窄幅钢箱-UHPC组合梁负弯矩下抗弯性能试验研究  

Experimental study on bending behavior of narrow steel box-UHPC composite beam under negative bending moment

作　　者：郑艳[1,2] 刘晓贝 羊海林 莫时旭[1,2] 黄荆 ZHENG Yan;LIU Xiaobei;YANG Hailin;MO Shixu;HUANG Jing(School of Civil Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China)

机构地区：[1]桂林理工大学土木工程学院,广西桂林541004 [2]桂林理工大学广西岩土力学与工程重点实验室,广西桂林541004

出　　处：《建筑科学与工程学报》2024年第4期42-50,共9页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(52068012);广西自然科学基金项目(2021GXNSFAA220101)。

摘　　要：为改善钢-混凝土组合梁负弯矩下的受力性能,提出一种新型窄幅钢箱-超高性能混凝土(UHPC)组合梁。通过6根试验梁的反向静力加载试验,得到试验梁受力全过程跨中荷载-挠度、荷载-应变、荷载-最大裂缝宽度关系曲线、裂缝发生发展及破坏形态等,基于简化塑性理论推导出了组合梁极限抗弯承载力计算公式。结果表明:窄幅钢箱-UHPC组合梁在负弯矩下具有良好的受力性能;提高配筋率、钢纤维掺量和UHPC相对板厚都可在一定程度上改善组合梁延性,提高其极限抗弯承载力;翼板配筋率对承载力影响较大,配筋率由1%增加至2%时,其极限抗弯承载力提高了15%;钢纤维掺量和UHPC相对板厚对初始开裂荷载影响较大,钢纤维掺量从1%增加到2%时,初始开裂荷载提高32%,UHPC相对板厚由0增加到0.5时,初始开裂荷载提高56%;增加钢纤维掺量和UHPC相对板厚可有效控制裂缝宽度,减少结构主裂缝数量,改善组合梁耐久性;组合梁极限抗弯承载力计算公式计算值与试验值吻合较好,表明塑性理论适用于窄幅钢箱-UHPC组合梁的承载力计算。In order to improve the mechanical behavior of steel-concrete composite beams under negative bending moment,a new narrow steel box-ultra-high performance concrete(UHPC)composite beam was proposed.The reversed static load tests of 6 specimens were completed to obtain the load-deflection curves,load-strain curves,load-maximum crack width curves of midspan,and the crack development and failure pattern of specimens in the whole test process.Based on the simplified plasticity theory,the calculation formula of ultimate flexural capacity of composite beams was derived.The results show that the narrow steel box-UHPC composite beam has good mechanical performance under negative bending moment.Increasing the reinforcement ratio,steel fiber content and UHPC relative plate thickness can improve the ductility and increase the ultimate flexural capacity of composite beams to a certain extent.The reinforcement ratio of flange has great influence on bearing capacity.When the reinforcement ratio increases from 1%to 2%,the ultimate flexural capacity increases by 15%.The initial cracking load is greatly influenced by the steel fiber content and UHPC relative plate thickness.When the steel fiber content increases from 1%to 2%,the initial cracking load increases by 32%.When the UHPC relative plate thickness increases from 0 to 0.5,the initial cracking load is improved by 56%.The increases of steel fiber content and UHPC relative plate thickness can effectively control the crack width,reduce the number of main cracks,and improve the durability of composite beams.The calculated value of the ultimate flexural capacity calculation formula of composite beam is in good agreement with the test data,indicating that the plasticity theory is suitable for the calculation of the bearing capacity of the narrow steel box-UHPC composite beam.

关 键 词：窄幅钢箱-UHPC组合梁 抗弯性能 负弯矩区 静载试验 极限抗弯承载力 

分 类 号：TU375[建筑科学—结构工程]