以附加挠度为广义位移的双室箱梁剪力滞效应研究

Study on shear-lag effect of twin-cell box girder with additional deflection as generalized displacement

从剪力滞翘曲正应力自平衡条件出发,引入修正系数对翘曲位移函数进一步修正,选取剪力滞效应引起的附加挠度为广义位移,将箱梁的剪力滞变形状态从初等梁挠曲变形状态中分离出来作为一种独立的变形状态分析,应用能量变分法建立箱梁截面控制微分方程,结合简支边界条件分别给出集中荷载和均布荷载作用下箱梁附加挠度和初等梁挠度的解析解。数值算例表明,初等梁挠度解和材料力学初等梁挠度解、跨中截面测点本文应力解和文献有限元解均吻合良好,证明将剪力滞纵向翘曲模式与初等梁竖向挠曲模式分离的假设是正确的。挠度研究表明,剪力滞效应对均布和集中荷载跨中挠度分别提高了3.17%和3.73%。

Based on the axial force equilibrium condition,a correction factor was introduced to further modify the warping displacement function.Shear-lag effect is caused by the additional deflection as the generalized displacement,shear lag deformation conditions are separated from the deflection condition of the primary beam as an independent deformation conditions and construction with the energy variation method for the section control differential equation of box girder,and the boundary condition was unified to solve the analytical solution of additional deflection and deflection of primary beam under concentrated load and uniform load.The numerical examples demonstrate that the deflection solution of the primary beam in this paper shows a good agreement with the material mechanics,and the stress solutions of this paper show a good agreement with the paper solutions,and prove the assumption is correct,i.e.,the longitudinal shear lag effect is separated from the primary beam.Study on the deflection shows that the shear lag effect increased by 3.17%and 3.73%respectively under the uniform load and concentrated load.