摘要
为了研究超高性能混凝土-充填式窄幅钢箱组合梁在负弯矩作用下的力学性能,以超高性能混凝土中掺加钢纤维的体积分数、翼板中超高性能混凝土层的厚度、窄幅钢箱梁中充填普通混凝土的高度为变量,设计6根组合梁开展反向静力加载试验;利用ABAQUS软件模拟并分析充填普通混凝土的作用机制,在考虑滑移效应的条件下推导组合梁的挠度曲线解析式,提出简化的折减刚度系数。结果表明:组合梁的破坏模式均为弯曲破坏,翼板与窄幅钢箱梁之间存在滑移效应并均符合平截面假定;相比普通混凝土翼板,在翼板中引入超高性能混凝土层可以减少贯通主裂缝,超高性能混凝土中不同的掺加钢纤维的体积分数使组合梁的开裂荷载增大74.7%~231.5%,裂后刚度增大10.75%~19.9%;充填普通混凝土能有效防止加载点处窄幅钢箱梁的局部屈曲,充填普通混凝土的有效受压高度为腹板高度的1/5~1/7;考虑滑移效应及翼板开裂对组合梁刚度的影响,当采用所提出的简化的折减刚度系数并以双折线的形式分段计算组合梁的跨中挠度时,屈服荷载下跨中挠度计算值与试验值的平均误差为5.85%,当忽略翼板开裂而仅考虑滑移效应时,跨中挠度计算值与试验值的平均误差为11.92%。
To research mechanical properties of ultra-high performance concrete-filled narrow steel box composite beams under negative bending moments,reverse static loading tests were conducted on six test beams taking volume fraction of steel fiber in ultra-high performance concrete,thickness of ultra-high performance concrete layer in flange,and height of filled normal concrete in narrow steel box beams as variables.Action mechanism of filled normal concrete was analyzed by using ABAQUS software.An analytical formula for deflection curve of composite beams was derived considering slip effect,and a simplified reduction stiffness coefficient was proposed.The results show that failure modes of the composite beams are bending failure.There is slip effect between the flange and the narrow steel box girder,and both of them conform to plane section assumption.Compared with normal concrete flanges,introducing ultra-high performance concrete layer into the flanges can reduce main through cracks.Different volume fractions of steel fiber in ultra-high performance concrete increase cracking load of composi te beams by 74.7% to 231.5%,an d post-cracking stiffness by 10.75% to 19.9%.The filled normal concrete can effectively prevent local buckling of the narrow steel box girder at loading points,and effective compression height of the filled normal concrete is 1/5 to 1/7 of web plate height.Considering impacts of slip effect and flange cracking on stiffness of composite beams,when the proposed simplified reduction stiffness coefficient is adopted and mid-span deflection of composite beams is calculated in segments with a bilinear form,the average error between the calculated value and the test value of mid-span deflection under yield load is 5.85%.When flange cracking is ignored and only slip effect is considered,the average error between the calculated value and the test value of mid-span deflection is 11.92%.
作者
檀新宁
郑艳
祝俊祥
莫时旭
TAN Xinning;ZHENG Yan;ZHU Junxiang;MO Shixu(Guangxi Key Laboratory of Green Building Materials and Construction Industrialization,Guilin University of Technology,Guilin 541004,Guangxi,China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China)
出处
《济南大学学报(自然科学版)》
北大核心
2025年第6期880-890,898,共12页
Journal of University of Jinan(Science and Technology)
基金
国家自然科学基金项目(52068012)
广西自然科学基金项目(2021GXNSFAA220101)
广西绿色建材与建筑工业化重点实验室项目(桂科能22-J-21-1)。
关键词
组合梁
刚度
反向静力加载试验
超高性能混凝土
滑移效应
composite beam
stiffness
reverse static loading test
ultra-high performance concrete
slip effect
