Rehabilitation of the Figueira da Foz Bridge

The Figueira da Foz Bridge over the river Mondego in Portugal consists of a 405m cable-stayed bridge and two approach viaducts. It was built in 1982. The pylons include four hollow concrete inclined legs. The stays are made of galvanised wires and the bridge deck is a steel construction. The deck of the approach viaduct is made of concrete. An assessment of the safety of the structure showed that the structures had suffered significant deterioration and that seismic strengthening was required. For the cable-stayed bridge, the main modifications were strengthening of the transverse top beam of the towers by adding an external prestressing system, and replacing and strengthening the anchorage system of the deck to the transition piers. General rehabilitation and a new corrosion protection system for the steel elements were required. For the approach viaducts, the main modifications were the strengthening of the main girders, the introduction of earthquake damping devices and general rehabilitation of concrete structures. Details are given of the rehabilitation and strengthening processes.