New Road Bridge at Oxec II Dam

Project Description

Located in Central Guatemala, the new Oxec Bridge is just upstream of the Oxec II dam, which was completed in 2018. The new structure was necessary to replace the existing bridge, which is now submerged since the completion of the dam.

The bridge is composed of three spans of lengths: 49.5+77+49.5 m for a total length of 176 m from abutment to abutment axis. It is straight in plan with a constant longitudinal slope of 1%. The structure was designed and checked to be incrementally launched from one of its ends.  The deck consists of three continuous steel I-girders of a constant 3.2 m depth. The spacing between girders is also constant, at 3.4 m. Lateral overhangs add 1.4 m in width on both sides of the deck, which is completed by a 32.5 cm thick concrete slab. The total deck width of 9.60 m can accommodate two traffic lanes, lateral shoulders, and steel traffic barriers. The piers are 32 m in height with a rectangular voided section of 2 x 6.8 m with 50 cm thick walls. They are supported on 11.4 cm diameter steel micropiles.

Design/Construction Approach

The incremental launching method was chosen because the steep slopes of the site made equipment access difficult thus girder erection with cranes was ruled out. In addition to the design of the bridge, Pedelta carried out the design of the temporary elements for the launching operations such as a tapered launching nose, lateral guides and diaphragms for the jacking operations for replacement of temporary bearings, among others. Concrete haunches were used to compensate for girder deflection uncertainty.