Exploration of super-large-span prestressed steel truss-concrete composite continuous rigid frame bridges

To succeed to major advantages while overcome demerits of the existing prestressed concrete (PC) continuous rigid frame bridge, a new type of prestressed steel truss-concrete composite continuous rigid frame bridge (PTCB) is put forward in this paper. The PTCB is schemed with a composite main beam combining steel truss with concrete prestressed in batches to fully exert the respective superiorities of shape steel, prestress tendons and high-strength concrete, which can greatly cut down the superstructure self weight and in turn enable a slimmer substructure shape compared with the PC correspondents. Therefore, the PTCB is especially suitable for design of super-large-span continuous rigid frame bridges. A preliminary analysis of a rigid frame bridge with a 400m span indicates: a PTCB design could effectively simplify the construction process, save the building time and result in a bridge structure with more concise mechanics and more reliable performances. In addition, the PTCB could basically avoid the latent distresses of uncontrollable long-term main- beam deflection and concrete cracking that often haunt the PC continuous rigid frame bridges.