Construction site of the week – Silo blasting in Brüggen

Demolition of the “chip bunker” – longfront or demolition?

The so-called “chip bunker” on the site of the former Terstappen upholstered furniture factory in Brüggen-Bracht had to be demolished. The initial question was whether the longfront should be used for the demolition or whether blasting should be considered. When choosing the method, the building structure, its condition, the adjacent neighbourhood and the space available on the demolition site were evaluated and taken into account. After inspection and assessment, our member company, Deutsche Sprengunion, came to the conclusion that blasting was a possible demolition method. The client wanted the height of the building to be reduced to no more than the shorter floor plan length of 6.5 m and the greatest possible destruction through a hard impact on the concrete floor slab of the adjacent neighbouring hall. This blasting target was guaranteed by Deutsche Sprengunion.

After the bid was submitted, Deutsche Sprengunion has won the direct comparison with the use of an excavator with a long front boom and was awarded the contract for the blasting. The next step was the planning. A static calculation was carried out in order to minimize the amount of explosives used, among other things.

The challenges

With a floor plan of 6.50 m x 9.50 m and a total height of 24.5 m, the silo was the smallest but also the tallest structure to be demolished on the construction site. Other challenges included the blasting target and the construction of the silo, which had a false ceiling at a height of 2.05 meters. In case of doubt, this ceiling could have ensured that the silo would settle too early and without sufficient inclination on the intermediate ceiling and not tip over.

For the blasting, 8 kg of explosives and 51 detonators were placed in the silo. Rubber mats were hung in front of the blasting points to provide a secure cover. The adjacent roads were closed off by the responsible police department in cooperation with the public order office. Special attention was also paid to the daycare center, which was located around 130 meters from the blasting site. A favourable time was therefore discussed with the daycare center management in advance, which suited the daily routine of the facility and the schedule on the day of the blasting.

Day of the blasting

On the day of the blasting in December 2023, the representatives of the authorities gathered at 11 a.m. for the final meeting and safety briefing. Those responsible received the last missing confirmation from the public order office. The area to be cordoned off was clear of people and the detonation took place at around 3 pm. The silo tipped quickly and cleanly to the side in the desired direction. The front wall of the silo was already completely destroyed by the impact, the rear wall collapsed and lay in several pieces on the front wall. The vibrations measured on residential buildings remained below the reference values.

Thanks to exemplary cooperation with the customers and good teamwork between the authorities involved and the neighbourhood, the demolition was a complete success for everyone. The very next day, the silo was completely crushed and separated from the steel scrap using a Caterpillar 323F.

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You can find the full article in ABBRUCH AKTUELL 01/2024 on page 32 (only in German).