Liebherr Piling, Rotary Rigs Put to the Test in Austria
Drilling Rigs Encounter Challenging Geology
Hilti & Jehle GmbH, an Austrian construction company, is utilizing Liebherr equipment for deep foundations projects. A LB 44 rotary drilling rig is helping with the construction of a factory building in the city of Dornbirn. At the end of 2015, Liebherr’s LRB 355 rig celebrated its debut on one of Hilti & Jehle’s jobsites.
The LB 44 is Liebherr’s largest rotary drilling rig and Hilti & Jehle is using it to insert pile foundations for a new production building measuring 203-by-130 meters. The building project is for Julius Blum GmbH, a company that manufactures functional furniture fittings.
At the outset, the auger drilling method was used. However, due to the extent of the excavations, the decision was made to change to full displacement tools. At least 2,988 piles must be inserted at depths of 28 meters and 29 meters for the foundation work in Dornbirn, which started in March. It is expected to be completed in August.
The ground conditions present a special challenge. Although the soil comprises mainly loam and peat, the work is made more difficult through several layers of densely compacted gravel, up to 6 meters thick.
The new LRB 355 is also in operation for Hilti & Jehle. The 105-ton machine with a maximum height of 33.5 meters made its debut last fall on a building site at the exhibition grounds in Dornbirn. Despite its dimensions, the deep foundation machine is said to be easy to transport with mounted leader, slide and ropes.
Due to difficult soil conditions, and in order to avoid any subsidence, a large number of concrete piles in various forms had to be inserted at the jobsite in Dornbirn.
In the past, various types of machinery would have been necessary, but the multi-functional LRB 355 is able to create different types of piles, depending on the requirements and soil conditions.
“With the LRB 355 from Liebherr we have a modern, top-line machine at our disposal. Thanks to its multi-functionality the quality of foundation work is improved and, at the same time, we are more flexible and can work more efficiently,” says Markus Maehr project manager with Hilti & Jehle.
The LRB has a robust undercarriage as well as long crawlers that are designed to offer drillers increased stability. With the help of parallel kinematics, the piling and drilling rig has a large working radius. An additional advantage is the assembly of all winches directly on the leader. It enables a clear view of the main winch from the operator’s cab and ensures the ropes do not move when the leader is adjusted.
The BAT rotary drive is a new working tool with a torque of 450 kNm, which can be individually configured depending on the application. The main advantages of the hydraulic drive, manufactured by Liebherr, include automatic torque regulation, continuous speed optimization and four electronically adjustable speed ranges.
The most recent jobsite for the LRB 355 was in St. Gallen, Switzerland. There it was equipped with the double rotary drive type DBA 300. In combination with a Liebherr concrete pump type THS 80 D, the piling and drilling rig was used to insert 316 piles for a secant pile wall.
The foundation work is for a multi-story office and apartment building. The piles have a diameter of 900 millimeters and lengths of between 18 and 22 meters. Despite challenging soil conditions and remarkable drilling depths the one pile took 1.5 hours to complete.
In addition to drilling with a double rotary drive, the LRB 355 can also be used for other common drilling methods, including Kelly drilling, full displacement drilling or continuous flight auger drilling. Using the Kelly drilling method the LRB 355 achieves its maximum drilling depth of 60 meters. Other applications for which it can used include soil mixing and operation with vibrators and hydraulic hammers.
Liebherr’s product range includes earth-moving and material handling machinery, mining equipment, mobile cranes, construction cranes, machine tools and automation systems as well as high-performance components for mechanical, hydraulic and electrical drive and control technology. For more information, go to www.liebherr.com.