Chacao bridge

The Chacao suspension bridge, which connects Chiloé Island with mainland Chile by crossing the Chacao Channel, is the longest suspension bridge in Latin America. This project has been launched by the Ministry of Public Work of Chile (MOP) to boost the economical development of the area by facilitating the access to the island.

The Chacao bridge is the world’s longest double suspension bridge with three pylons. The bridge is located near an active fault, and it is designed to resist severe seismic motion.

SYSTRA, along with JV Partner, AAS-Jakobsen, was responsible for the full detailed design of the bridge. SYSTRA led the seismic studies and design, geotechnical engineering, and the design of the steel orthotropic deck, central pylon, suspension cable anchor blocks, and foundations.

The key technical challenges on this project are associated with the geometry of the bridge with two main spans and with the design under the seismic loads and the wind loads. Among others the contract included the determination of basic engineering data such as seismic and wind input data. One of the main challenges was to find an agreement on the design methodology for the concrete pylon under seismic loads as this type of bridge is not covered by the AASHTO code.