The design of the new road between Aguaclara and Cúcuta, located in the Santander province of the Andes region of Colombia, included the design of multiple bridges. Due to the complex topography of the site and the magnitude of the valleys, composite decks consisting of a concrete slab on steel I-girders have been proposed.
Six of these bridges were designed by Pedelta. They consisted of continuous span bridges with typical span lengths of about 40 m. In all six cases, due to the existing limiting factors, the metallic structure of the deck has been conceived to start from one edge of the bridge. Temporary shoring towers will be built after building the entire metallic structure of the deck.
The bridges were designed according to AASHTO LRFD. Applicable seismic design specifications as well as specifications related to the incremental launching construction method (applicable to the launching of the metallic structure of the deck) were also considered. A detailed 3D model of the deck, which included the effect of the concrete slab and the intermediate and support diaphragms as well as the construction phase, was developed.
In order to increase the efficiency of the resistant mechanisms of the bridges against seismic loading, seismic isolators were provided between the superstructure and substructure of the bridges. The use of such devices increased the fundamental period of the structures in the horizontal directions and thus reduced (considerably) the seismic loads to be considered for the design of their substructures.