THE ALAMILLO CABLE-STAYED BRIDGE: SPECIAL ISSUES FACED IN THE ANALYSIS AND CONSTRUCTION

The Alamillo bridge is one of the long-span bridges crossing the Guadalquivir river built on the occasion of Expo '92 held in 1992 in Sevilla (Spain). The bridge is a cable-stayed structure spanning 220 m without any intermediate supports, and its originality is in the lack of back stays and the balancing of the front stays through the backward inclination of a massive pylon. Although the bridge has a steel deck, the pylon is a composite element, with an external steel formwork structurally connected to the filling concrete. This paper deals with the main problems faced and the experiences acquired during the analysis, design and construction processes of this bridge. The uniqueness of such a structure lies in sophisticated and complex design and construction stages, complemented by accurate monitoring of the real forces (in deck, pylon and stays) and movement during the construction achieved by using a huge and impressive amount of instrumentation. (A)