Composite Truss Bridges: new trends, design and research

Developments and new trends in composite truss bridges are reviewed, and recent designs are presented for road and railway bridges. The structural scheme may range from a continuous truss girder to a cable-stayed bridge with a double deck for both road and rail traffic.
Composite decks with 3D tubular triangular trusses for road bridges are discussed; design issues are outlined and some results for the elastoplastic redistribution of internal forces at ULS, based on recent numerical and experimental research studies, are presented.
Recent designs of skew semi-through composite trusses, for High Speed Railway, are reported in what concerns the dynamic behaviour under traffic loading and the stability of the compressed chord. The Base Case Design of a cable-stayed bridge, 540 m long main span, with a double composite truss deck, for the new railroad crossing of the Tagus River in Lisbon, is discussed.