Modeling of curved composite I-girder bridges using spatial systems of beam elements

A new way of modeling steel composite bridges has been presented by Vayas et al. (in press, 2010) 3. and 4.. The proposed model is based on the representation of steel I-girders by equivalent trusses. The concrete slab is suitably represented by a set of bar elements, and the bearings by appropriate springs. Diaphragms and stiffeners may also be taken into account. In comparison to the grillage model, which is usually used for the analysis of bridges, the proposed three-dimensional model allows a more reliable prediction of deformations, internal forces, and stresses. Curved bridges display unique behavior characteristics, and for this reason a grillage analysis is not always suitable. The new way of modeling composite bridges, using a spatial system of beam-like structural elements, is applied in this paper for the modeling of curved composite bridges. Worked examples are provided to illustrate the set-up procedure of the proposed modeling and to compare its results with those of corresponding finite element models.

Research highlights
► Three-dimensional modeling of composite bridges, I-girder represented by a truss (Fig. 1 and Fig. 2).
► Coupled torsion and bending in curved bridges.
► Stress analysis in erection phase (Fig. 10).
► Stability analysis, comparison with finite element models (Fig. 11).