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The
Project involved the demolition of bomb-damaged structures,
which included a nine-storey building comprising of a two-storey
retail Marks & Spencer store, with Michael House, a
six-storey office block, located on the podium above the
Plant Room.
Michael House was supported by five pre-stressed
post-tensioned beams, which in turn were supported on columns
passing through the two storeys of the store to sub-basement
level. Particular attention to detail was required with
the specialist techniques involved in the de-stressing/dismantling
of the post-tensioned beams. The Project also called for
the demolition of retail units along St. Mary's Way and
an office block (Macintosh House) to the northern elevation
of the busy Shambles Square Plazza.
Once the structures were demolished, the
entire area of the site was to be brought down to sub-basement
level (two storeys below ground), involving fabrication
and installation of specialist propping, to undercroft areas
and demolition of below ground car park areas.
Connell Brothers adopted an innovative
approach from early Tender Stage of the Project and throughout
the execution of the works.
Due to the location of the site and building
construction, Connell Brothers appointed Dr. John Roberts
of Allott & Lomax Consulting Engineers, to deal with
aspects of the structural tower, and the University of Manchester
Institute of Science and Technology to carry out monitoring
for the de-stressing of post tensioned beams.
As the Project proceeded, Connell Brothers
had to also adopt innovative and flexible methods of demolition
in restricted times during the working day, employing percussion
and non-percussion procedures to minimise noise and vibration,
etc, to high street retail operators, telephone call centres
and which remained open whilst the works proceeded.
The Management of the Project was carried
out in close liaison with Bovis Construction Ltd. The Project
was headed by Mr. B. Connell, Projects Director, with Site
Supervisors, Foremen, Safety Advisor, Structural Consultants,
Monitoring Consultants and a team of highly trained (CITB)
demolition Operatives and machine Operators.
The Management called for regular Safety
Audits of the site, weekly Tool Box Talks with regards to
safety, regular Method Statement Induction courses for all
Operatives on site, weekly Safety Meetings with Bovis Construction
and weekly Progress Meetings with Bovis Construction. Regular
auditing was undertaken by Bovis Construction to ensure
that the Project Management procedures were followed.
Because of the specialist nature of the
Project, Connell Brothers had budgeted within their Tender
Costs for an amount of additional investment for plant/equipment
for a specialist long reach excavator capable of reaching
30 metres, executing the works. The investment also included
for procurement of city hammers, concrete cutter crunchers
and specialist hand held silent concrete crushing, cutting
and bursting, equipment.
A flexible approach to working was adopted
in conjunction with Bovis Construction as the works proceeded.
The site was bordered by high street retail operators, hotels,
office blocks, tele-sales offices. Varying methods of operation
were adopted at various times of the day, in order not to
cause disruption to a densely populated retail/commercial
centre, which was recovering from the effects of the bomb
damage.
The Project, as described in the introduction,
took seventeen months to complete, with a value in excess
of 2.5million pounds. The Project works were phased, with
set completion times, dates and costs for each stage and
were completed according to time and cost.
Due to the densely populated commercial
location of the site, Connell Brothers were keenly aware
of the environmental awareness required on a Project of
this size and nature. Detailed noise assessments were implemented,
coupled with out-of-hours working, to ensure none or very
little disruption.
Dust arising from the operation was also
a main factor for consideration and the Project included
regular suppression of dust, by hosing techniques and the
installation of wheel washing facilities for all vehicles
leaving the site. In addition, all vehicles leaving the
site with debris were fully sheeted, as part of the suppression
procedures.
Throughout the works, safety to all Personnel
on site and the General Public was of paramount importance.
A strict regime of safety procedures was implemented and
Connell Brothers can report that no notifiable incidents
occurred from commencement in November 1996 to completion
in March 1998.
The Project has been acclaimed by leading
engineers in the industry as a 'world first' and we attach
photographic and editorial material detailing the stages
of demolition.
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