One of New Zealand’s leading pipeline services companies, JB Contractors specialises in sewer, stormwater and water mains. Family owned and operated, the company is managed by two directors, Paul and Mark Balemi – sons of Jack Balemi who, in 1952, established the JB group.
Since 1986, JB Contractors has developed extensive expertise in Trenchless Technology, and has introduced several trenchless techniques to New Zealand.
The company has successfully installed and renovated many kilometres of underground pipelines without open excavations for authorities and clients throughout New Zealand.
Recently, the Franklin District Council contracted JB Contractors to replace an existing 300 mm NB RC pipeline at Tuakau, south of Auckland, with a significantly larger diameter pipe to reduce the risk of accidental sewage overflow into the nearby creek during heavy rain. The contract involved the replacement of 200 metres of the old concrete sewer line with a line of 450 mm OD HDPE pipe.Article continues below…
There were significant challenges. The only route was to follow the existing line – up to 4.5 metres deep – across four privately owned properties and under a family home. The bypass pumping had to operate during construction and existing manholes had to be replaced.
The residents and the council, whose Senior Engineer was Atish Chandra, were concerned about the stability of homes being adversely affected by underground work and vibrations. Other concerns included properties being turned into an unsightly work site complete with smell, noise and mud, not to mention the potential costs should the house be damaged. It potentially had all the hallmarks of a nightmare job unless managed professionally.
JB Contractors used Trenchless Technology to provide an excellent, long-lasting asset for the council with minimum disruption and risk to residents. There was no damage to the house and no significant complaints were received by the council.
JB Contractor’s Gigant pipe bursting system – one of very few operating in New Zealand – made ‘mincemeat’ of the old pipe. A constant tension produced by a DD6 drill guided the tool through the old pipe, and burst the existing pipe with an impact of up to 300 tonnes. An expander displaced remaining fragments into the surrounding soil and the new pipe was pulled in behind the bursting tool.
It required minimal excavation and reinstatement. Apart from service connections, only two excavations – 1 metre x 3metre – were required.
The pipe installation was completed in two consecutive days, much faster and cleaner than using other excavation or pipe jacking methods.
Pipe bursting can be used where open-cut methods are not practicable, and where pipes are structurally unsound and leaking, or liable to fail.
JB Contractors Managing Director Paul Balemi says the company’s experienced and skilled staff are always key to the company’s success on contracts.
“Some have been with us for more than 20 years. They deliver innovative, cost effective answers to our contracts. We keep our staff up-to-date on new technology and developments to make sure that we always deliver best practice to our clients’ challenging projects.”
As well as using the pipe bursting method, JB Contractors also specialises in directional drilling, horizontal drilling, microtunnelling, pipe reaming, pipe ramming, cement mortar lining and sliplining, and provides technical advice for authorities and organisations tackling complex projects.