摘要
面向高烈度地震区既有钢筋混凝土(RC)桥墩抗震性能不足的加固需求,提出了一种超高性能混凝土(UHPC)的新型钢管约束加固技术;为探究该新型加固墩柱的抗震性能,以加固类型和初始轴压比为研究参数,拟静力试验研究了5根试件的破坏模式、滞回曲线、骨架曲线及抗震性能指标;以试验结果作为验证依据,建立了能准确模拟钢管约束UHPC加固RC柱滞回性能的有限元模型,继而借助有限元对加固层的UHPC厚度、UHPC强度和钢管厚度进行了参数拓展分析。研究结果表明:RC柱经钢管约束UHPC加固后,塑性铰区减小,且集中于柱脚钢管切缝处;与UHPC增大截面加固法相比,同条件下钢管约束UHPC加固柱的位移延性系数、累计滞回耗能和初始刚度均得到更明显提高,残余变形则减小更为显著;随着初始轴压比在0~0.3范围增大,钢管约束UHPC加固柱的破坏模式、承载力和耗能能力等无明显变化,但位移延性系数和初始刚度有所减小,残余位移趋于增大;提高加固层UHPC的强度,可明显提升加固柱的耗能能力;增加加固层钢管的厚度,则有利于显著减小加固柱的残余位移;增大加固层UHPC的厚度,加固柱的承载力、位移延性系数、累计滞回耗能和初始刚度均有明显提高,同时其残余位移显著减小。以上研究成果可为钢管约束UHPC预防性抗震加固既有RC墩柱的应用奠定理论基础。
To address the seismic retrofitting demand for existing reinforced concrete(RC)bridge piers in high-intensity seismic regions,a novel strengthening technique using steel tube-confined ultra-high performance concrete(UHPC)was proposed.To investigate the seismic performance of the newly strengthened piers,quasi-static tests were conducted on five specimens,with strengthening type and initial axial load ratio as parameters.Failure modes,hysteretic curves,skeleton curves,and seismic performance indices were measured.Then,based on the experimental results,a finite element model was built to accurately simulate the quasi-static behavior of the strengthened columns.Subsequently,parametric analyses were carried out using finite element simulations,considering the UHPC layer thickness,UHPC strength,and steel tube thickness.Research results show that after strengthening with steel tube-confined UHPC,the plastic hinge region of the RC columns was reduced and concentrated near the cut in the steel tube at the column base.Compared with the UHPC section enlargement method,the steel tube-confined UHPC strengthening technique provides greater improvement in displacement ductility coefficient,cumulative hysteretic energy dissipation,and initial stiffness,along with a more significant reduction in residual deformation under the same conditions.As the initial axial load ratio increases within the range of 0-0.3,the failure mode,bearing capacity,and energy dissipation capacity remain largely unchanged.However,displacement ductility and initial stiffness decrease,and residual displacement tends to increase.Increasing the UHPC strength in the strengthening layer significantly improves the energy dissipation capacity.Increasing the thickness of the steel tube in the strengthening layer significantly reduces the residual displacement.Increasing the UHPC thickness in the strengthening layer enhances bearing capacity,displacement ductility,cumulative hysteretic energy dissipation,and initial stiffness,while also markedly reducing residual displacement.These findings are expected to provide a theoretical basis for the application of steel tube-confined UHPC in the preventive seismic strengthening of existing RC bridge piers.
作者
罗霞
余昕烨
韦建刚
杨艳
杨毅林
LUO Xia;YU Xin-ye;WEI Jian-gang;YANG Yan;YANG Yi-lin(School of Civil Engineering,Fujian University of Technology,Fuzhou 350118,Fujian,China;College of Civil Engineering,Fuzhou University,Fuzhou 350108,Fujian,China;Department of Civil Engineering,Fuzhou University Zhicheng College,Fuzhou 350002,Fujian,China)
出处
《交通运输工程学报》
北大核心
2025年第5期234-249,共16页
Journal of Traffic and Transportation Engineering
基金
国家自然科学基金项目(52278158)
福建省自然科学基金项目(2022J05188)
福建理工大学科技项目(GY-Z20174,GY-Z21220)。
关键词
桥梁工程
抗震性能
拟静力试验
加固
钢筋混凝土柱
钢管约束混凝土
超高性能混凝土
bridge engineering
seismic performance
quasi-static test
strengthening
reinforced concrete column
steel tube-confined concrete
ultra-high performance concrete
