The Chacao Channel Bridge, also known as the Chiloé Bicentennial Bridge, is a suspension bridge currently under construction to link Chiloé Island with mainland Chile across the Chacao Channel. First proposed in the 1960s and repeatedly delayed, revived, and cancelled over the following decades, the project was one of several intended to commemorate Chile's bicentennial in 2010. Construction of the current design began in 2017. When completed, it will be the largest suspension bridge in South America and Latin America. The opening of the bridge is planned for the second half of 2028.https://elinsular.cl/noticias/chiloe/2024/06/28/mop-confirmo-terminacion-del-puente-chacao-para-el-segundo-semestre-del-2028/
The bridge will replace the ferry service that has long connected the village of Chacao on Chiloé Island with the village of Pargua on the mainland, and its construction has been the subject of decades of political and social debate over its cost, benefits, and environmental and cultural impact on the archipelago.
History
Origins (1960s–1973) By the late 1950s, Castro had scheduled air service to Puerto Montt, Santiago, and Coyhaique, but steamship service remained the primary means of travel to and from the archipelago, and the road network within Chiloé Island itself was minimal, with only a few paved stretches near Ancud, Castro, and Quellón. A regular bus service between Puerto Montt and Ancud, requiring passengers to cross the channel by boat, began operating in late 1958 as the Pan-American Highway was extended toward Pargua.
After the 1960 Valdivia earthquake destroyed much of the island's port infrastructure and its underused railway, the government of Jorge Alessandri prioritized improving Chiloé's land connectivity, and the first roll-on/roll-off ferry began operating across the channel in 1964.
In the mid-1960s, local congressman Félix Garay became the first to propose a bridge linking Pargua and Chacao, inspired by San Francisco's Golden Gate Bridge and estimated at the time to cost US$80 million; he presented the idea to the governments of Eduardo Frei Montalva and later Salvador Allende. In 1967, Garay and other congressmen introduced a bill to incorporate the Chacao Channel crossing into the national highway planning, financing, and construction system; the bill became law in 1972, but the proposal was shelved after the 1973 Chilean coup d'état, when the military government instead prioritized development of the Carretera Austral.
Bicentennial Bridge project (1990s–2006) The idea was revived in the 1990s under President Eduardo Frei Ruiz-Tagle, with preliminary and feasibility studies commissioned during his term. The project gained momentum under his successor, Ricardo Lagos: in 2000 the feasibility of using Roca Remolino as a central platform was confirmed, and by 2001 construction—then estimated at US$300 million—had been confirmed to proceed.
Renamed the "Chiloé Bicentennial Bridge" to mark the Bicentennial of Chile, the project as designed in the early 2000s would have made it, by total length, the third-longest suspension bridge in the world after Japan's Akashi Kaikyō Bridge and Denmark's Great Belt Bridge, and the longest in Latin America, a region dominated by cable-stayed bridges. The design was approved by Chile's National Environmental Commission in late 2002, and a 30-year design-build-finance-operate-maintain tender opened in 2004, which was awarded in January 2005 to a consortium of France's Vinci Construction Grand Projets, Germany's Hochtief, the American Bridge Company, and Chilean firms Besalco and Tecsa, at an estimated cost of US$527 million with construction expected to run from 2007 to 2012.
Cancellation (2006) After Michelle Bachelet took office in March 2006, a review of the project found its cost had risen to US$930 million—well above the US$605–607 million ceiling the government had set—prompting Public Works Minister Eduardo Bitrán to cancel the project in July 2006, with the consortium receiving a US$2 million indemnity. The cost increase was attributed to a more than 128 percent rise in steel prices and to seabed conditions that would have required relocating the central pier, lengthening the main span to 1,200 meters.
The cancellation provoked strong local anger; the mayor of Castro publicly displayed a Spanish flag in protest, and congressman Gabriel Ascencio resigned as head of his party's congressional caucus, accusing the minister of never having intended to build the bridge. Interior Minister Belisario Velasco told local mayors that no bridge would be built during that administration. As compensation, the government announced an infrastructure investment plan for the island—known as "Plan Chiloé"—that included upgrades to the airport and the Castro hospital, improved inter-island ferry services, and a divided highway between Chacao and Quellón.
Controversy resurfaced later that year when a report revealed the Ministry of Public Works had internally reduced its own construction cost estimate to US$486 million (about US$670 million including financing)—well below the concessionaire's figure—leading Chiloé's mayors to accuse the government of never intending to build the bridge and Ascencio to accuse the minister of manipulating the numbers. In 2013, former president Lagos described Bachelet's cancellation of the project as a mistake for Chile.
Revival attempts and reactivation (2009–2014) In June 2009, under Minister Sergio Bitar, the Ministry of Public Works floated a redesigned, cheaper cable-stayed bridge instead of a suspension bridge, citing lower steel prices, though the proposal was criticized by former minister Bitran as unworkable and by opposition figures as an election-season maneuver.
Reviving the bridge had been a priority for Sebastián Piñera even before he took office in March 2010, but the 2010 Chile earthquake and its aftermath delayed those plans. Piñera confirmed in his May 2012 annual address to Congress that the bridge would definitely be built. An international bidding process opened in May 2013 with eight prequalified firms, and in December 2013, days before that year's presidential election, the government approved the sole bid received, from an international consortium of Brazilian, Korean, French and Norwegian capital made up of OAS, Hyundai, SYSTRA, and Aas-Jakobsen; the offer, valued at 360.134 billion pesos, fell within the US$740 million ceiling set by the ministry. Chile's Comptroller General approved the contract in February 2014, formally clearing the way for construction, which was then expected to run for 79 months, opening the bridge in 2019.
In 2014, Hyundai Engineering & Construction won the contract for the construction of the Chacao Bridge, commissioned by the Ministry of Public Works of Chile.
Design and features
The Chacao Channel bridge would replace the ferry that connects the village of Chacao, Ancud Commune, on Route 5 (Ruta 5 Sur) at the northern end of Chiloé Island across the Chacao Channel with the village of Pargua, Calbuco Comuna, on the mainland.
The original 2001–2006 design called for a total length of , consisting of three concrete towers (two high towers and one high south tower), two mainspans of and , and a suspended side span of , providing a minimum vertical clearance for navigation of . It was designed with two one-way lanes on each side, a 100-year design life, resistance to winds over , and strong sea currents; contemporary Chilean sources also described a requirement to withstand earthquakes of up to magnitude 10 on the moment magnitude scale.
The current design, finalized in 2017, connects the two shores at the narrowest point of the Chacao Channel——between Punta San Gallán (Ancud) and Punta Coronel (Calbuco). It has a total length of and a width of , with four lanes, a central tower of in height installed on Roca Remolino, and two north and south towers of and in height, respectively; the south tower is the only one not standing in the water. Due to strong winds in the channel, the bridge is designed to withstand gusts of up to ; however, vehicle traffic will be temporarily restricted during high-wind conditions. Crossing the bridge is estimated to take three minutes at a speed of . High-strength concrete and steel will be used, materials common in large-scale projects worldwide and on which several Chilean researchers have already conducted studies and experimental tests to verify mechanical properties.
In addition to the bridge itself, the project includes an operations center southeast of the structure for data analysis and monitoring, which will also house a viewing platform, café, and a museum on the bridge and the History of Chiloé; a smaller building replicating these functions will stand on the north side. Road access was built separately from the bridge contract: the northern approach was completed as part of the concessioned Puerto Montt–Pargua highway, while the southern access was tendered by the Ministry of Public Works in 2013.
In November 2016, Bentley Systems awarded the project its international "Be Inspired" award for the best engineering design in the world.
Once completed, the bridge will be the longest in Latin America, a region where cable-stayed bridges dominate; the current longest suspension bridges in the region are the Angostura Bridge over the Orinoco River in Venezuela, at a total length of and a main span of , followed by the Hercílio Luz Bridge connecting Santa Catarina Island to Florianópolis, Brazil, at in total length with a main span.Histórico da Ponte Hercílio Luz. Deinfra. Governor do Estado de Santa Catarina.
Construction
Final design and delays Engineering studies and revisions requested by the Ministry of Public Works—mainly concerning seismic and wind loading—meant the final design was not delivered until June 2017 and was not definitively approved until December 2018. Because of these changes and delays, the consortium requested a new deadline and an additional US$200 million in August 2018, and the ministry approved an extension that pushed the expected delivery date to 2023.
Separately, Brazilian partner OAS—which held a 49 percent stake—closed its Chilean offices in 2015 amid the Operation Car Wash corruption investigation in Brazil and announced its withdrawal from the project that October, a process that was not finalized until 2019, leaving Hyundai (originally a 50 percent partner) as the sole company responsible for construction.
Start of construction
Construction officially began in February 2018, ahead of final design approval, with the fabrication of the 36 piles that support the bridge's central pier. Ten piles had been installed by December 2018, thirty by July 2019, and all 36 were complete by September 2019.
Work stoppage (2019–2020) On 23 December 2019, Hyundai halted work on the bridge, accusing the Ministry of Public Works of failing to honor prior agreements and of acting in bad faith over compensation for cost overruns. Public Works Minister Alfredo Moreno responded that Hyundai remained obligated to continue the work and characterized the dispute as a difference of opinion over which party should cover roughly 218 billion pesos in additional costs, which the government argued fell to Hyundai. Hyundai maintained that the Chilean state had not offered the legal and commercial guarantees it needed to keep financing the project.
Resumption and progress
In February 2020, President Piñera stated that the bridge would indeed be built, and the ministry acknowledged—after previously denying it—that it had requested additional works from the consortium, agreeing to pay Hyundai a fair share of the extra costs, an arrangement Hyundai ratified within days. Work resumed in the northern section of the bridge by May 2020.