摘要
为研究无粘结预应力无腹筋UHPC梁的剪切力学行为,设计了1片矩形截面UHPC梁并进行了剪切试验。试验采用1000 t电液伺服长柱压力试验机对试验梁进行了单点加载,测试了UHPC梁的挠度、梁腹位置主应变、加载点截面正应变和钢绞线应力增量等数据,并将抗剪承载力试验结果与法国标准和瑞士标准UHPC梁抗剪承载力计算结果进行对比。结果表明:在剪跨比λ适中时(λ=1.86),无粘结预应力无腹筋UHPC梁发生剪压破坏;由于UHPC中钢纤维的桥接作用,试验梁在斜裂缝出现以后并未立即失去承载能力,仍然可以承受继续增大的荷载;试验梁在发生破坏时加载点下方截面底缘混凝土拉应变达到2700με,表明UHPC材料具有较好的抗变形能力;现有法国标准和瑞士标准对于UHPC梁抗剪承载力的计算方法均偏保守,未能考虑剪跨比和纵向钢筋消栓作用对抗剪承载力的影响。
This study focuses on the shear performance of the unbonded prestressed UHPC girder without web reinforcement.A UHPC girder specimen of rectangular cross-section was prepared for shear tests.The specimen was loaded at a single point by using the 1000 t electro-hydraulic servo-controlled compression testing machine.The data concerning the deflection of the UHPC girder,the principal strain in the girder soffit,normal strain in the cross-section at the loading point,and the stress increments of steel strands were obtained.The test results were compared with the shear bearing capacities of UHPC calculated by using the formulas given in the French standard NF P 18-710 and Swiss standard SIA 2052 UHPFRC.It is concluded that at a moderate shear-span length ratio(λ=1.86),the unbonded prestressed UHPC girder without web reinforcement succumbed to shear compression failure.Due to the bridging effect of steel fibers in the UHPC,the specimen did not lose load bearing capacity immediately when oblique cracks occurred,and was still able to accommodate the increasingly intensified loads.When the specimen failed,the tensile strain of the bottom-edge concrete in the cross-section under the loading point reached 2700με,indicating that the UHPC material has sound deformation resistance.The shear performance of UHPC girder calculation methods given in the French and Swiss standards are conservative,since the shear-span ratio and the dowel action of the longitudinal reinforcement are not counted.
作者
刘志峰
卢涛
包杰
王祥雨
黄相又
LIU Zhifeng;LU Tao;BAO Jie;WANG Xiangyu;HUANG Xiangyou(Poly Changda Engineering Co.,Ltd.,Guangzhou 510030,China;Sichuan Provincial Transportation Engineering Quality Supervision Station,Chengdu 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《世界桥梁》
北大核心
2024年第5期69-75,共7页
World Bridges
基金
四川省科技计划资助项目(2020YJ0081)。
