Los Lagos Region, Chile
The construction of the Chacao Bridge aims at connecting the continent with Chiloé Island, located 1.100km south of Santiago de Chile, in the Los Lagos Region, 48km away from Puerto Montt and only 5km away from Pargua.
In 2012 and 2013, the project was consolidated through the traditional fiscalpublic construction system, with the creation of an international bid registration. In December 2013, the contract was awarded to the Consorcio Puente Chacao (Chacao Bridge Joint Venture), an entity formed by four international companies headed by the Korean Hyundai.
Three years later, the design of the Chacao Bridge was recognized with the “Be Inspired” award in the category “Bridges Innovations,” which consolidated these MOP Roads Direction’s initiative as an “avant-garde” project worldwide.
Route 5 is the longest highway in Chile, stretching from Arica to Quellón in Chiloé, hence connecting the country throughout a 3353 km long highway. However, when reaching the end, the road is interrupted between the continent and Chiloé Island by the Chacao Channel, where all traffic runs, via a 30 to 45 minutes ferry trip. The bridge under construction will connect the missing part, expediting the main transportation to/from Quellón at the southern tip of Chiloé. Once the project has been completed, there will be no interruption between the continent and Chiloé Island. The country will be permanently connected from Arica in the north of Chile to Quellón in Chiloé Island, through Route 5, which will be extended for 190 km. The bridge will cut the time required to cross the channel to just three minutes. This is a major improvement considering the actual trip time of about 30 to 45 minutes that the ferry takes to cross the channel, without taking into account the extreme weather conditions the channel faces throughout the seasons.
The length of the bridge will be 2,574 m and will consist of three main pylons, one in the middle of the channel and two on each side, namely the North Pylon on the continent side and the South Pylon on the Chiloé’ Island’s. The span between the Central and North Pylons will stretch for 1,155 m, while the ones between the Central and South Pylons will cover a 1,055 m length, thus becoming the longest suspension bridge in South America.
Trevi Chile SpA (Trevi), was selected by the consortium to carry out the foundation works of the bridge piles, including the Central Pylon (already completed), as well as the North and South Pylons, currently under construction. The foundation works of the Central Pylon consisted in the execution of 36 piles with 2.5 m wide diameters and lengths of 54 m for type one piles and 58 m for types 2 and 3 approximately, each of them excavated from a jack-up barge.
Ocean currents were among the challenges Trevi had to face during the execution of the Central Pylon. They were about 528 cm/s on the marine surface and 192 cm/s on the sea bottom, caused by the ebb and flow of tidal streams. Moreover, weather
conditions were harsh, with strong winds ranging between 18 and 23 m/s (65-83 km/h), an average temperature of 11°C and torrential rains throughout the year, with an average precipitation of 2000 mm per year.
Notwithstanding the above, the main technical challenge Trevi had to overcome was the size of the piles, along with the length, diameter and weight of the permanent steel casings and the reinforcement cages, which involved the use of heavy machinery in the limited space available on the jack-up barge. Therefore, logistics and project management as a whole were undoubtedly another great challenge. In addition to the casing installation, drilling works and concrete casting on the Central
Pylon, Trevi was in charge of the assembly of the reinforcement cages and the welding of steel casings.
The works carried out for the Central Pylon were the following:
36 piles with a 2500 mm width diameter and a 54m or 58 m length.
Total volume of concrete cast on piles: 10,713 m3
Steel rebar used for the reinforcement cages: 2,256 t
Steel used for the steel casings: 3,447 t, and 24 m, 28 m length.
Trevi S.p.A. 5819, Via Dismano 47023 Cesena Italy | Phone +39.0547.319311 Fax +39.0547.319313