Technical Demolition Services Limited successfully and safely undertook a country’s biggest ever blast, during our high rise, tower block explosive demolition project.
This record-breaking venture was undertaken by Technical Demolition Services utilizing the expert assistance of PDC. At 2.00a.m., 29th November 2009, Glasgow, Scotland, three pairs of 20-story double tower blocks, each 55m high comprising an estimated 100,000 tonnes of reinforced concrete and masonry, were blown down.
By using Hotshot electronic (digital) detonation system innovative planning proved to provide complete success to a project situated in a critically confined urban residential location.
Contract: Explosive Demolition of Tower Blocks
Client: GHA Glasgow Housing Association
Start/End Date: 2011 – 2012
Total Project Value: £2,000,000.00
Technical Demolition Services had every confidence in utilizing this type of detonation system. Only a year earlier we had pioneered the future of explosive demolitions by attempting a world’s first high rise demolition using hotshot system. Our engineers were impressed with this technology offering the ability to precisely set the detonator timings to within 1 millisecond. This awarded our demolitions accuracy, never before available in conventional pyrotechnic detonators.
During our blast design planning, the desired movement between mobilised structural elements was determined and translated to the detonation timings required to create ‘drop between sections’. This optimally used the influence of connected elements of the building to direct the movement of structure to the precise position on the ground available to accommodate the debris pile. The specific delays required to achieve this effect would never be available with conventional detonator systems.
Through understanding the fundamental principles determining structural movement after initiation, delay timings were determined creating a specific effect on the structure. Considering the previous drop of each structural element and successive vertical displacements, delay timings were chosen maximizing lateral movement induced across a structure to direct the building in a specific direction.
I was not just our understanding of the fundamental principles; we were delighted to welcome the Security Service MI-5 to site to view at first hand the intricacies and complexities of our approach to explosive demolition. Our project provided the perfect teaching aid allowing our experience to be passed on to continue the security services’ fight against terrorist threat and attack.
We appreciate safety is of paramount importance when undertaking all our demolitions. The key to ensuring a confined blast with no damage and the highest levels of safety is attention to detail. Understanding the critical safety distances for exclusion zones, which differ from demolition to demolition, and relating them to a myriad of inter-related factors ensure safety remains priority.
Building wrapping minimises displacement. Wire chain link fencing combined with geo-textile fabric is employed to contain explosively displaced concrete fragments at source and around the perimeter of the structure. The ability of primary wrap materials is to contain explosively displaced concrete, was first proven by trial blasting and in this blast, 40g/m legs, and walls. Additionally, intricate, and painstaking checking is required ensuring no apertures or imperfections allow debris scatter.
Our commitment to expertly protecting the immediate area is complimented by our understanding that a successful project must involve, and firmly commit to, the local community. Planning is only one key element of the project. Regular community liaison ensures we work not only for, but with, the local community Centre, liaising at the heart of the community accompanied regular newsletter delivered door to door. Programmes of talks to local children proved popular.
With such ongoing links with the community, moving residents out of the exclusion zone and into hotel accommodation during the explosive demolition was efficiently undertaken, with residents and local businesses supporting our operations.
The environmental impact was managed effectively. Due to the close proximity to buildings including low rise flats, homes and a shopping complex, it was imperative we established control of debris spread, utilizing a moat and earth mound alongside rubble filled ‘containers’ to form debris spread retention barriers. These preventative procedures allowed the movement for drop of tower blocks to be precisely planned, and finally executed to perfection resulting in no migration of debris.
Homes, local shops, and commercial premises, all required protection from dust. To prevent environmental disruption, we deployed “dust boss” water screening and geotex protection together with teams of post blow down operatives working through the night and following day to expertly clean and return normality to the area as quickly as possible.
The demolition itself proved a unique, crowd drawing spectacle, illuminated by high powered lighting and lasers focused on the structures offering a dramatic and thrilling back drop to an explosive finale.
As with any contract completed, TDS will issue the client with all the relevant and necessary documentation:
- All demolition drawings, superimposed over footprint of the site
- All service capping locations
- All live services that remain on completion of project
- Other uncovered structures/ apparatus discovered during foundation removal
- Location of adjoining structures
- Completed construction phase plan
- Copies of all risk assessments and method statements, final revision