Key services
- Engineering – complete engineering services, feasibility, preliminary and detail final design reports, principal design and technical specification.
- Procurement – preparation of procurement package including conceptual design, technical specification, commercial terms and conditions, tender evaluation and adjudication report.
- Detailed design – approval of contractors' detail designs, supervision of construction, erection and commissioning
- Project and construction management.
Key facts
- The project comprised the design outline and implementation of a 400kV single circuit guyed tower transmission line
- The African Development Bank (ADB) provided financing for the project
- The project capital cost was £14.2 million
- The project duration was 36 months
Challenges
- The project required the design of towers to be fit for purpose, yet cost-effective
- Crossing of obstacles such as rivers, major roads and railway lines
- Poor and varying ground conditions through the Kalahari Desert made it difficult to achieve the required tower footing earth resistances.
Solutions
- Economical approach to the design of towers by type testing the design parameters at an accredited testing centre in India
- Large spans were used to cross large obstacles such as the Mahalapye River. The line route section was designed to be as direct as possible between terminals, while minimising the environmental and sociological impact on affected communities.
- Special earthing using deep copper electrodes buried in conducting cement allowed the required tower footing earth resistances across the Kalahari Desert.
Value and benefits
- Our experience provided an economically advantageous line design with a suite of towers to meet the project objectives.