The three cable-stayed bridges on the Wele River in Oyala were completed in 2014. These signature bridges will become a new emblematic entrance to the new city of Oyala developed by the Government of Equatorial Guinea. The bridges have been designed to have a clear identity without disturbing the natural environment. Because of the difficult access to the site, the minimization of material quantities has been a major feature to reduce the construction cost.
The three bridges share similar characteristics. They are all 135 m long, with a main span of 80 m. The deck of each bridge, 22.6 m wide, accommodate six vehicular traffic lanes, a central median and two pedestrian walkways. Each deck is a composite steel-concrete structure supported by two cable planes, and it consists of two 1.4 m deep prestressed concrete girders, which are supported by stays spaced at 6.7 m. The two stay-cable planes are connected to four pylon legs, forming an H-shaped pylon with open legs at the top. Each mast has a total height of approximately 27 m, with 21 m above the deck.
Construction of the central span used balanced cantilever method to reduce impact on the river. During the entire bridge construction process, Pedelta provided construction engineering services. The actual stay forces and precambers were continuously updated to take into account actual site measurements of material properties as well as duration of the erection stages. The first bridge was completed by the end of 2011, the second in 2012, and the third in the mid-2014.
Sobrino J.A.; Two Cable Stayed Bridges in Oyala (Eq. Guinea). International Bridge Conference. Pittsburgh (USA), June 2012.
Sobrino, J.A.; Oil Refining Industry adds more roads, bridges to Guinea Landscape. pp. 20-24. Roads & Bridges, October 2012.