May 2015, Vol. 70, No.5


Volvo Pipelayer Supports Swedish Water Pipeline

At Huddinge, seven miles south of the country’s capital, the Stockholm Water Company is building a new water pipeline.

The region covers the central part of the Södertörn peninsula and more than half consists of agriculture, forests, hills and lakes, as well as seven nature reserves.

Stockholm Water owns and maintains nearly 3.3 miles of water and sewer systems in Stockholm, producing 360,000 m³ of drinking water every day to meet the demands of the city’s 1.3 million residents. The company also treats and purifies wastewater before releasing it into the Baltic Sea, protecting the aquatic environment.

For this latest project, the utility provider has contracted Stuttgart based Ed. Züblin to handle and lay the pipeline. Founded in 1898, Züblin has branches in several European countries and ranks among the largest construction and civil engineering contractors in Germany.

Heavy lifting

To assist with the heavy lifting, Züblin has rented a Volvo Construction Equipment (Volvo CE) PL3005D pipelayer – the first one to be used in Sweden. Its 51-ton tipping capacity enables it to handle the 16-meter long 48-inch pipes with ease. Each concrete coated steel pipe weighs 11 tons, and a total of 75 pipes will be required to complete the 1,200 meters (1.3 miles) of pipe needed for the project.

“With the weight of pipe and lift block totaling around 12 tons, the PL3005D was as steady as a rock,” says Martin Karlsson, Züblin’s site manager. There are 20 people working on the site and other machines being used include Volvo crawler excavator models EC240CLR, EC250DL and EC55.”

A two-meter (79-inch) boom extension attachment gives the PL3005D a higher hook height, which, considering the size of the pipes and the height of the truck, facilitates lifting and stacking. Once lifted, the rotating upper structure of the pipelayer allows the machine to smoothly position the pipes where required. The boom extension can be conveniently hinged back and locked into position on the boom, to avoid dismantling it from the machine.

“It was a little different to operate but I got the hang of it pretty quickly,” says operator Olle Pettersson, with 35 years of experience operating excavator machines. Although designed for pipelaying, the PL3005D is built based on Volvo’s standard EC300D excavator, but with a heavier undercarriage, making it a straight forward transition for operators.

The PL3005D was also used to hold the pipes in position for welding. Similar to truck unloading operations, the hydraulically elevating cab provides excellent operator visibility.

Semi trenchless construction

On this project, the trench is a three- to four-meter (118-157 inch) deep tunnel and the pipe will be pushed through it using hydraulic rams. Using a system known as Pipe Express, no groundwater lowering is necessary and in comparison with the open trench construction method, the route can be up to 70 percent narrower, so earthworks are considerably reduced for a low environmental impact. The tunnel is created by a tunnel boring machine (TBM), also known as a mole. The TBM loosens the soil, which, using a milling machine vertically connected to it, is then conveyed directly above ground. It is then pulled along using a remote controlled vehicle.

The ground, comprised mainly of clay, is soft and is constantly moving, so nine meter (354 inch) sheet piles hold it in place. The PL3005D was also used for this operation, with a separate pile driving hammer held in the hook.

“The pile driving operation was a lot more comfortable as less vibrations come through the machine,” says Pettersson. “Given the length of the piles, the boom extension providing extra height, was also an advantage in this application.”

The project was scheduled for completion in April.

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