Drilling instead of pounding
“We deliberately chose the Fundex method to use here in Andermatt – in order to avoid any unnecessary nuisance of noise for the residents and visiting guests”, explains Björn Hübner, Deputy Project Manager of NV Besix SA at the company’s Swiss subsidiary. Working steadily, large machines hydraulically screw the heads of drill tubes deep into the ground (1). “The head looks sort of like a screw. It compacts the soil all around it and it eliminates any need for excavation. This means that there is no change in the water table.”
Once the head has been sunk into the ground, the required reinforcement is inserted into the tube (3). “Because soil conditions differ from here to there, we don’t drill every tube to the same depth. With this method we can use the exact amount of steel reinforcing that is statically necessary. So this method is not only low in noise and vibration, it’s also environmentally friendly.” For Björn Hübner this is another, more convincing, advantage of the Fundex method. After the concrete is poured (4), the tube is extracted while being rotated in alternate directions (5). “The back and forth rotational movement compacts the concrete, resulting in the profiled outer surface of the pile. The drill head remains in place when the tube is extracted. It serves as the pile footing.”
Over 750 such pilings over an area of 9,700 square metres are needed to prepare the subsoil for the second hotel. They are drilled into the ground up to 27 m deep. “Progress has been very good so far – of course, thanks to the good weather. Should this continue for a little longer, we will begin with the concrete work for the basement already this year.”
The hotel is scheduled to open in 2018. In addition to bars and restaurants, it will also feature a conference and event centre. The project also includes a residence wing – the so-called Gotthard Residences – as well as a new indoor pool with wellness centre.
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