考虑多影响因素的配筋UHPC梁裂缝宽度计算方法  

Calculation method for crack width of reinforced UHPC beams considering multiple influencing factors

作　　者：孙永新 蔺鹏臻[1,2] 杨子江[1] 王亚朋[1] Sun Yongxin;Lin Pengzhen;Yang Zijiang;Wang Yapeng(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Road&Bridge and Underground Engineering of Gansu Province,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院,兰州730070 [2]兰州交通大学甘肃省道路桥梁与地下工程重点实验室,兰州730070

出　　处：《东南大学学报（自然科学版）》2023年第4期628-636,共9页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金高铁联合基金资助项目(U1934205);兰州交通大学青年科学基金资助项目(2020007).

摘　　要：为建立适用于配筋超高性能混凝土(UHPC)梁的裂缝宽度计算方法,对8片UHPC-T形梁开展了四点抗弯试验,分析钢纤维体积分数、配筋率及保护层厚度对裂缝宽度的影响规律.基于钢筋-UHPC协同受力和变形协调机理,采用半理论半经验法构建了能综合反映多影响因素的最大裂缝宽度计算公式,并提出了适用于UHPC梁的钢筋应力、应变不均匀系数及平均裂缝间距计算方法.结果表明:在试验范围内,裂缝宽度随纤维体积分数、配筋率的提高而减小,随保护层厚度增加而增大;UHPC梁的钢筋应变不均匀程度大于普通混凝土梁;平均裂缝间距计算值与文献实测值最大相对误差为11.17%,最大裂缝宽度计算值与实测值、文献实测值之比的均值分别为1.02、1.01,变异系数分别为0.05、0.12,表明所提出公式可准确计算配筋UHPC梁的最大裂缝宽度.To establish the crack width calculation method suitable for reinforced ultra-high performance concrete(UHPC)beams,four-point flexural tests were carried on 8 UHPC-T beams,and the effects of steel fiber volume ratio,reinforcement ratio and protective layer thickness on crack width were analyzed.Based on the mechanism of synergistic stress and deformation coordination between reinforcement and UHPC,a semi theoretical and semi empirical method was used to construct a formula for calculating the maximum crack width that can comprehensively reflect multiple influencing factors.And the calculation methods for the steel stress,the strain non-uniformity coefficient and the average crack spacing suitable for UHPC beams were proposed.The results show that within the test range,the crack width decreases with the increase of fiber volume fraction and reinforcement ratio,and increases with the increase of protective layer thickness.The non-uniformity of steel strain in UHPC beams is greater than that in ordinary concrete beams.The maximum relative error between the calculated values and the measured values in the literature of average crack spacing is 11.17%,the average ratio of the calculated maximum crack width to the measured values and the measured values in the literature is 1.02 and 1.01 respectively,and the coefficient of variation is 0.05 and 0.12 respectively,indicating that the proposed formula can accurately calculate the maximum crack width of reinforced UHPC beams.

关 键 词：超高性能混凝土(UHPC) 最大裂缝宽度 半理论半经验法 应变不均匀系数 平均裂缝间距 四点抗弯试验 

分 类 号：TU375.1[建筑科学—结构工程]