Upstand Finite Element Analysis of Slab Bridges

For slab bridge decks with wide transverse edge cantilevers, the plane grillage analogy is shown to be an inaccurate method of linear elastic analysis due to variations in the vertical position of the neutral axis. The upstand grillage analogy is also shown to give inaccurate results, this time due to inappropriate modelling of in-plane distortions. An alternative method, known as upstand finite element analysis, is proposed which is sufficiently simple to be used on an everyday basis in the design office. The method is shown to give much better agreement than the others when compared with an elaborate three-dimensional solid finite element model. Single- and two-span bridge decks with solid and voided sections are considered for both longitudinal and transverse bending stresses.