More about the Mvoti River Project

Background

 

The Mvoti River Pipe Bridge Crossing is an important component of the Umgeni Water North Coast Bulk Water Supply Project. The strategic bulk conveyance system between Ballito and KwaDukuza, comprising large diameter steel pipelines, is necessary to ensure security of supply by meeting the present and projected future water demand requirements in the North Coast area of KwaZulu-Natal. The North Coast Bulk Water Pipeline starts from the Avondale Reservoir in Ballito, traverses through and along several housing developments, farms and major roads, and crosses the Umhlali, Etete and Mvoti Rivers until it terminates at the Mvoti Balancing Reservoir in KwaDukuza. The Pipe Bridge crossing is located over the Mvoti River in Groutville, alongside the existing R103 road bridge between Umhlali and Stanger.

Description of Project

The Mvoti River Pipe Bridge Crossing Project comprises a 280 m long, 800 mm diameter steel pipe supported by a 220 m long steel lattice-type bridge, in turn supported on existing abandoned concrete abutments and an existing reinforced concrete central pier which were extended using reinforced concrete. It includes below-ground reinforced concrete anchor walls which contain the forces generated as a result of the transition from the buried to the above-ground pipe installation, pipe thrust walls, and a system of pipe bearings and bridge bearings. Other salient features of the project include a maintenance walkway along the bridge, and allowance for the installation of a second 800 mm diameter pipeline at a later stage.

Project Scope

The scope of the project comprised the following:

  • Supply, fabrication and erection of the double-arched steel bridge structure spanning 220 m across the Mvoti River, supported on the existing old road bridge central pier and abutments
  • Extension of the existing central concrete pier and end abutments by 13.5 m vertically
  • Construction of temporary works, including access roads and working platforms, river diversion and a temporary support for erection of the first bridge span
  • Installation of 220 m of above-ground and 60 m of buried steel pipeline (800 mm nominal diameter)
  • Supply and installation of expansion and contraction pipe bellows
  • Construction of concrete in-situ plinths, anchor walls and thrust blocks on the north and south banks
  • Supply and installation of the bridge bearings, pipe support bearings
  • Sheet piling, dowelling and anchor bolts
  • Air valve installations
  • Cathodic protection requirements
  • Environmental management and rehabilitation.

Spect Industrial’s Role

Materials used are as follow and data sheets are attached: