摘要
采用试验方法进行超高性能混凝土(UHPC)增强普通混凝土复合梁的受弯承载力研究,并基于细观力学理论提出复合梁受弯承载力计算式。结果表明:加载过程中复合梁截面应变与截面高度呈较好的线性关系,复合梁满足平截面假定;复合梁受弯破坏过程包括弹性阶段、裂缝阶段和破坏阶段3个阶段;增大UHPC高度,复合梁从裂缝出现到破坏的时间明显增加,且破坏时梁体裂缝明显增多、增长,呈多缝开裂状态,破坏形态趋于塑性破坏;复合梁受弯承载力随UHPC高度的增加而增大,当UHPC高度超过截面高度的一半后,复合梁受弯承载力增大的速度减缓,而后保持不变;复合梁受弯承载力计算式考虑了UHPC高度、纤维率、纤维长度和抗压强度的影响,具有较高的计算精度。
The flexural capacity of Ultra-High Performance Concrete(UHPC)reinforced ordinary concrete composite beams was experimentally studied,and the calculation formula for the flexural capacity of composite beams was proposed based on meso-mechanics theory.The results show that there is a good linear relationship between the cross-section strain and the section height of the composite beam in the loading process,and the composite beam satisfies the flat section assumption.The flexural failure of composite beams includes three stages:elastic stage,crack stage and failure stage.With the increase of UHPC height,the time from crack appearance to the failure of the composite beam increases obviously,and the cracks in the beam body increase and grow significantly,showing a state of multi-slit cracking.The failure mode tends to plastic failure.The flexural capacity of composite beams increases with the increase of UHPC height.When the UHPC height exceeds half of the section height,the increase rate of the composite beam flexural capacity slows down and remains constant.The calculation formula for the flexural capacity of composite beams considers the UHPC height,fiber ratio,fiber length and flexural compressive strength,which has a high calculation accuracy.
作者
雒敏
蔺鹏臻
杨子江
LUO Min;LIN Pengzhen;YANG Zijiang(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou Gansu 730070,China)
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2021年第5期21-29,共9页
China Railway Science
基金
国家自然科学基金高铁联合基金资助项目(U1934205)
国家自然科学基金重大项目(11790281)
甘肃省建设科技攻关项目(JK2021-03)
兰州交通大学青年科学基金资助项目(2016015)。
关键词
复合梁
超高性能混凝土
受弯承载力
应变
UHPC高度
试验
Composite beam
Ultra-high performance concrete
Flexural capacity
Strain
UHPC height
Experiment
