无腹筋UHPC梁抗剪性能的尺寸效应研究  

ANALYSIS OF SHEAR PERFORMANCE AND SIZE EFFECT OF UHPC BEAM WITHOUT STIRRUPS

作　　者：唐滔 龙再志 修维 彭德坤 蒋明辉 TANG tao;LONG Zai-zhi;XIU Wei;PENG De-kun;JIANG Ming-hui(China MCC5 Group Corp.Ltd,Chengdu,Sichuan 610000,China;Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]中国五冶集团有限公司,四川成都610000 [2]北京工业大学材料与制造学部,北京100124

出　　处：《工程力学》2025年第5期184-196,共13页Engineering Mechanics

摘　　要：该文为了研究无腹筋UHPC梁抗剪性能的尺寸效应,设计了6根无腹筋UHPC试验梁,其剪跨比为2,梁截面有效高度为150 mm~490 mm,并考虑了钢纤维掺量对梁抗剪性能的影响。通过分析试验现象、荷载-挠度曲线、试验梁抗剪作用下混凝土曲线拱的压应变,梁的延性与挠跨比,从而探讨了无腹筋UHPC梁抗剪性能的尺寸效应机理。结果表明:无腹筋UHPC梁的抗剪性能存在尺寸效应,尺寸越大的梁其名义极限剪应力越小;随着试验梁尺寸的增加,梁的变形能力逐渐减小,刚度与脆性增加,钢纤维的桥联作减弱。该文考虑了混凝土拱体在梁抗剪作用下的尺寸效应,推导了无腹筋UHPC梁的抗剪承载力模型,模型计算值与试验值吻合性良好,变异性小。In order to study the size effect of shear performance of UHPC beams without Stirrups,designed were six UHPC test beams without Stirrups,with a span ratio of 2 and effective section height of 150 mm~490 mm.The influence of steel fiber content on the shear performance of the beam was considered.By analyzing the test phenomena,load-deflection curves,and compressive strain of concrete curved arches under the shear action of test beams,ductility and deflection-span ratio of beams,discussed was the size effect mechanism of shear performance of UHPC beam without Stirrups.The results show that there is a size effect on the shear resistance of UHPC beams without Stirrups,and that the larger the size of the beam,the smaller the nominal ultimate shear stress.With the increase of the test beam size,the deformation capacity of the beam gradually decreases,the stiffness and brittleness increase,and the bridge connection of steel fiber weakens.In this study,considering the size effect of concrete arches under the shear action of beams,the shear bearing capacity model of UHPC beam without Stirrups is derived,and the calculated values of the model are in a good agreement with the test values with little variability.

关 键 词：UHPC梁 名义极限剪应力 尺寸效应 混凝土拱体 钢纤维掺量 

分 类 号：TU375.1[建筑科学—结构工程]