Chacao Bridge.

Channel, Chile

The Chacao Bridge links the island of Chiloé with mainland Chile crossing the Chacao Channel. When opened to traffic, the Chacao Bridge will be one of the longest suspension bridges in the world with three-tower and double main suspension spans of 1,155m and 1,055m, and two side spans of 324m and 216m. The bridge is located in one of the most active seismic zones in the world. The bridge deck is made of a 25.8m wide orthotropic deck, which will carry a total of four (4) roadway traffic lanes.

BTC Scope:

• Design of Main Suspension Cables: BTC provided innovative design for the main suspension cables with prefabricated parallel wire strands (PPWS) strands to accommodate lifting capacity and transportation facilities between the Port and bridge site.

• Design of Main Suspension Cable Connection at Center Tower: When the two main suspension spans are subjected to unsymmetrical loads, the horizontal forces of main cables on two sides of the middle pylon saddle are different, leading to relative slipping. When the unbalanced cable force exceeds the static frictional force between the saddle and the main cable, the relative slippage will occur between the main cable and the saddle, and such occurrence renders the structural system unbalanced. BTC provided a unique design solution for the main suspension cables to eliminate slippage at the center tower.

• Design of Central Saddle: BTC provided and developed a unique central saddle design to accommodate the main suspension cable connection at central saddle.

• Design of Hanger Cables: BTC provided parallel wires strand (PWS) hanger design with cast iron steel sockets.