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Project Description
New Bridge 15 is part of the new south access road to Guatemala City. The bridge is necessary for the road to span the Pinula River, in the municipality of Villa Canales.
Bridge 15 is designed with a composite deck made up of steel girders and a top concrete slab. It has an overall length of 161 m, divided into three remarkably uneven spans, with lengths of: 51+50+60 m. The bridge is entirely curved in plan, with a curvature radius of 148 m and a constant longitudinal slope of 3.2%, uphill from abutment 1 to 2. The cross-section has a superelevation of 7.6%.
The roadway will accommodate four lanes (2+2), separated by a New Jersey type barrier (0.60 m), plus two traffic barriers of 0.35 m width on the sides, for a total deck width of 17.96 m.
The superstructure consists of a composite deck of 3340 mm constant depth, composed of six girders of 3000 mm depth topped by a reinforced concrete slab of 275 mm thickness, slightly raised above the girders. The girders are spaced 3200 mm between them and have 979 mm long overhangs. Support and intermediate diaphragms and bracings are provided on the upper sliding plane.
Design/Construction Approach
The incremental launching method was chosen due to the lack of accessibility for equipment and material to the riverbed (a seasonal river) and the availability of space at one of the abutments (future toll plaza). Besides the complete design of the deck under service and seismic conditions, Pedelta also designed the temporary elements for the launching operations. These included the launching nose and tail, the jack auxiliary beams, the temporary foundations of the supports in the assembly yard, the diaphragms and braces for lifting and bearing replacement operations, among others.
The strong in-plan curvature of the bridge along with the necessary precamber of the steel structure cause certain areas of the deck to come off the rollers during several launching stages and make the distribution of reactions on these temporary bearings and the deck itself difficult to estimate. To accurately obtain these reactions, we made a three-dimensional nonlinear model of the type “composite” (bar elements for top and bottom flanges and shell elements for the webs).
