高强超高延性混凝土梁弯剪性能理论分析与数值模拟

Theoretical Analysis and Numerical Simulation of Flexural and Shear Behavior for High-strength Engineered Cementitious Composite Beams

摘要:

开展了14根高强超高延性混凝土（high-strength engineered cementitious composite，HS?ECC）梁的四点弯曲试验，研究了混凝土类型、纵筋配筋率和是否配置箍筋三因素对配筋梁弯剪性能的影响。基于平截面假定和材料本构关系，计算了配筋HS?ECC梁的受弯承载力。基于国内外规范，计算了无腹筋HS?ECC梁的受剪承载力。最后，采用Abaqus软件建立了HS?ECC梁的有限元模型。结果表明：有腹筋梁均为受弯破坏，随着纵筋配筋率增大，试件极限荷载和刚度逐渐增大，而延性未显著降低，配筋HS?ECC梁较普通混凝土梁具有更优异的裂缝分散能力和抗弯性能；无腹筋HS?ECC梁的破坏模式随配筋率增大由受弯破坏转变为受剪破坏，梁受剪承载力和刚度增大，但延性逐渐降低；配筋HS?ECC梁受弯承载力的计算结果与试验值吻合较好；HS?ECC梁有限元模型可有效模拟试件的荷载?位移曲线。

Abstract:

Four-point flexural tests were carried out on 14 reinforced high-strength engineered cementitious composite （HS-ECC） beams. The effects of concrete types， reinforcement ratios of longitudinal bars and stirrups on the flexural and shear behaviors of reinforced beams were explored. Then， the bending capacitity of the HS-ECC beams with stirrups was calculated based on the plane-section assumption and material constitutive models， and the shear capacitiy of HS-ECC beams without stirrups was calculated according to the specifications at home and abroad. Finally， the finite element model of HS-ECC beams was established via Abaqus. It is shown that： all the HS-ECC specimens with stirrups are flexural failure； the ultimate flexural load and the stiffness of HS-ECC beams increase with the reinforcement ratio， but the ductility remains stable； HS-ECC beams with stirrups demonstrate superior flexural performance and crack distribution capacity compared with conventional concrete beams； the failure modes of HS-ECC beams without stirrups vary from flexural failure to shear failure with the increasing reinforcement ratio； the higher the reinforcement ratio of HS-ECC beams， the higher the shear capacity and stiffness， while the lower the ductility； calculation results of the bending capacity of the HS-ECC beams are in good agreement with experimental values； the load-displacement curves of the HS-ECC beams are simulated with the finite element model effectively.