Glencairn tower block was built during the early 1970’s and had a steel framework construction, the structure was 17 storeys tall and contained 170 individual flats.
The project required the removal of large volumes of asbestos material that was removed by TDS, followed by the soft stripping of 170 self-contained 3 bedroom flats. The next stage was pre- weakening of the steel framed structure, this was split into 4 different sections and hinged on the first and ninth floor, giving 8 separate movements.
Client: North Lanarkshire Council
Contract: Tower block demolition, asbestos removal and site clearance
Start/end date: 2011 – 2012
Project Value: £2,000,000.00
For this particular project the high rise was demolished using explosives, which at the time was the world’s first steel framed high rise dwelling to be demolished using this method. The final stage was the processing of all resultant material and the removal and back filling of the foundations.
Planning Feasibility Studies
During the initial tendering process, this structure was directed by the client as explosive demolition engineering only. All pre -tender feasibility studies were conducted by the client and presented in the initial tender pre-construction information.
TDS Ltd were asked, as part of our submission to demonstrate the feasibility of correctly determining the design collapse mechanism as well as the expected debris pile formation and any environmental impact. Following the contract award, we were informed that TDS were merited as submitting the most comprehensive tender submission regarding ability and understanding of how to safely undertake the work.
Pre – start information submitted to client and client’s representative CDMC
On award of contract and as required under CDM regulations:2007 the client issued a fully completed pre- construction phase plan detailing all known and expected health, safety and environmental objectives, service locations, historical and geographical importance requirements.
As with all contracts to be undertaken and following a further in-depth feasibility study conducted by the TDS management team, the client and the client’s representative were given a more in-depth construction phase health and safety plan developed further from the pre-construction phase plan which was submitted as part of the original tender. The client and his representatives were also given the initial project specifications, risk assessments and method statements on the topics below.
- Establishment of the site and welfare facilities
- Securing the site and protection of the public
- COSHH Risk Assessments
- Asbestos removal procedures
- Soft stripping
- Waste management plans
Throughout the duration of the initial part of the project, any changes required to the first draft of risk assessments and method statements were amended, logged then re issued to be signed by all parties.
During the remainder of the project, further risk assessments and method statements were created and issued with regards to:
- Structural reports
- Designed pre -weakening
- Designed explosives and mechanism’s
- De mobilisation and re mobilisation of welfare
- Blow down manuals
- Initial debris pile clear up
- Processing of debris pile
- Removal and processing foundations
As the diagram above clearly demonstrates this structure though not complex in its erection or design characteristic’s, still required a specialist and recognised contractor to safely demolish it.
Whilst acknowledging that steel structures, if not design mechanism controlled, will descend where the structure wants to collapse, TDS where recognised and accredited for this safe form of demolition which demonstrated our ability, knowledge and professionalism in undertaking the work.
During the initial tender period and project design stage, due consideration was given to the proximity of the neighbouring properties, it was established during the tender stage that the explosive demolition of this structure could not be concluded safely in a standard collapse mechanism, as conducted during all previous concrete structured blow down’s, nor would the building fit between its own foot print and the neighbouring properties if toppled. The safest method to demolish this structure was to separate the building into four sections then double hinge the separated sections (as shown above).
The Design Team
Prior to explosive demolition our in-house design team of qualified Engineers and experienced demolition experts, designed the following:
- Soft strip ejection techniques
- Instruction for demolition of none loading bearing walls
- Creation of explosive sand bag platforms that connected to existing vertical steel stanchions to eradicate un controlled premature collapse of weights imposed
- TDS engaged the services of an industry recognised explosive engineer who was duly assisted by the TDS management. The dedicated pre-weakening team methodically worked to the strictest parameters to enable the exact execution of the pre-designed collapse pattern to be achieved.
A close working relationship was quickly established with the client and the client’s representatives, this enabled efficient, proactive solutions and conclusions to all project objectives.
The relationships established, facilitated a team spirit approach and was witnessed by all during blow down day. All the hard work conducted by the site management team, as well as the dedication and methodical yet sympathetic approach of our local liaison officer and the overall management by our project director, which concluded in a text book blow down and clean-up operation.
Extensive planning took place to ensure a safe demolition for all involved. The liaison officer and project director worked tirelessly to collate many hundreds of names and telephone numbers for residents, businesses and community associations affected by the Sunday afternoon blow down. More than 270 people were evacuated between 08.00hrs and 10.00hrs in a seamless exercise, exiting through 2 police-controlled check points, during specific exit times to ensure all parties were accounted for. Throughout this period of evacuation local housing association teams double checked all properties at risk to ensure complete and thorough evacuation.
During the post blow down review meeting, the client and respective emergency services commended the professionalism displayed by the TDS team, moreover they commented on the simplistic methodical approach undertaken whilst maintaining care and due consideration to those parties affected by the exclusion zone.
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 revisions