Consorcio Devisab started the construction of a new road bridge over the Magdalena River between Flandes and Girardot. The main river crossing is cast-in-place concrete box girder with an overall length of 300 m and three spans of 75, 150 and 75 m. The 107 m west approach is a three-span bridge with precast concrete I-girders of equal length of 35 m.
The main bridge is built in balanced cantilever. This erection method reduces environmental impact to the Magdalena River and does not required heavy construction equipment, resulting in a safe and rapid construction. The deck is very wide – 23 m – and it consists of a post-tensioned concrete single cell box, whose depth varies between 3 m at mid span and 8.4 m at piers.The platform accommodates four 3.65 m wide road traffic lanes, a central median, and two 1.8 m lateral shoulders and sidewalks on both sides. The deck is a tapered post tensioned concrete single box cell with inclined webs. The two piers in the riverbanks are relatively short, with height of either 11.50 m or 14.40 m. Accordingly, the piers take the form of two parallel reinforced concrete walls to provide flexibility to the structure, mitigating the demands due to imposed deformations.
Compared to a single rectangular shaft, this design brings many benefits, including optimization of footing, significant reduction in cost, and improvement against imposed deformations and seismic demands. At abutment 1 and at pier 3, which divides the bridge in two parts, an post-tensioned system prevents the bearings from uplift in case of a seismic event.
The completion of the bridge is expected in summer 2018.