In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden.

在混凝土箱梁中，必须考虑腹板中钢筋的数量和分布，钢筋应考虑偏心外部荷载和横截面变形引起的局部影响，而不仅仅是纵向分析的合力引起的整体影响：扭转和弯曲。这项工作提出了一个分析模型，使设计人员可以考虑所有这些全局和局部效应的相互作用来确定钢筋。该模型基于应力场理论，并已与3D有限元分析进行比较，以验证相互作用域。结果表明，与更完善的3D分析相一致，但减轻了计算负担，所提出的分析模型如何轻松，可靠地进行加固评估。