UHPC-T梁抗弯性能试验研究与理论计算  

Experimental study and theoretical calculation on flexural performance of UHPC-T beams

作　　者：朱琦 叶力豪 蔡玮[1] 谢文[1] ZHU Qi;YE Lihao;CAI Wei;XIE Wen(School of Civil&Environmental Engineering and Geography Science,Ningbo University,Ningbo 315211,Zhejiang,China)

机构地区：[1]宁波大学土木工程与地理环境学院,浙江宁波315211

出　　处：《建筑科学与工程学报》2023年第1期65-74,共10页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(52278189);宁波市自然科学基金项目(202003N4138)。

摘　　要：为研究配筋率和预应力对超高性能混凝土T梁(UHPC-T梁)抗弯性能的影响,设计并制作了4根UHPC-T梁与1根普通混凝土T梁,采用三等分点抗弯试验研究了T梁加载破坏的全过程特征,并采用理论公式计算了T梁的开裂弯矩和极限弯矩等关键性能参数。结果表明:配筋率对UHPC-T梁开裂荷载的影响不大;相同配筋率下,预应力UHPC-T梁的极限承载力约为UHPC-T梁的1.4倍,UHPC-T梁的极限承载力约为普通混凝土T梁的2倍,表明预应力和UHPC均可明显提升T梁的极限承载能力;与普通混凝土T梁相比,UHPC-T梁裂缝细而密,加载初期最大裂缝宽度发展较慢,裂缝宽度及其数量明显减少;与UHPC-T梁相比,预应力UHPC-T梁能有效抑制裂缝的生成与发展,表明预应力和UHPC能改善T梁的抗裂性能;各试验梁跨中正截面混凝土应变与荷载基本呈正比例关系,表明平截面假定同样适用于预应力UHPC-T梁与UHPC-T梁;T梁的理论开裂弯矩和极限弯矩均与相应的试验结果吻合较好,且两者之间的相对误差小于20%,满足工程设计要求。In order to study the influence of reinforcement ratio and prestress on the flexural performance of ultra-high performance concrete T-beam(UHPC-T beam), four UHPC-T beams and one ordinary concrete T-beam were designed and manufactured. The whole process characteristics of T-beam loading failure were studied by three-point bending test, and the key performance parameters such as cracking moment and ultimate bending moment of T-beam were calculated by theoretical formula. The results show that the reinforcement ratio has little effect on the cracking load of UHPC-T beam. Under the same reinforcement ratio, the ultimate bearing capacity of prestressed UHPC-T beam is about 1.4 times that of UHPC-T beam, and the ultimate bearing capacity of UHPC-T beam is about 2 times that of ordinary concrete T beam, indicating that both prestress and UHPC can significantly improve the ultimate bearing capacity of T beam. Compared with the ordinary concrete T beam, the cracks of UHPC-T beam are fine and dense, the maximum crack width develops slowly at the initial stage of loading, and the crack width and its number are significantly reduced. Compared with UHPC-T beam, prestressed UHPC-T beam can effectively inhibit the generation and development of cracks, indicating that prestress and UHPC can improve the crack resistance of T beam. The strain of normal section concrete in the mid-span of each test beam is basically proportional to the load, indicating that the plane section assumption is also applicable to prestressed UHPC-T beams and UHPC-T beams. The theoretical cracking moment and ultimate bending moment of T beam are in good agreement with the corresponding test results, and the relative error between them is less than 20%, which meets the engineering design requirements.

关 键 词：UHPC-T梁 抗弯性能 开裂弯矩 极限弯矩 后张预应力 

分 类 号：TU375.1[建筑科学—结构工程]