击性能和剩余性能明显优于高强钢管高强混凝土构件,能够应对更大能量的轴向冲击作用;钢纤维与混凝土基体之间的黏结锚固作用及其形成的纤维网骨架能有效提高UHPC的强度、抗裂性、延性与耗能能力,这一特性使得构件在冲击作用下的峰值位移和残余变形随着钢纤维掺量的增加而显著降低;2%钢纤维掺量时,峰值位移与残余变形的降低幅度分别可达14.3%和31.4%,单位变形耗能最大提升了38.4%;在未发生严重损伤的情况下,构件的剩余承载力和剩余率随着钢纤维掺量的增加显著提高,分别可达28.3%和12.4%;在0~2%范围内,钢纤维体积掺量的增加可显著提高钢管混凝土构件的抗轴向冲击性能与冲击后剩余力学性能。需要指出,考虑的钢纤维掺量仅针对工程设计中常用范围,超出研究范围时需进一步论证分析。Impacts have the distinctive characteristics of diverse conditions,low frequency,repeated occurrence,and high hazard;as such,they have emerged as a leading factor in bridge collapses.Ultra-high-performance concrete(UHPC)-filled high-strength steel tubular members are the preferred choice for large-span and high-pier bridges whose vulnerability to impacts cannot be ignored.Nine UHPC-flled high-strength square steel tubular specimens were designed in this study to explore their axial impact resistances and residual bearing capacities using a drop hammer and a hydraulic testing machine,respectively.The influence of impact energy and UHPC steel fiber content on key performance indicators including impact force,deformation,energy absorption,residual capacity,and residual rate were subsequently evaluated.The results show that the impact resistance and residual capacity of a UHPC-filled high-strength steel tubular member are significantly higher than those of a high-strength concrete-filled high-strength steel tubular member and that UHPC members can withstand greater levels of axial impact energy.Furthermore,the strong bonding behavior between the steel fibers and concrete matrix,as well as the resulting fiber network skeleton,can effectively improve the strength,crack resistance,ductility,and energy dissipation capacity of UHPC.Indeed,the incorporation of steel fibers significantly reduces the peak displacement and residual deformation of components subjected to axial impact by up to 14.3%and 31.4%,respectively,and an increase in steel fiber volume content from 0%to 2%increases the energy absorption per unit deformation by 38.4%.In addition,when a specimen does not suffer severe damage from the axial impact,its residual bearing capacity and residual rate increase significantly by up to 28.3%and 12.4%,respectively.Therefore,an appropriate increase in fiber content(up to 2%)can improve the axial impact resistance and residual bearing capacity of a UHPC-filled high-strength square steel tubular member.However,the stel fi

关 键 词：桥梁工程 轴向冲击 试验研究 剩余承载力 高强钢管 UHPC 钢纤维体积掺量 

分 类 号：U441.2[建筑科学—桥梁与隧道工程]