配有斜筋混凝土梁抗剪承载力计算与试验  

Shear capacity and experiment of reinforced concrete beam with diagonal reinforcements

作　　者：张建仁[1] 刘彬[1] 王磊[1] 张旭辉[1] 

机构地区：[1]长沙理工大学桥梁工程安全控制省部共建教育部重点实验室,长沙410004

出　　处：《应用力学学报》2012年第6期746-751,779,共6页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(50878031)

摘　　要：以剪压破坏时配有斜筋的混凝土梁为研究对象,考虑临界斜裂缝处各钢筋拉应力和剪应力的影响,基于极限平衡理论和复合应力状态下混凝土的强度准则,建立了极限抗剪承载力的计算公式。对配有斜筋混凝土梁进行的试验研究发现,理论值与试验值的误差不超过5%。研究表明:箍筋与纵筋、斜筋与纵筋的相对配筋率以及剪跨比对临界斜裂缝顶端混凝土受压区的高度影响较为显著,进而影响抗剪承载力;临界斜裂缝顶端混凝土在复合应力状态下发生破坏,竖向压应力的作用不应忽略;斜筋和箍筋的剪应力对极限抗剪承载力影响较小,计算中可不予考虑。Experimental investigations for the failure of reinforced concrete beams with diagonal reinforcements under shear and compressive condition have been carried out.An analytical model for the calculation of the ultimate shear capacity is proposed by using the limit equilibrium theory and the strength criterion of concrete material under the multiaxial stress state.In this model,the effects of tensile and shear stresses of steel rebar on the critical diagonal crack are taken into account.Experimental investigations for reinforced concrete beams with diagonal reinforcements indicate that the error is not exceed 5% between the theoretical results and the experimental ones.Results obtained show that the shear-span ratio and the relative rate of stirrup and diagonal reinforcement with longitudinal reinforcement have significant influences on the depth of compressive zone ahead of the critical diagonal crack,and then have great influence on the ultimate shear capacity of beams.The concrete ahead of the critical diagonal crack is crushed under the multiaxial stress state and the effect of vertical compressive stress can not be neglected.The diagonal reinforcement and stirrup have little influence on the ultimate shear capacity and then can be omitted in computational estimation.

关 键 词：桥梁工程 钢筋混凝土梁 斜筋 剪压破坏 极限抗剪承载力 

分 类 号：U447[建筑科学—桥梁与隧道工程]