摘要
为研究配置630 MPa高强钢筋UHPC梁正常使用阶段裂缝宽度的计算方法,对6根配置630 MPa高强钢筋UHPC梁进行受弯性能试验,分析试验梁裂缝宽度、挠度及钢筋应力变化规律,建立高强钢筋UHPC梁裂缝宽度计算公式。研究结果表明:(1)受拉钢筋屈服前,裂缝宽度的扩展呈线性规律,裂缝数量不断增加;当裂缝宽度为0.34 mm时,受拉钢筋屈服,裂缝数量和间距趋于稳定,表现出较好的延性;(2)破坏时受拉钢筋均已屈服,混凝土达到极限压应变,高强钢筋与UHPC的配合使用可充分发挥两者优良的力学性能;(3)随着UHPC梁的配筋率增大,试件承载力显著提高,正常使用阶段最大裂缝宽度减小,但延性降低,开裂荷载基本不变;(4)基于40组试验数据,对JGJ/T465—2019规范的裂缝宽度计算公式中钢纤维对钢筋钢纤维混凝土构件裂缝宽度影响系数进行修正,建立适用于UHPC梁的裂缝宽度计算公式,修正公式计算值与试验值吻合良好。
In order to study the calculation method of crack width of 630 MPa high-strength reinforced UHPC(Ultra-High Performance Concrete)beams in normal use,six such beams were subjected to bending test.The variation laws of crack width,deflection and reinforcement stress of the test beams were analyzed.Meanwhile,a calculation formula for crack width in high-strength reinforced UHPC beams was established.The results showed that:(1)The expansion of crack width was linear before the yield of tensile reinforcement,however,when the maximum crack width was 0.34 mm,the tensile reinforcement yielded,in addition,the number and spacing of cracks tended to be stable,the UHPC beams showed good ductility.(2)Upon damage,the tensile reinforcement had already yielded,and the concrete had reached its ultimate compressive strain.So,the combination of high-strength reinforcement and UHPC can give full play to their excellent mechanical properties.(3)With the increase of the reinforcement ratio of the UHPC beam,the bearing capacity of the specimen increased significantly.The maximum crack width decreased in the normal use stage,but the ductility decreased as well,while the crack load was basically unchanged.(4)Based on 40 sets of test data,the influence coefficient of steel fiber on the crack width of reinforced steel fiber reinforced concrete members in the crack width calculation formula of(JGJ/T465—2019)specification was modified,and the calculation formula of crack width suitable for UHPC beams was established.The calculated values of the formula agreed well with the test values.
作者
戎贤
杨松
李艳艳
王凤亮
谭冰
RONG Xian;YANG Song;LI Yanyan;WANG Fengliang;TAN Bing(School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China;The Second Construction Limited Company of China Construction Eighth Engineering Division,Jinan 250022,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2023年第5期1084-1091,共8页
Journal of Disaster Prevention and Mitigation Engineering
基金
河北省自然科学基金项目(E2019202064)
河北省重点研发计划项目(22374501D)
河北省建设科技研究项目(2022—2130)资助。
关键词
高强钢筋
超高性能混凝土
受弯性能
裂缝宽度
high-strength steel bar
ultra high performance concrete
flexural behavior
crack width
