摘要
为了明确预应力轻质超高性能混凝土(Lightweight Ultra-high Performance Concrete,简称LUHPC)梁的抗弯性能,设计制作了9根预应力LUHPC梁,通过改变非预应力受拉钢筋和受压钢筋配筋率、预应力大小以及LUHPC的钢纤维掺量等参数,对其进行抗弯性能试验,研究各种参数对预应力LUHPC梁的破坏形态、荷载-挠度曲线、开裂弯矩、极限承载力和延性的影响规律。将预应力LUHPC梁受压区应力图形简化为三角形,并考虑受拉区混凝土拉应力作用,推导了预应力LUHPC梁抗弯极限承载力计算公式。结果表明:当非预应力受拉钢筋配筋率从0.46%增大到1.20%时,其抗弯承载力提高48%,预应力从169kN增大到507kN时,其抗弯极限承载力提高46%,开裂弯矩提高83.5%。提出的抗弯极限承载力计算公式,计算值与试验值比较一致,可为预应力LUHPC梁设计计算提供参考。
In order to determine the flexural performance of pre-stressed lightweight ultra-high performance concrete(LUHPC)beams,9 prestressed LUHPC beams were designed and manufactured in this paper.By changing the ratio of ordinary steel in the tension zone,the ratio of ordinary steel in the compression zone,the size of the pre-stress and the amount of steel fiber in the concrete,the influence of the prestressed LUHPC beam’s failure form,load-displacement curve,steel reinforcement ratio,pre-stress and steel fiber content on its cracking moment,ultimate bearing capacity and ductility is studied.A calculation formula for the flexural bearing capacity of pre-stressed LUHPC beams is proposed,which simplifies the stress graph in the compression zone into a triangle and takes into account the contribution of the concrete tensile stress in the tension zone.The results show that when the reinforcement ratio of the tension zone increases from 0.46%to 1.20%,its ultimate flexural bearing capacity is increased by 48%,and when the number of prestressed tendons increases from 1 to 3,its ultimate flexural bearing capacity is increased by 46%,cracking moment is increased by 83.5%.The proposed formula for the ultimate flexural bearing capacity of prestressed LUHPC beams,the calculated value is consistent with the experimental value,which can provide a reference for the design and calculation of prestressed LUHPC beams.
作者
刘沐宇
邱儆
张强
LIU Mu-yu;QIU Jing;ZHANG Qiang(Hubei Key Laboratory of Roadway Bridge&Structure Engineering,Wuhan University of Technology,Wuhan 430070,China;China Railway Major Bridge Reconnaissance&Design Institute Group Co Ltd,Wuhan 430050,China)
出处
《武汉理工大学学报》
CAS
2021年第9期13-19,共7页
Journal of Wuhan University of Technology
基金
湖北省技术创新专项(重大项目)(2018AAA-001)。
关键词
轻质高性能混凝土
抗弯性能
预应力
抗弯极限承载力
配筋率
lightweight ultra-high performance concrete
flexural performance
prestressed
ultimate bearing capacity
reinforcement ratio
