Influence of Structural Bracing on Stability and Torsional Resistance of Truss Footbridges

Structures composed of lattice beam subassemblies are commonly used for constructing pedestrian bridges with medium spans. These structures are typically equipped with wind bracing at the top. Another scenario where lattice walls are employed is in box girders with concrete decks. During the installation phase, these girders are fitted with upper flange bracing to ensure overall structural stability. For composite decks or those with orthotropic steel plating, lattice bracing may also be arranged at the bottom. Truss walls can be transformed into plate beams using the transformed beam method, which simplifies efficiency analysis, particularly for torsional stresses. This case study presents an example of equating a truss structure with a plate structure under torsional loading. The efficiency of closed sections compared to open sections for pure torsional resistance is analysed.