ABSTRACT
The city of Valdivia is located in the Los Rìos Region, in southern Chile, crossed by several rivers, among which is the navigable Cau Cau river, which divides Isla Teja from the Las Ánimas sector. The Ministry of Public Works tendered the design and construction of the Cau Cau Bridge, which provides a new road alternative to access both the city and the coast of the region and allows the passage of boats, including towards the city shipyard. The awarded proposal consists of three structures: a 110-meter-long northern access viaduct, the main bascule bridge, 165 meters in total and a 70-meter main span, and the 88-meter southern access viaduct. The Cau Cau Bridge is the first mobile structure built in Chile. On February 24, 2015, during the startup stage of the construction phase, and while the lifting operation of the decks is being carried out, one of the hydraulic lifting devices in the southern sector fails, finally generating that the bridge was not opened to service. This paper provides the forensic engineering study carried out by the principal after the failure produced in one of the deck leaves, with a critical analysis of the management protocol carried out, the hypotheses of the causes, analysis of the manufacturing process, assembly and construction process of the deck, study of the oleo hydraulic and mechanical systems and the modeling of the structural system, in order to determine the origin of the failure. The conclusions of the investigation and the lessons learned for the process of design and construction of singular bridges in Chile and their application in other projects are delivered.
