The piling rig LRH 100.1 unplugged is one of the latest models in the electrically driven unplugged series from Liebherr. Fitted with a new-gen hammer H6, it has found its first jobsite in Sweden. Hercules Grundläggning AB, which specialises in building foundations, is using this model to drive nearly 300 concrete piles into the ground and is very satisfied with the first performance.
Mats Andersson operates the piling rig LRH 100.1 unplugged on a jobsite in Karlstad, Sweden – where a building complex with apartments, offices and ground floor shops is currently under construction.
It’s the first application and endurance test for the battery-powered piling rig from Liebherr, and Mats says he is pleased to avoid the exhaust, noise emissions and vibrations that normally come with the job.
“I am retiring in two years. It is very nice to operate such a machine for the last few years,” he said.
In order to transfer the load of the building into load-bearing soil layers, Hercules Grundläggning AB is driving piles into the ground with the LRH 100.1 unplugged. “We are installing 284 piles with sizes of 270 x 270mm and lengths between 15 and 20 metres,” he said.
Flexible for all piling conditions
The LRH 100.1 unplugged excels with its large working range. A radius of up to 8.7 metres has the advantage that the machine does not have to be constantly moved. The design of the leader enables inclinations of up to 18° in all directions. Furthermore, it is also possible to raise or lower the leader by 4m (e.g., when working in a foundation pit), making the machine more flexible.
For the piling work, Hercules Grundläggning AB has equipped the LRH 100.1 unplugged with a Liebherr hammer type H 6. The hammer is modular and can be used with drop weights of between 3 and 6 tonnes, depending on requirements. At the jobsite in Karlstad, Mats drives the piles into the soil with a 5 tonne weight from a drop height of 400mm.
Liebherr product manager Michael Rajek says the company is using a free-fall hammer – rather than an accelerated one.
“We only compensate for the power loss with the cylinders. This has the advantage, especially when driving concrete piles, that these are not damaged so much as when using accelerated hammers,” he says.
Depending on the length of the pile, between 800 and 1,500 strokes of the hammer are necessary for each one. In only 10 to 20 minutes, Mats can lift the pile and drive it into the soil.
“The control 1/4 system is designed in such a way that the operator can now adjust the pile-driving energy and the number of strokes independently of each other, and thus ideally adapt to the conditions,” Michael says.
“We have more or less changed the whole architecture of the existing H 6 hammer. The new steel construction is specially designed for stiffness, longevity and for reliability.”
The noise reduction on the jobsite due to the battery- powered piling rig was also continued with the new generation hammer, which has a soundproofed pile helmet and pile helmet guide.
Due to the redesign of the hammer, the noise emission has been reduced by about 35 per cent.
Performance, safety and zero emission
The electro-hydraulic drive of the LRH 100.1 unplugged has the same performance specifications as the conventional version. Both are operated in the same way, which is especially convenient for machine operators if they often have to switch between machines.
The Ground Pressure Visualization of the new piling rig calculates the current ground pressure in real time and compares it with the specified safety limits of the relevant jobsite. The ground pressure is displayed in the operator’s cabin. This means the operator is permanently aware of whether the machine is situated in, or is approaching, a critical area.
One exceptional feature of the electric drive concept is Zero Emissions. The unplugged machines of this series do not produce any exhaust fumes and are extremely quiet. This strikes the right note, especially in noise-sensitive regions. and finds favour with construction site personnel like Mats Andersson.
The battery charges with a conventional jobsite electric supply. “That was no problem at all,” Mats Andersson said.
Operation can continue as normal while charging. In order to change to battery operation, the operator just needs to pull out the plug, therefore: unplugged.
Whether attached to the electric supply or not, the performance and range of application remains unchanged.