基于MCFT理论的PC空心板梁抗剪强度分析  

An Analysis on Shear Strength of PC Hollow Beam Based on MCFT Theory

作　　者：武建 赵国浩 张峰[2] 张璐珂 WU Jian;ZHAO Guo-hao;ZHANG Feng;ZHANG Lu-ke(China Design Group Co.,Ltd.,Nanjing Jiangsu 210000,China;Geotechnical and Structural Engineering Research Center of Shandong University,Jinan,Shandong 250061,China)

机构地区：[1]华设设计集团股份有限公司,江苏南京210000 [2]山东大学岩土与结构工程研究中心,山东济南250061

出　　处：《公路交通科技》2024年第2期126-138,共13页Journal of Highway and Transportation Research and Development

基　　金：山东省自然科学基金项目(ZR202102260046,ZR202102240664)。

摘　　要：为研究预应力混凝土空心板梁的抗剪强度,基于6次预应力混凝土空心板梁抗剪强度试验,对板梁斜裂缝扩展、极限抗剪强度开展分析,基于修正斜压场理论(MCFT),建立了板梁理论计算模型,研究了预应力混凝土空心板梁箍筋间距的等效间距法确定原则,对比试验数据,验证了其有效性并分析弯剪组合效应对抗剪强度的影响,针对预应力、配筋率、钢筋和混凝土强度等不同参数开展分析。结果表明:加载点位置抗剪强度计算值与试验抗剪强度的比值为0.71,剪跨中点位置抗剪强度计算值与试验抗剪强度的比值为0.99,支座位置纯剪状态下抗剪强度计算值与试验抗剪强度的比值为1.11,考虑弯矩后,板梁抗剪强度削弱,剪跨中点位置计算值与试验值更为接近;预应力混凝土空心板梁在弯剪组合状态下,全黏结预应力钢筋数量由2根提高到10根,抗剪强度提高21.7%;随预应力筋数量的增多,有效预应力大小对抗剪强度的影响更为显著,当弯矩为100 kN·m时,有效预应力由186 MPa增加到1395 MPa的过程中,2根预应力筋抗剪强度提高10.2%,6根预应力筋抗剪强度提高15.3%,10根预应力筋抗剪强度提高20.3%。In order to study the shear strength of prestressed concrete hollow beams,based on the tests on shear strength of prestressed concrete hollow beams carried out for 6 times,the crack development and ultimate shear strength of slab beam are analyzed.The equivalent spacing method is proposed to determine the stirrup spacing of prestressed concrete hollow slab beams.The theoretical calculation model for slab and beam is established with modified compression field theory(MCFT),and the validity of the models is verified by comparing with the test results.A lot of parameter analysis is carried out to study the influence of concrete strength,steel strength and other parameters on shear strength of inclined section.The result shows that(1)the ratio between the calculated shear strength at the loading point and the test shear strength is 0.71,the ratio between the calculated shear strength at the midpoint of the shear span and the test shear strength is 0.99,and the ratio between the calculated shear strength and the test shear strength at the support position in the pure shear state is 1.11;(2)the number of fully bonded prestressed reinforcement increases from 2 to 10,and the shear strength of prestressed concrete hollow slab beams increases by 21.7% under the bending and shearing;(3)with the increase of the number of prestressed tendons,the effect of the effective prestress size on the shear strength is more significant,when the bending moment is 100 kN·m,the shear strength of 2 prestressed tendons and 6 prestressed tendons increase by 10.2% and 15.3% respectively,when the effective prestress increases from 186 to 1395 MPa,the shear strength of ten prestressed tendons increases by 20.3%.

关 键 词：桥梁工程 抗剪强度 MCFT理论 预应力混凝土空心板梁 弯剪组合 

分 类 号：U443.35[建筑科学—桥梁与隧道工程]