摘要
为了探讨超高性能混凝土-充填式窄幅钢箱组合梁裂缝发展规律和分布,评估现行规范中最大裂缝宽度计算公式对该类组合梁的适用性,考虑组合梁钢纤维掺量、充填混凝土高度和配筋率3个因素,对6根该类组合梁开展弯曲试验;根据超高性能混凝土的特性,提出该类组合梁钢筋应力计算方法;修正现行规范中最大裂缝宽度计算公式,并考虑钢纤维掺量的影响,建立该类组合梁的最大裂缝宽度计算公式。结果表明:组合梁开始出现裂缝后最大裂缝宽度发展较缓慢,在最大裂缝宽度达到0.16 mm之前,荷载等级-最大裂缝宽度曲线大致呈线性,组合梁屈服后裂缝宽度迅速增大;增加钢纤维掺量和配筋率可明显限制裂缝发展,钢箱充填超高性能混凝土可明显增强组合梁极限承载能力;现行规范中最大裂缝宽度公式计算该类组合梁最大裂缝宽度过于保守,所提出该类组合梁钢筋应力计算方法和组合梁最大裂缝宽度公式的计算值与弯曲试验实测值均吻合较好。
To investigate crack development law and distribution of ultra-high performance concrete-filled narrow steel box composite beams,and evaluate applicability of maximum crack width calculation formulas in current specifications for this type of composite beams,bending test was carried out on six composite beams of this type considering three factors of steel fiber content,filled concrete height,and reinforcement ratio of the composite beams.According to characteristics of ultra-high performance concrete,a steel bar stress calculation method of this type of composite beams was proposed.Calculation formulas of maximum crack width in current specifications were corrected,and a maximum crack width formula of this type of composite beams was established considering influences of steel fiber content.The results show that the maximum crack width develops slowly after cracks begin to appear in the composite beams.Before the maximum crack width reaches 0.16 mm,the load grade-maximum crack width curve is roughly linear,and the crack width increases rapidly after the composite beams yield.The increase of steel fiber content and reinforcement ratio can signifi-cantly limit the crack development.Filling ultra-high performance concrete in the box can significantly improve ultimate bearing capacity of composite beams.The formulas in current specification are too conservative to calculate maximum crack width of this type of composite beams.Calculated values of the proposed steel bar stress calculation method and the proposed formula for the maximum crack width of this type of composite beams are in good agreement with measured values of bending test.
作者
农双秀
莫时旭
郑艳
房洋洋
NONG Shuangxiu;MO Shixu;ZHENG Yan;FANG Yangyang(College of Civil Engineering,Guilin University of Technology,Guilin 541004,Guangxi,China;Guangxi Key Laboratory of Green Building Materials and Construction Industrialization,Guilin University of Technology,Guilin 541004,Guangxi,China)
出处
《济南大学学报（自然科学版）》
CAS
北大核心
2024年第6期738-748,共11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
裂缝宽度
弯曲试验
超高性能混凝土
充填式窄幅钢箱
composite beam
crack width
bending test
ultra-high performance concrete
filled narrow steel box
