Complete Demolition of 100m High Reinforced Concrete Chimney at Bellozanne EfW Plant, St Helier, Jersey.
The chimney structure was constructed from reinforced concrete and stood 100m above ground level with a respective base and summit diameter of 6.57m and 5.63m. Internally the chimney housed 3 No. brick and steel constructed flues which were supported on an array of 10 No. reinforced concrete floor slabs. Other than the bottom 20m of the concrete windshield, which was demolished using a high reach machine, the full height of the chimney was demolished in a piecemeal fashion. This mammoth task was carried out by a select team of highly trained and experienced steeplejacks over a 22 week target schedule.
To provide safe and suitable access for the demolition, a specialised modular frame scaffold platform was installed at the summit of the chimney. This scaffold platform is designed and installed in such a way that it can be lowered as the demolition proceeds. However, before the chimney could be reduced in height all internal components, such as the 3 No. brick/steel constructed flues and 10 No. reinforced concrete floor slabs, would need to be demolished first. This was carried out using a man riding winch complete with steel gondola for access. To view the removal and final descent of the upper most concrete floor slab please click on the video below.
With the chimney void now empty the demolition of the main concrete structure could now commence. This procedure was carried out in a piecemeal fashion. Rivet busters were used to break away areas of concrete to expose the steel reinforcing. Once exposed the reinforcing steelwork was cut with flame cutting equipment, allowing a panel of concrete fold in and gravity to take effect, with the concrete panel falling to ground level within the void of the chimney.
The contract was successfully completed ahead of schedule without any safety incidents and to the full satisfaction of the client. Mr Peter Wilkinson, Principle Engineer on the project for the States of Jersey was kind enough to write a letter of commendation following completion of the works. To read the letter please click on the following link Letter_Rafferty 230914 reference.
We would like to personally thank Peter and all involved for their support and allowing Rafferty’s to be of service to them and the States of Jersey on this contract.
The following photographs show various stages of the demolition.