UHPC-窄幅钢箱组合梁抗剪承载力计算方法  

Calculation Method of Shear Capacity of UHPC-narrow Steel Box Composite Beam

作　　者：黄荆 莫时旭[2,3] 郑艳 HUANG Jing;MO Shi-xu;ZHENG Yan(School of Civil Engineering,Chang an University,X'an 710000,China;College of Civil and Architecture Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Key Laboratory of New Energy and Building Energy Saving,Guilin 541004,China)

机构地区：[1]长安大学建筑工程学院,西安710000 [2]桂林理工大学土木与建筑工程学院,桂林541004 [3]广西建筑新能源与节能重点实验室,桂林541004

出　　处：《科学技术与工程》2025年第3期1180-1187,共8页Science Technology and Engineering

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

摘　　要：为改善组合梁负弯矩区易开裂的问题,提出超高性能混凝土-窄幅钢箱组合梁结构,基于极限平衡法以及分项叠加法得到了UHPC-窄幅钢箱组合梁抗剪承载力计算方法。为验证计算方法的准确性,以超高性能混凝土(ultra-high performance concrete,UHPC)层厚度以及钢纤维为变量,设计了1根普通混凝土窄幅钢箱组合梁和3根UHPC-窄幅钢箱组合梁试件,对试验梁进行跨中反向加载试验,得到组合梁负弯矩下的抗剪性能。试验结果表明,相比于普通混凝土窄幅钢箱组合梁,当翼板采用UHPC材料时,翼板中的裂缝分布较为规律,且随着UHPC板厚度的增加,裂缝的分布逐渐呈现竖向等间距分布的特点,当保持翼板的厚度不变,将UHPC层厚度增加50 mm,其屈服荷载增加12.5%,极限荷载增加8.3%,极限荷载对应的挠度值减小了22%。通过分析各试件的屈服挠度以及极限挠度可知,随着UHPC翼板厚度的增加,屈服挠度有逐渐增大的趋势,组合梁弹性阶段所占的比例不断增加。将试验数据与理论计算结果对比分析表明,采用分项叠加法所得的计算结果更能有效地反映UHPC层、普通混凝土层、钢箱、配筋以及充填部分混凝土对于抗剪承载力的贡献,且结果较为精确。In order to improve the problem of easy cracking in the negative moment zone of the composite beam,the UHPC(ultra-high performance concrete)-narrow steel box composite beam structure was proposed,and the shear load capacity calculation method of UHPC-narrow steel box composite beam was obtained based on the ultimate equilibrium method and the sub-stacking method.In order to verify the accuracy of the calculation method,one normal concrete narrow steel box composite beam and three UHPC-narrow steel box composite beam specimens were designed with the thickness of UHPC layer and steel fiber as variables,and the test beams were subjected to mid-span reverse loading test to obtain the shear resistance of the composite beam under negative bending moment.The test results show that compared with the normal concrete narrow steel box composite beam,when the UHPC material is used in the wing slab,the crack distribution in the wing slab was more regular,and with the increase of the thickness of the UHPC slab,the crack dis-tribution gradually shows the characteristic of vertical equidistant distribution,and when the thickness of the wing slab was kept con-stant and the thickness of the UHPC layer was increased by 50 mm,the yield load increases by 12.5%and the ultimate load increases by 8.3%,and the deflection value corresponding to the ultimate load is reduced by 22%.By analyzing the yield deflection as well as the ultimate deflection of each specimen,it can be seen that the yield deflection tends to increase gradually with the increase of UHPC airfoil thickness,and the proportion of the elastic phase of the combined beam keeps increasing.The comparison of the test data with the theoretical calculation results shows that the calculation results obtained by the sub-stacking method can more effectively reflect the contribution of UHPC layer,ordinary concrete layer,steel box,reinforcement and filled part of concrete to the shear load capacity,and the results are more accurate.

关 键 词：超高性能混凝土 抗剪承载力 组合梁 负弯矩 

分 类 号：TU398[建筑科学—结构工程]