Chacao Channel Bridge

 

A virtual view of Chacao Bridge, Chile

 

If you are planning to visit Chile in the near future, you might be interested in one of the most ambitious and impressive engineering projects in the country: the Chacao Bridge. This bridge, which will connect the island of Chiloé with the mainland, crossing the Chacao Channel, will be the longest suspension bridge in South America and one of the most earthquake-resistant bridges in the world.

The Chacao Bridge project was conceived as a way to celebrate Chile's bicentennial in 2010, but it has faced many challenges and delays since then. The original design was modified several times to adapt to the complex geological and environmental conditions of the site, which is located near a seismic fault zone where a record-shattering 9.5 magnitude earthquake struck in 1960. The construction also suffered from financial and contractual issues, leading to changes in the consortium responsible for the works. The current consortium, formed by Hyundai Engineering & Construction and Systra, took over the project in 2015.

As of December 2023, the bridge has a 44% progress, which is behind schedule. The expected completion date has been postponed several times, and the latest estimate is November 2026. The initial cost of the project was estimated at US$740 million, although it is projected that the final amount will be higher.

Main Features of the Bridge

                                                                                                  

Despite these difficulties, the Chacao Bridge promises to be a remarkable feat of engineering and a symbol of Chile's development and integration. The bridge will have a total length of 2.75 km, with three spans of 1.1 km, 1.2 km and 0.45 km. It will have four lanes for vehicular traffic and two lanes for pedestrians and cyclists. It will be supported by two main towers of 160 meters high each, and four secondary towers of 80 meters high each. The bridge will use more than 23,000 tons of steel and 68,000 cubic meters of concrete.

The bridge will also incorporate innovative features to withstand earthquakes and strong winds. It will have a seismic isolation system that will allow it to move up to 2 meters horizontally and 0.8 meters vertically during a quake. It will also have a wind tunnel system that will reduce the aerodynamic forces on the deck and cables. The bridge will be able to resist winds of up to 250 km/h, earthquakes of up to 9.0 magnitude and strong sea currents.

The submarine mountain known as Roca Remolino (Whirlpool Rock), in the middle of the channel, will play a preponderant role in the construction of the Megaproject. Its resistance has proved to be the most propitious place to place the central pillar of the viaduct. Without the rock formation, it would probably not have been possible to undertake the construction due to the high cost that it would have represented. Its name, Remolino, is precisely due to the current produced there with the change of the tides. In ancient times, this underwater massif caused many shipwrecks and deaths.

The Chacao Bridge will bring many benefits to the region and the country. It will reduce the travel time between Chiloé and the mainland from 40-30 minutes by ferry to only 3 minutes by car. It will also boost tourism, trade, connectivity and cultural exchange between the island and the rest of Chile. It will create more than 4,000 jobs during its construction and operation. It is estimated that the lifetime of the bridge will be around 100 years.

The Chacao Bridge is a project that reflects Chile's vision and ambition to overcome natural and human-made obstacles and to connect its diverse and beautiful territory. It is a bridge that will not only link two shores, but also two worlds: the modern and the ancestral, the urban and the rural, the continental and the insular.