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
郑艳 1刘晓贝 2羊海林 1莫时旭 1黄荆2
作者信息
- 1. 桂林理工大学 土木工程学院,广西 桂林 541004;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
- 2. 桂林理工大学 土木工程学院,广西 桂林 541004
- 折叠
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.
Abstract
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Key words
narrow steel box-UHPC composite beam/bending behavior/negative bending mo-ment region/static load test/ultimate bending capacity引用本文复制引用
基金项目
国家自然科学基金项目(52068012)
广西自然科学基金项目(2021GXNSFAA220101)
出版年
2024
NETL
NSTL
万方数据