Senqu Bridge in Lesotho: engineering innovation to overcome Drakensberg mountain and water challenges

The Senqu Bridge is the first extensioned bridge in Lesotho, a type of structure that combines elements of both cable-stayed bridges and beam bridges. This design solution was identified to ensure high resistance to gusts coming from the Drakensberg Mountains and, together with a pre-stressed concrete deck, allows for overcoming the limitations of an area that, until the start of construction, appeared difficult to access.

The bridge consists of 16 continuous spans that follow the profile of the valley up to the 100-metre central span,

 The work is strategically linked to the future Polihali dam.

The planned reservoir would, in fact, have rendered major sections of the A1 road axis impassable, isolating Mokhotlong and several mountain villages.

When the Lhwp programme is completed, 'Lesotho will be able to benefit from new energy capacity and revenue from the water supply to South Africa, while South Africa will be able to count on an additional water transfer to the Gauteng industrial region, contributing to the water security of one of the most economically important areas of the country'.

"Webuild has a historical presence in the Lesotho Highlands Water Project programme, to which it has also contributed with the construction of some of the major infrastructure, including theKatse Dam, one of the tallest arch dams in Africa, and the Mohale Dam, as well as tunnels and related hydraulic works.

Globally, the Group has built 1,023 km of bridges and viaducts in more than 300 major road, motorway and railway projects, including the Genoa San Giorgio Bridge, built in record time, the Second Bosphorus Bridge in Turkey, and the Sydney Metro Northwest skytrain bridge, a curved, cable-stayed structure, crowning the four-kilometre viaduct also built by the Group as part of the first phase of development of the Sydney Metro.