Award of Merit: Transportation Category
Structural Reinforcement for Centenario Bridge with Near-Surface-Mounted CFRP
Submitted by Ingelab, Chile
Ministerio De Obras Publicas
Providencia-Santiago de Chile
Centenario Bridge is part of a ring-shaped highway called “Circunvalación Américo Vespucio,” located in Santiago, Chile. Its traffic is about 75,000 vehicles per day. The reason for the reinforcement was to increase the capacity of the structure, from three to four tracks per direction, by transforming the space corresponding to pedestrian sidewalks in new tracks for vehicles, considering the structural deficit that was necessary to cover due to the new configuration of loads.
The study concluded the need to strengthen the entire floor from the board in the beginning of the cantilever end where bending moments on the top were not fully covered by the existing concrete frame. These applications, supported by the design procedures of ACI 440.2R-02, determined the amount of carbon fiber needed to be distributed along the bridge and in the solutions at the ends of the floor, where diagonal connecting joints produced acute and obtuse angles on the board.
The solution was implementing a concrete fiber-reinforced polymer (CFRP) near-surface-mounted system, in which reinforcements are installed and grooves are made from 0.8 to 1.6 in. (20 to 40 mm) in depth in the concrete, and then the 0.6 x 0.08 in. (16 x 2 mm) section CFRP bars are immersed in an epoxy adhesive. At the extremes of the bridge floor, a special configuration was provided that included the use of carbon fiber wrap as a complement to CFRP bars.
The advantage of applying this technology was that the entire bridge reinforcement, which took 60 days, did not interrupt traffic, minimizing inconvenience. Beyond the benefit of rehabilitating the original structure without damaging the original structural concrete, work was efficient with low contamination.