Subsurface pipeline construction and rehabilitation company Trenchless Technologies won the International Society for Trenchless Technology’s (ISTT’s) 2012 No-Dig Award for its work on a sewerage rehabilitation project in Port Elizabeth.
Phase 1 of the project was valued at R3.5-million and Phase 2 at R11.5-million.
The company undertook the rehabilitation of two parallel sewers in Port Elizabeth’s business district, beneath Govan Mbeki avenue. Phase 1 of the project was completed in 2007 and Phase 2 in 2011.
The first sewer measured 450 mm in diameter and increased to 525 mm pipe further down the line. The second measured 900 mm, increasing to 1 050 mm pipe further down. There was also a 200 mm sewer that needed work.
“Rehabilitation on 560 m of the 450 mm sewer and 570 m of the 900 mm sewer was undertaken in Phase 1 of the project. In Phase 2, rehabilitation was carried out on 600 m of the 525 mm sewer and 720 m of the 1050 mm sewer.
“The length of 200 mm sewer replaced measured 16 m,” says Trenchless Technologies MD Sam Efrat.
The rehabilitation project was originally designed using the spiral wound technique, but the Trenchless Technologies team soon discovered that site conditions required the incorporation of other techniques in certain locations, such as cured-in-place pipe (CIPP) and pipe bursting (a trenchless method of replacing buried pipelines without the need for a traditional construction trench by pushing the replacement pipe through the old pipe using a bursting head).
“The project involved five different trench-less techniques, including spiral wound