摘要
粘结滑移有限元分析是掌握型钢混凝土托换梁变形特性的关键手段.采用有限元分析软件建立了考虑和不考虑型钢与混凝土粘结滑移两种有限元模型,分析了托换梁荷载-挠度曲线、型钢应变及箍筋应变的变化规律.结果表明:不考虑粘结滑移时,托换梁的极限荷载、跨中挠度与试验值差值百分比范围分别为 1.0%～6.8%和 11.3%～24.5%,受剪段中部、梁跨中位置的腹板应变和内、外侧箍筋应变与试验值的差值百分比分别为23.1%、46.4%、15.8%和45.8%;考虑粘结滑移后,托换梁的极限荷载、跨中挠度与试验值差值百分比范围分别为0.7%～4.5%和5.7%～18.2%,受剪段中部、梁跨中位置的腹板应变和内、外侧箍筋应变与试验值的差值百分比分别为2.7%、1.3%、11.6%和27.7%;考虑型钢与混凝土粘结滑移的有限元模型可更准确地模拟梁的承载力和变形.
Abstract
Finite element analysis of the bond-slip between section steel and concrete is a critical approach to understanding the deformation characteristics of steel-reinforced concrete underpinning beams.Two finite element models are established using finite element software:one considers the bond-slip constitutive relationship between section steel and concrete,while the other does not.The paper analyzes the load-deflection curve,strain of section steel,and stirrup strain.The results indicate that,without considering bond-slip,the underpinning beam exhibits an ultimate strength capacity and mid-span deflection difference with the test results in the percentage range of 1.0%to 6.8%and 11.3%to 24.5%,respectively.The percentage differences for the web strain in the middle of the shear section,web strain in the middle of the beam span,inner stirrup strain,and outer stirrup strain concerning test values are 23.1%,46.4%,15.8%,and 45.8%,respectively.When the bond-slip is taken into account,the underpinning beam's ultimate strength capacity and mid-span deflection difference with the test results fall within the percentage range of 0.7%to 4.5%and 5.7%to 18.2%,respectively.The differences for the web strain in the middle of the shear section,web strain in the middle of the beam span,inner stirrup strain,and outer stirrup strain concerning test values are 2.7%,1.3%,11.6%,and 27.7%,respectively.Therefore,the infinite element model considering the bond-slip between section steel and concrete provides a more accurate simulation of bearing capacity and deformation.
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