Installation of two Brandenburger Liner DN 700 in difficult terrain

Difficult to access shafts in wooded areas and the conduit of large amounts of water were the challenges faced in February 2008 by Umwelttechnik und Wasserbau GmbH during a big pipe lining project in Michelstadt in the Odenwald. In a first construction section, two Brandenburger GFRP liners DN 700 were installed at a length of about 160 metres each. A significant advantage for the successful completion in high quality proved to be the handling of the BLUETEC^® light curing technology and the quick curing.

The unusually large project was commissioned by the Abwasserverband Mittlere Mümling in Michelstadt. The project includes the construction-free installation of five inliners with a total length of 1100 metres in municipal storm sewers DN 400 to DN 1000 at a depth of up to 5.20 metres. Additionally, the corresponding robot jobs, including TV inspection and technical soundings, need to be carried out. The damage images show significant damages to parts of the old pipe by tree root intrusions, cracks and broken fragments.

Economical implementation thanks to BLUETEC^® UVA light-curing process

The competitive contract was awarded to Umwelttechnik und Wasserbau GmbH (U&W). Jürgen Schäfer from the U&W subsidiary in Frankfurt: “We won the contract not the least because we were able to submit an inexpensive offer based on the quick execution with our Brandenburger BLUETEC® system. Working with the Brandenburger curing technology using UVA light goes relatively quick in comparison to other methods. This makes it not only cheaper, but more advantageous for the client, because the whole construction project is accomplished much quicker and thereby minimises many negative side-effects of a construction site.” Thus also in Michelstadt: The affected sewer sections are feed collection drains to a sewage treatment plant. Relatively a lot of water flows through these large sewers. The construction and the preparations for the water drainage to drain the pipes completely is a significant time and cost factor in such a case. The briefer the water needs to be held back, the less complicated and the less costly the project becomes.

GFRP liners ADV 95 were installed with a wall thickness of 7 millimetres

The two liners DN 700 that U&W installed as a first construction section were 162 and 158 meters long respectively. GFRP liners of the type ADV 95 were used with a wall thickness of 7 millimetres. Some of the shafts were in a business zone and others were in a woods that was difficult to access. Schäfer reports on the perils of these local conditions: “The liners had already been delivered at the end of 2007, ready-for-installation by Brandenburger. Due to the inconvenient weather conditions, the ground in the woods was rather soggy and the shafts were even more difficult for us to access. That is why we temporarily stored the liners onsite on the property of the company.” It was an advantage thereby that the factory-impregnated pipe liner could be stored so well. Packed UV-proof in stable boxes, storage is possible for many months without the material suffering any damage or reacts.

A challenge for the handling: Each liner weighed tremendous 6.5 tonnes

To transport the crates with the large liners safely to the respective installation sites, the U&W employees employed wheel-type loaders with heavy hoists that could be rented locally on short notice. Each of the saturated pipe liners weighed tremendous 6.5 tonnes after all. These colossuses are pulled in by a winch that is employed as standard equipment by U&W. The insertion is done at one go in an installation process through 3 conduits with an average drawing speed of 1 metre per minute. The advantages of the Brandenburger UVA light technology procedure proved beneficiary in regards to the handling on-site. “The location in the woods did not make it easy to bring in the equipment,” said Schäfer. “Before we switched to the Brandenburger technology involving light-curing resins, we did a lot with warm-water curing. Especially in such dimensions as in this case and in rough terrain, the bringing in of the water and the technical equipment that I need to heat that water is a real problem. There's none of that with light-curing liners. And since the liner is delivered pre-saturated and ready-for-installation, there is no need for handling chemicals such as resins and curing agents on site.”

The hardening speed was between 30 and 70 cm/m

Once the liners had been drawn in from shaft to shaft into the damaged pipe by the winch, the rehabilitation specialists from U&M applied special packers down in the shafts at both liner ends with which the liners were sealed. After the liner that was thus sealed was erected by compressed air and pressed, form-fit against the old pipe's wall, the mobile UVA light unit was employed. By employing the procedure developed by Brandenburger, the curing process can be controlled in detail: The entire process is controlled electronically and monitored using TV cameras. The curing itself proceeds quite quickly; for the project in Michelstadt, the curing speed was between 30 and 70 cm per minute. Each inversion took just one day - including the corresponding measures for water drainage and the necessary completion and milling work.

Clients were impressed by the completion in high quality

“We were one of the first users of the new BLUETEC^® light-curing technology,” Schäfer explained. “One and a half years ago, we bought what was the prototype from Brandenburger and have always been working with it by standard ever since. We have really had excellent experience with this procedure. The essential advantages are surely the much quicker curing times and the highly convenient operation.” Also in Michelstadt, the execution of the first construction section took place without a hitch. All nominal values have been reached. “There was a great approval by the client who was truly impressed by the high-quality execution.” The further measures that still need to be completed are planned for May 2008.

Contact and additional information
Umwelttechnik und Wasserbau GmbH
Subsidiary Frankfurt/Main
Ferdinand-Porsche-Straße 9a
60386 Frankfurt/Main, Germany
Telephone: +49 (0) 69 - 42 01 18 - 10
Telefax: +49 (0) 69 - 42 01 18 - 19
http://umwelttechnik-wasserbau.de
E-mail: frankfurt-m - at - umwelttechnik-wasserbau.de

>> Hungary