预应力混凝土空心板梁抗剪试验及剪切斜裂缝评估研究  

Study on Shear Test and Evaluation of Shear Diagonal Cracks for PC Hollow Slab Beams

作　　者：罗文林 王成明 顾冠男 刘其伟[3] 于心然[4] LUO Wen-lin;WANG Cheng-ming;GU Guan-nan;LIU Qi-wei;YU Xin-ran(Nanjing Brgtec Engineering Technology Co.,Ltd.,Nanjing Jiangsu 211102,China;Shaoxing Housing and Urban-rural Development Bureau,Shaoxing Zhejiang 312099,China;School of Transportation,Southeast University,Nanjing Jiangsu 211102,China;Jiangsu Nanjing-Suqian-Xuzhou Expressway Co.,Ltd.,Suqian Jiangsu 223814,China)

机构地区：[1]南京博瑞吉工程技术有限公司,江苏南京211102 [2]绍兴市住房和城乡建设局,浙江绍兴312099 [3]东南大学交通学院,江苏南京211102 [4]江苏宁宿徐高速公路有限公司,江苏宿迁223814

出　　处：《公路交通科技》2023年第6期148-154,共7页Journal of Highway and Transportation Research and Development

摘　　要：为了及时发现在役预应力混凝土空心板梁梁端腹板斜裂缝,评估其开裂后的剩余抗剪承载能力,做好预防性养护措施,以跨径16 m的预应力混凝土空心板梁为研究对象,进行了梁抗剪承载能力足尺试验研究。设计了3组不同剪跨比的试验工况,利用千斤顶加载至预应力混凝土空心板梁彻底失去抗剪承载能力,研究了梁体裂缝发展过程、裂缝分布特征、裂缝宽度、钢筋应变发展过程、开裂荷载、极限荷载等力学响应及试验现象,得到了梁端腹板斜裂缝、底板横向裂缝、剩余抗剪承载能力的对应关系。通过观测梁端底板横向裂缝特征,即可推断出梁端腹板是否存在斜裂缝以及斜裂缝的特征。结果表明:先张法预应力混凝土空心板梁受剪破坏具有一定的脆性特征,斜裂缝的出现和发展较为突然,斜裂缝附近的箍筋应变在裂缝出现后骤增,甚至箍筋直接屈服;剪跨比对空心板梁的破坏模式和抗剪承载力有着显著影响,剪跨比最大和最小的试验梁分别具有一定的斜拉和斜压特征,剪跨比越大的试验梁极限抗剪承载力和开裂承载力越小。将抗剪极限破坏试验中裂缝特征与结构受剪损伤程度之间建立了联系,对梁端腹板因为抗剪不足导致的斜裂缝病害进行了损伤评级,提出了评定预应力混凝土空心板梁梁端腹板斜裂缝病害的方法,可以用来指导在役预应力混凝土空心板梁抗剪裂缝的处治。In order to promptly detect the diagonal cracks on the webs of PC hollow slab beam ends,assess the residual shear bearing capacity after cracking,and implement preventive maintenance measures,taking a 16-meter span PC hollow slab beam for the research object,a full-scale experimental study on the shear bearing capacity of the beams is conducted.Under the 3 sets of designed different shear-span ratios for the test conditions,the PC hollow slab beams are loaded by using jack to completely lose the shear bearing capacity,the mechanical responses and experimental phenomena such as crack development process,crack distribution characteristics,crack width,steel strain development process,cracking load,ultimate load of the beam are studied,the correspondences of the diagonal cracks on the webs of the beam ends and the transverse cracks on the bottom plate with the residual shear bearing capacity are obtained.By observing the characteristics of transverse cracks on the bottom plates of the beam ends,it is possible to infer the presence and characteristics of diagonal cracks on the webs.The result shows that(1)The PC hollow slab beams subjected to shear failure using the pre-stressing method exhibits certain brittle characteristics.The appearance and development of the diagonal cracks are relatively sudden,and the strain of the hoop reinforcement near the cracks increases sharply after crack initiation,even leading to direct yielding of the hoop reinforcement.(2)The shear-span ratio significantly influences the failure mode and shear bearing capacity of the hollow slab beams.The test beams with the highest and lowest shear-span ratios have certain characteristics of diagonal tension and compression respectively.The higher the shear-span ratio,the smaller the ultimate shear and cracking bearing capacity of the test beams.The connection between the crack characteristics and the degree of structural shear damage in the ultimate shear failure test is established,the damage rating on the diagonal crack disease caused by insuffi

关 键 词：桥梁工程 病害评估 足尺试验 空心板梁 腹板斜裂缝 抗剪破坏 

分 类 号：U448.21[建筑科学—桥梁与隧道工程]