Metolong Dam Pedestrian Bridge

JG Afrika

Fulton Award: 2015 Best Civil Engineering Structure with a value up to R100 million
CESA Aon Award: 2014 Best International Project
SAICE Award: 2013-2014 Technical Award for Structural Engineering
SAICE Award: 2013 -2014 Best International Project (Pmb Branch)

Client: Metolong Authority
Project team: Lowlands Waterworks Joint Venture comprising JG Afrika, RHDHV and GWC
Contractor: EXR Construction
Sub-Contractor: Structural Systems Africa

The Metolong Dam Pedestrian Bridge provides a vital link between communities divided by the tail waters of the new Metolong Dam built in Lesotho. The design presented a challenge in so far as a cost-effective solution had to be found for a fairly long bridge, with a relatively lightweight deck, to span a deep and steep-sided gorge. Of the alternatives considered, a prestressed concrete ribbon bridge seemed the most ideally suited for the task, particularly in an area where hard and massive sandstone is available for anchoring the bridge abutments.

The bridge deck is continuous over two spans with respective lengths of 102 m and 127,5 m. The total walkway length, including the approaches over the abutments is 249 m. The central support of the bridge consists of a 35 m tall reinforced concrete pier, seated on top of a sandstone cliff 15 m above the river bed.

JG Afrika, as part of the Lowlands Waterworks Joint Venture, designed the bridge for the Employer, Metolong Authority. The design is innovative, cost-effective, aesthetically pleasing, highly functional and environmentally friendly as it does not have towers, stabilisers or large abutments that would impose on the rural landscape. Most importantly, it perfectly met the needs of both the client and the community.