The two tower blocks were constructed during the 1960’s using traditional shear wall construction techniques, these structures were 21 stories tall & housed 126 individual flats.
This project required the removal of all asbestos contained materials, soft stripping of 252 self-contained three bed room flats, demolition using high reach technology, the processing of all resultant material, followed by the removal & back filling of foundations.
Client: Glasgow Housing Association
Contract: Tower block demolition, asbestos removal & site clearance
Contract Start/End: 2011 – 2012
Total project Value: £1,000,000.00
Planning & Feasibility Studies
During the initial framework tender process, Glasgow Housing Association required the demolition to be completed either using a high reach machine or with the use of explosives.
All pre-tender feasibility studies conducted by the client were replicated in a pre-construction health & safety pack as directed under CDM regulations: 2007 & presented to all framework contractors.
TDS Ltd where asked as part of our tender submission to create a method statement for our chosen method of demolition (high reach & or explosives).
Following numerous site feasibility studies by the management team of TDS, high reach demolition was chosen as the safest & best method, we came to this decision based on the information contained within the pre-construction pack, the existing structural design of the buildings & more over the close proximity of existing residential dwellings.
Pre-start information submitted to the client & the client’s representative CDMC
On award of the contract, it was acknowledged by all parties that the tender stage pre- construction pack was a true, accurate reflection of all the risks & objectives, additionally a construction phase health & safety plan was generated by TDS.
Site specific risk assessments were given to the client & his representatives for due consideration prior to initial establishment on site:
- Establishment of site & welfare
- Erect hoarding
- Securing the site & protection of the public
- COSHH assessments & risks
- Asbestos removal
- Waste management plans
Throughout the duration of the initial part of the project, any changes required to the first draft risk assessments & method statements were amended, logged then re issued to all parties concerned.
During the remainder of Ibroxholm terrace, further risk assessments & method statements were created & issued:
- Soft stripping
- 3D models – used as a working desktop tool
- Structural reports
- For the safe delivery of the high reach excavator, this required the use of 3 trucks, one low loader for the excavator, one low loader for the arm & a flat bed for the ballast, travelling from Ipswich.
- Demolition using high reach machinery
- Processing of resultant materials
- De-mobilisation & re-mobilisation of welfare, for the 2nd multi story.
- Removal & processing of all foundations
Complexity of the Demolition
The structures though straight forward in construction had central corridors on every 3rd floor, this enabled persons to enter their accommodation, however the accommodation on one side had living quarters at corridor level then bedrooms above, whilst the opposite flat had the bedrooms below the living areas.
To enable the safe demolition of these buildings using high reach technology, whilst maintaining the structural integrity, our engineering staff created a virtual 3D model of the structure to facilitate a daily virtual de-build.
This 3D technology enabled the site management team to de-construct the structure, giving us the ability to study the potential effects of the days planned works & identified potential structural stability implications prior to live demolition. Subsequently the 3D technology permitted the management team to sit alongside the high reach operator every morning, to aid the de-construction of the building together, prior to the work commencing.
As expected, this chosen 3D technology assisted a true working relationship between the super high reach operator & the management team, leading to the safe demolition of a truly complex structure.
The Design Teams
Prior to the super high reach demolition, our in-house design team of qualified engineers & experienced demolition managers designed the following:
- Safe & efficient movement of the super high reach demolition excavator, from low-loader to site entrance, being mindful of road configuration, overhead cables & load bearing pressures.
- Intense study of the structure’s construction leading to the creation of virtual 3D models
- Daily desktop de-construction meetings, to assess potential structural instabilities during proposed daily demolition periods, thus maintaining a virtual & factual safe method of demolition.
As with many other projects conducted for & on behalf of the GHA framework, our close working relationship continued to flourish thus strengthening an already entrenched professional association between our two organisations.
This mutual team spirit aided & assisted this delicate demolition, as all parties recognised & collectively worked towards achieving the objectives & goals set, of zero accidents & zero incidents.
The local TDS liaison officer was quickly able to establish a healthy working relationship with surrounding neighbours thus mitigating any potential adverse reaction from residents who may object to the contract duration envisaged. She would not only advise residents via a regular newsletter but would communicate personally with any person or persons no matter how trivial.
As with any contract completed, the project manager will issue the client with all the relevant documentation:
- Demolition drawings, which were superimposed over footprints of the sites
- All service capping locations
- All services that remained in the ground on completion of the project
- Other uncovered structures/ apparatus discovered during foundation removal
- Location of adjoining structures
- Completed construction phase plan
- Copies of all risk assessments & method statements as well as final revisions