Constructing an Extradosed Bridge in a Remote Location

Built to replace the ferry service that crossed the Zambezi River, Kazungula Bridge links the countries of Zambia and Botswana. DYWIDAG supplied stay cable material and assisted in the installation of the extradosed 923m-long-bridge.

Context

To prepare for this build, DYWIDAG completed a full-size test of the Dyna Link Anchor Box. Material supply began in 2017; transport to site was both difficult and time consuming. Once on site, changes to the bridge’s design required additional engineering support and work with Daewoo on technical proposals and solutions.

Scope

  • Fatigue and ultimate load test Dyna Link Anchor Box (2016)

  • Material supply (began in 2017)

  • Cable installation (2018-2020)

Solution

Containers were shipped to Durban in South Africa, and then by truck for another 1,800km through South Africa and Botswana, until arriving in Kazungula in Zambia. Finally, trucks queued in a 6km long line – two weeks of waiting – to board a ferry to cross the Zambezi River. Despite the logistical challenges, DYWIDAG supplied the stressing anchorage DYNA Grip DG-P31/37/55, fixed anchorage DYNA Grip DG-P31/ 37/ 55, recess pipes with bearing plates, anti-vandalism pipes, and HDPE sheathing, in a timely manner.

Our Technical Service did an excellent job supporting the client, was reflected in their feedback:

"For five years DYWIDAG has faithfully delivered top quality products and services to our door in Botswana and Zambia, with exceptional support from the staff, and such impressive efficiency. Rarely has a supplier given us such a complete package in cable related engineering, specific installation equipment and temporary site supervision." Sung Hwan, Choi, Project Manager, Daewoo Engineering & Construction Co. Ltd.

The bridge was dedicated in May 2021.

Going further

Before building the bridge, a custom full-size test of the Dyna Link Anchor Box was performed on a DG-P 37 stay cable with two anchorages and the DYNA Link anchor box. A two million cycle fatigue test with 100 MPa stress range at an upper load of 60% GUTS was completed without any wire fractures. A subsequent tensile test was performed, also without wire fractures, as a cable force corresponding to 95% AUTS was reached.

DYWIDAG provided additional engineering to solve cable-related problems and supplied tools to guarantee that the cables – and its anchorages – could be installed in perfect geometrical conditions despite changes in design.

SupplyInstallationTechnical SupportSupervision

Transport Hub Republic of Botswana and Road Development Agency Republic of Zambia

Daewoo Engineering & Construction Co. Ltd.