基于 Timoshenko 梁理论和能量变分原理，对单箱单室混凝土薄壁箱梁的翘曲位 移函数进行修正，合理构造考虑各翼板翘曲位移函数幅值关系、横截面轴力平衡以及剪切 变形影响的翘曲位移函数，建立了体系总势能函数表达式． 利用 Euler-Lagrange 方程得到 了薄壁箱梁剪力滞效应计算理论的微分方程，推导了考虑剪力滞效应影响的简支梁挠度 计算公式． 结合 ABAQUS 有限元数值模型算例，对比分析了简支梁在不同荷载工况下挠 度沿梁轴向的分布规律． 结果表明:针对不同荷载工况下的单箱单室薄壁简支箱梁，文中 提出的挠度计算公式的结果与 ABAQUS 有限元数值吻合较好． 同时选取目前工程应用较 为广泛的一般梁挠度简化计算方法进行对比分析． 由于此类简化计算方法忽略了剪力滞 效应存在而产生的附加挠度，导致误差较大，最高达到 32． 06%，误差范围为 21． 39% ～ 32． 06%． 文中所提出的挠度计算方法的结果与有限元数值模拟的结果吻合良好，能较好 地反映结构在外荷载作用下的变形规律，且不受加载工况影响，从而验证了文中挠度计算 方法的正确性及适用性． 

Based on the Timoshenko beam theory and the energy-variation principle，this article makes some corrections to the warping displacement function of thin-walled single-cellbox girder considering the warping displacement amplitude difference between different flanges，axial force equilibrium condition across section，and the shear deformation effects of webs on warping displacement function and the expression of total potential energy is built． Euler-Lagrange equation is used when the structure under the stable equilibrium state，and the differential equation of deflection in simply supported beam is deduced． Combined with the finite element method ( FEM) software ABAQUS，the beam deflection distribution along the length of the beam has been analyzed． The results show that the deflection distribution calculated by the theoretical analysis in this article is consistent with those obtained from FEM analysis． Meanwhile，a widely used deflection formula for engineering application is introduced for analyzing the deflection of simply supported beam． On account of neglecting the shear lag affect，which can generate the additional deflection，this widely used formula can have big errors by comparing the results with FEM results，up to 32. 06%，the error range can be 21. 39% ～32. 06%． However，the deflection distribution along the length of the beam in this article is in a good agreement with FEM results，which can better reflect the actual beam deflection under different loads． Consequently，the proposed method has been validated to be accurate and feasible．