Handbook of International Bridge Engineering
Herry Vaza2013, Handbook of International Bridge Engineering
The project includes a cable-stayed bridge and two approach viaducts: one on the Chaco side on National Route 16 and another one on the Corrientes side on National Route 12 (Figure 3.22). Those structures are 2000 m long (1666 m over water) and 8.3 m wide, with one lane in each direction. The vertical navigation clearance is 35 m. The required horizontal clearance is 200 m. The cable-stayed bridge comprises three spans (163 m + 245 m + 163 m). It is composed of two 225 m long suspended structures, placed symmetrically along the main pylons axes, which are 245 m apart. A simply supported span of 20 m links these two structures to form the main span of 245 m. This suspended span reduces the effect of deflections on the two main structures. Each main pylon is a W-shaped frame that rests on a pile cap for its foundation. A set of eight stays completes each main 83 m high pylon. The cross section is a two-box girder. The deck is completed with precast transverse slabs, 6.9 m long and 2 m wide, supported on the main beams. When the deck was finished, the transverse beams were prestressed. The original stays were of the locked coil type, but they had to be replaced after 25 years of service. The longitudinal beams of 3.5 m deep were prestressed. The approach viaducts over the river are composed of nine spans of 82.6 m each on the Chaco side, and three spans of 82.6 m each on the Corrientes side. They were built by the balanced cantilever method with precast segments 4.1 m long and 2 m deep at center span and 4.5 m deep over the supports. The overall deck width is 11.3 m, carrying two 3.65 m wide lanes, narrow emergency shoulders of 0.50 m and pedestrian sidewalks 1.5 m wide. The piers of the approach viaducts are constant deep box sections and were built by the sliding formwork method. The foundations were made using 1.8 m diameter bored piles with variable lengths between 38 m and 60 m, and with preloading cells, they are clamped by penetration into the hard clay stratum. At around 20 years of service, the replacement of all the stays was required. Construction works were carried out by Freyssinet SA (Spain) in 1995. Parallel strands stays were installed. The link between both cities, with only two lanes, has proven to be insufficient for the traffic, which has been ever-growing since its construction. The construction of a new bridge is now under consideration. Construction work began in August of 1968 by the initiative of the governments of the provinces involved: Corrientes, Chaco, and Formosa. The owner was DNV, who called for international bids in 1965.
