Brextor for pile breaking
Due to the increasing density of construction methods and building in exposed locations, pile foundations are becoming more and more important. Previous pile breaking methods pose dangers that can be avoided with the newly developed and patented Brextor method which is manufactured in Switzerland by BRC Engineering AG.
The available building ground globally is increasingly in exposed locations and of poor load bearing capacity. In such circumstances, pile foundations are the solution to ensure a secure foundation, and for this reason, pile foundations are becoming increasingly important. The pile head is the connection to the foundation, whereby the highest quality is required, as a failure of the foundation can end in disaster.
Up to now, bored piles have mainly been processed with air or hydraulic hammers, whereby the processing energy cannot be controlled. As a result, there is a risk of cracks in the concrete body and spalling on the outer skin of the pile. This can lead to corrosion damage in the medium term. Bent or cracked reinforcements also reduce the ability to absorb the tensile load. The use of hammers requires a correspondingly large working area. In addition, narrow and long reinforcements are difficult to work with and if spiral reinforcement is present in the excavation area, there are major obstacles. To ensure quality and break the surface tension, a cut must also be made to the final height, whereby the last 30-50 mm can only be done by hand.
Brextor system
With Brextor, the horizontal force enables 100% control of the processing energy used. The pile head is transferred precisely to the downstream trade (height accuracy +/- 1 cm). In addition, the concrete structure and the reinforcement remain intact. The core tension is broken with the inner cutter and the surface tension with the outer cutter. The remaining concrete edge can be removed with the ‘BRC’ pile head crusher without risk of damage. The finished pile head is achieved in four steps: prepare the pile with the milling disc, mill to height (+/- 1 cm height accuracy), remove the residual concrete with the pile head crusher and clean and align the reinforcement.
The design of Brextor allows it to be used in very small or no side workspaces. This saves excavation work, as the cut is made automatically at the finished excavation height with the external milling cutter. Brextor is suitable for all types of piles/walls, using one system for all operations.
Four-lane expansion
Brextor was used for the four-lane expansion in Liestal, Switzerland, which was carried out by Implenia. “Manual removal by hand would always run the risk of damaging the reinforcement and disturbing the concrete quality at the pile head. I can eliminate this risk with the Brextor,” says Stefan Lang, site manager at Implenia. “The time pressure on this construction site is great, as various milestones have to be met. We only have a limited time window available and if this cannot be massively extended, such an undertaking without Brextor would only be possible with a lot of effort and personnel.”
In addition to the decisive factor of time, there was the challenge of very limited space. Stefan Lang explains: “We would also need more space, which would be a big challenge here, because there is not enough room between the nail wall and the pile head for a jackhammer. For this reason, the up to 6 m high wall would have to be set back over a length of 300 m in order to create enough space for pile head processing. This would mean a massive increase in costs. Thanks to Brextor, you can save these costs.”
If the railroad line was extended, 80 cm of working space could be dispensed with at the rear. With an embankment height of 6m, this results in 1,440m3 of excavation (fixed dimensions) over a distance of 300m, which did not have to be carried out. In addition to the enormous cost savings for excavation, transportation, landfill fees and material replacement, the case shows that Brextor also makes a major contribution to the environment. At least 280 truck journeys of 40 km each were saved. This reduced the carbon footprint and residents benefited from a less polluted road network.
