Esorfranki is on track to significantly exceed its pipejacking targets for 2011. Water&Sanitation Africa took the opportunity to find out about some of the company’s pipejacking projects.

The company has recently completed a R19 million pipejacking project for WBHO on the Secunda to Sasolburg pipeline, during which it deployed eight pipejacking teams on the project to carry out 1 200 mm and 1 800 mm pipejacks under 23 roads and railway lines.

According to Anton Naude, Esorfranki’s pipejacking manager, “Esorfranki has been party to every southern African pipejacking record set to date and has contributed extensively to bringing the viability of the technique to the civil engineering fraternity in southern Africa. Our expertise in this field dates back to 1978 and includes water supply, railway crossings, gas pipeline and bridge jacking projects across South Africa and neighbouring African countries.”

Pipejacking is also carried out beneath rivers and Naude says the company has just been awarded a R2.5 million contract by Johannesburg Water to conduct 60 metres of jacking underneath the Jukskei River at a depth of about 12 metres.

Concrete pipejacking
Concrete pipejacking methods use a steel shield with a hydraulic jack that is positioned at the front of the pipeline. In unstable ground conditions, the jacked structure may be installed as a sleeve through which the actual service will later pass or within which an in-situ invert may be constructed. A single sleeve pipe may be used to install a variety of smaller services.

The company is currently conducting concrete pipejacking in Gaborone, Botswana, where it is close to completing a R20 million jacking project for a sewer reticulation upgrade for civil contractor, China Jiangsu International. Naude says this project has been carried out under very difficult conditions, with a high water table and hard rock encountered underground. The jacking sites for the 1 800 mm sewer pipes with a two metre diameter are located across the city centre, allowing limited working space to sink the jacking pits.

At OR Tambo International Airport, a culvert jacking project 450 mm beneath the tar road has recently been completed. The concrete culvert is seven metres wide by three metres high and 17 metres long, and was commissioned to serve as a pedestrian walkway to and from the Gautrain station.

As a sub-contractor to Stefanutti Stocks, Esorfranki is working on a R7.7 million contract at the Medupi Power Station to jack 1 800 mm pipes through solid rock. Also at Medupi, the company is conducting a R7.9 million pipejacking project for Civcon, involving two pipejacks 1 860 metres in length.

Other current contracts include a pipe culvert at Lynwood Road for the City of Tshwane Metropolitan Municipality and a culvert at Potchefstroom University for pedestrians and vehicles.

“Our jacking team has decades of experience in all kinds of challenging conditions, with a proud track record of successful projects over more than 30 years. The team, which includes a surveyor, is complemented by a full range of jacking equipment. At any given time, we are able to have 23 pipejacks out in the field. Uniquely, we also have our own four-man in-house blasting team, making us the only company in South Africa able to conduct blasting, surveying and pipejacking using in-house capabilities,” says Naude.

Fact box
What is pipejacking?
Pipejacking is a specialist technique used to install underground pipelines and culverts with minimal disruption to property, traffic or services on the surface. Pipes and culverts are progressively advanced through the ground using high performance hydraulic jacks. Material at the head of the pipeline or culvert is excavated to the exact profile of the structure prior to jacking. This material is removed to the jacking pit via the structure being jacked, where it is hoisted and tipped. Pipejacking is used for sewers and storm water drains, gas and water mains, electricity and telephone cables, box culverts and subways.