UNIVERSITY OF MANCHESTER Demolition
Manchester Engineering Campus Development (MECD), Grosvenor Street, ManchesterFollowing a stringent pre-qualification process and a successful tender submission Connell Brothers Ltd (CBL) were appointed to carry out the demolition of a number of different buildings as part of the University of Manchester’s redevelopment of the Engineering Campus located on Grosvenor Street in the centre of Manchester.
The site was adjacent to the busy A34, a main route into Manchester, as well as the Aquatics Center and the newly opened Graphene Building. The buildings were mainly 4 storey student accommodation blocks to one side of the central access road, forming Phase 1 of the works (Yellow), and the 5 storey Materials Science building forming Phase 2 (Purple).
Phase 1 of the works involved the demolition of the Grosvenor Hall Groups of Buildings which included the Grosvenor Place, Grosvenor Street Buildings, Bowden Court 2, Bowden Court 3 buildings and Ronson Hall of Residence.
Prior to commencement of the demolition works a semi-permanent perimeter hoarding was erected around the site and a full length trench was also excavated around the perimeter to determine the location of any incoming services. The main communications service duct for the university was located adjacent to the access road running through the centre of the site and this required protecting throughout the demolition works.
Asbestos was identified throughout every building and this was removed by a Client nominated sub-contractor under the supervision of Connell Brothers in-house Asbestos Manager. Additional asbestos containing materials were discovered during the course of the soft stripping works and this required close co-ordination to ensure it was fully removed and that ongoing soft stripping activities did not affect the asbestos removal works. Dust was a major issue on site due to the close proximity and sensitive nature of the adjacent Graphite building. Connell Brothers designed and built a purpose made debris chute for the removal of the soft strip from these buildings. The chute design enabled a roll on-off skip to be placed directly underneath and the high sides helped prevent the spread of dust. During this period scaffold was erected to various elevations of the buildings in readiness for structural demolition to commence.
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The first structures to be demolished were the included the Bowden Court buildings and Ronson Hall. The three blocks were four storey’s high and of a conventional construction, having brick external walls and lightweight load bearing concrete block walls within. The Ronson block had precast concrete panels forming the floors with a pitched timber roof.
The Bowden blocks had precast reinforced concrete beams with concrete infill blocks forming the floors and the roofs and as such demolition of these blocks was carried out using a remote controlled Brokk to reduce the height of the buildings until they could be demolished using traditional ground based demolition excavators.
The Ronson block was demolished by mini-excavators utilising the floor by floor demolition technique to reduce them in height prior to demolition being completed by traditional ground based demolition excavators.
Following the demolition of the three accommodation blocks the ground floor slabs and foundations were removed and the arisings stockpiled for crushing. The works then progressed to the remaining buildings in Phase 1, the Grosvenor Place and Grosvenor Street Buildings. The Grosvenor Street building was a standalone four storey brick structure with concrete plank floors and a pitched timber roof. The Grosvenor Place building was a series of long thin five storey buildings forming an S – shape connected at the ends by common staircases. Their structure also consisted of brick walls with precast concrete plank floor and edge beams and a flat roof.
Demolition of the Grosvenor Place building commenced first following the erection of a protection scaffold to the elevations facing the perimeter of the site and the installation of props to the floors to allow mini-excavators and skid steer loaders to be placed on the floors to carry out floor by floor demolition of the structures. The perimeter of the floors had a large precast concrete beam at floor level which, in conjunction with additional metal and pedestrian safety barriers, provided a safe working area for the plant.
A mobile crane was brought to site and the plant lifted onto the building adjacent to the scaffold. An opening was then broken out and the plant lowered to the floor below. Windows to the rear of the building were removed and as demolition progressed the skid steer loader was utilised to remove the debris via the window openings into the drop zone. The mobile crane was also utilised to remove the concrete beams from the rear of the building as demolition progressed. Once the height of the building had been sufficiently reduced the remaining structure was demolished using a combination of high reach and traditional demolition excavators.
Following the removal of the section of building adjacent to the Grosvenor Steet building demolition of this structure was carried out using a combination of floor by floor demolition and a high reach demolition excavator.
Scaffold was erected to the elevations facing the perimeter of the site and props were installed to the floors in accordance with the propping plan to enable mini-excavators and skid steer loaders to be placed on the floors.
Once the preparation works were complete the timber roof trusses were seperated from the structure by operatives using hand tools and then removed by the high reach excavator using a rotating grab.
Once the preparation works were complete the timber roof trusses were seperated from the structure by operatives using hand tools and then removed by the high reach excavator.
Following the removal of the roof a mobile crane was brought to site and the mini-excavators and skid steer loaders placed on the floor slab to commence the floor by floor demolition of the structure.
Demolition then continued floor by floor with the scaffold being reduced as works progressed before the remaining structure was demolished using the ground based demolition excavators down to the top of the ground floor slab.
Once the Grosvenor Street building had been demolished the demolition of the Grosvenor Place buildings continued.
Of particular concern during the remaining demolition of the Grosvenor Place buildings was the close proximity of the Aquatics centre which remained in continual use throughout the demolition works. Once again scaffold was erected along the elevations adjacent to the Aquatics Centre, props were installed to the floors, and the previously proved method of floor by floor demolition was employed to reduce the height of the structure adjacent to the Aquatics Centre. As previously utilised ground based demolition excavators were then employed to complete ythe demolition of the building with no disruption caused to the adjacent building operations.
Throughout the project Connell Brothers adopted an open and proactive approach to the works and were actively engaged in promoting the demolition industry to the students of the University. In addition works were suspended throughout the project to ensure students taking exams were not disrupted by on site activities.
Students were invited onto the site to witness first-hand the processes involved in carrying out a complex demolition project. This did not only involve the activities at the work place but also all the work required by numerous parties prior to works commencing and throughout the demolition process to ensure a successful outcome.
Another interesting involvement was the visit by the Chinese Premier. As part of the his visit to Manchester The Chinese President, President Xi Jinping visited the “world leading” National Graphene Institute at the University of Manchester which is located across the road from the busy demolition site.
Connell Brothers site management team provided full co-operation with Greater Manchester Police to ensure there was no disruption to the visit and further ensured that an adequate area was provided adjacent to the site for spectators.
During the President’s visit the works were suspended in the immediate area of the Graphene Institute which is located some 30 metres from the MECD development and quiet working undertaken to the remainder of the site.
Following the successful completion of the Phase one demolition works the site was enlarged to incorporate the Materials Science Building. Demolition of this building once again involved the use of floor by floor and high reach demolition techniques. During these works the ground floor slabs and foundations to the buildings in Phase One were removed and all suitable demolition arisings were crushed on site for reuse.
An interesting addition to the Materials Science Building was a steel framed structure to the gable ends. This structure was removed to one end prior to demolition commencing due to its close proximity to adjacent buildings. Scaffold was erected to the gable end of the building and the structure removed using a mobile crane prior. The gable end was then demolished using mini-excavators to a suitable height before the scaffold was removed and the remaining building demolished using a combination of high reach and ground based demolition excavators.
The Materials Science Building was constructed with a basement and as a result the rear of the building was significantly lower than the front. Part of the works involved the removal of the topsoil to the rear of the building to enable the entire area to be backfilled to the road level following the demolition of the building.
The embankment to the rear of the Material Science building was excavated into steps and backfilled to provide a stable area for the re-routing of cables. Once these works had been carried out and the demolition of the building completed the entire area was backfilled in compacted layers using site won material with the remaining material being stockpiled on site for use in future works.
This material was also used to backfill the areas where building were located in Phase One of the works following the removal of the ground floor slabs and foundations. Throughout all stages of the backfilling CBR tests were carried out to ensure the ground was sufficient to enable the use of piling equipment. The levels required across the site varied and upon completion a full topographical survey was carried out to confirm compliance with the requirements.
This project presented a number of challenges, namely:
- The tight nature of the site and large number of live services present
- The close proximity of live buildings
- The close proximity of university buildings
- The large amount of asbestos materials that required removal
- The very different type of construction of the buildings