ROCHDALE METROPOLITAN BOROUGH COUNCIL
Town Centre DemolitionConnell Brothers were appointed by Rochdale Metropolitan Borough Council to carry out the demolition of the town centre mutli-storey car park and bus station together with the demolition of the 14 storey Municipal Offices and the associated link bridges leading to the adjacent shopping centre.
As the project progressed Connell Brothers were also awarded the contract to carry out the demolition of the adjacent St Andrews Church and Broadwater centre (highlighted in purple above) and to form a surface car park.
The Municipal offices were known as the “Black Box” locally and comprised a reinforced concrete frame with glass curtain walling cladding that formally housed the council offices. The ground floor contained a number of small independent offices and housed the escalators allowing pedestrians to access the second floor bridges. These bridges consisted of:
• Bridge A – connecting the second floor of the car park to the rear of the Municipal offices
• Bridge B – connecting the Municipal Offices to the rear of Marks & Spencer, crossing over 2 live roads, Constantine Road and Baillie Street
• Bridge C – connecting the municipal Offices to the rear of the Wheatsheaf Shopping centre
In addition there was a subway leading from the bus station through the basement of the Municipal Offices and passing under Constantine Road. The access ramp to the multi-storey car park was adjacent to the newly constructed town centre Metrolink Station adding further complications to the project.
Marks & Spencer and the Wheatsheaf centre remained open throughout the project and access for delivery vehicles and pedestrians along both Baillie Street and Constantine Road required maintaining.
Initial works comprised setting up the site compound and fencing the perimeter of the site with a mixture of timber hoarding and Heras fencing, the latter being employed to give additional temporary access points to carry out specific tasks.
Once the site was established the furniture and other loose items were removed to allow the asbestos removal works to commence to the bus station and Municipal offices. During this period discussions were held with all interested parties to develop a strategy for the removal of the access ramp to the multi-storey car park. This was required to be completed early in the project prior to the opening up of the Metrolink station to the public.
A combination of polythene sheeting, plywood sheeting and timber Navi mats were used to protect the Metrolink lines and platform. Signage was removed and the demolition works undertaken following confirmation from Metroline staff that power to the overhead cables had been shut down.
The demolition of the ramp was carried out using excavators fitted with concrete crunchers. The ramp itself was supported on central columns and the demolition works had to be carried out in a specific sequence to maintain the stability of the structure and prevent the ramp overturning.
The access road adjacent to the ramp remained open for bus traffic throughout the demolition works.
Following the removal of the main ramp structure the columns were broken down to below ground level and the footpath reinstated. The work was co-ordinated taking account of Metrolink Driver training schedules.
Once completed the protection measures installed to the Metrolink station were removed and the station was handed back to Metrolink without damage in readiness for opening to the public.
During this period of the works the structure of the pedestrian bridges was inspected and a suitable methodology developed to allow them to be removed by crane out of hours to minimise disruption to the public.
Bridge A was contained within the site boundary and this was removed by shearing through the ends of the bridge in turn and allowing it to rotate to ground level. This enabled a closer inspection of the structure to be carried out prior to removing bridge B.
The next bridge to be removed was bridge C. This bridge was of a different construction to the other bridges and comprised a much heavier steel frame to house the two travelators leading from the Municipal Offices to the Wheatsheaf shopping centre. It required removing early in the project to allow for the construction of a new entrance to the shopping centre.
Prior to its removal a stud partition was erected within the Wheatsheaf centre to prevent shoppers accessing the bridge from within. The ends of the bridge were then exposed to allow a visual inspection of the connection details prior to the removal of the bridge. At this time the travelators were exposed in readiness for their removal.
A night time closure was obtained and a 350 T mobile crane brought to site to remove the bridge. The top curved section was cut from the lower section and lifted to ground level within the site for disposal. Once the top had been cleared the travelators could be removed by carefully lifting them out and away from the Wheatsheaf Centre. This required clear communication between the signaller and the crane driver as the ends of the travelators projected into the shopping centre.
Once the travelators were free from the bridge they could be placed within the site boundary where they were size reduced and removed to make space for the main bridge structure.
The first half of the bridge to be removed was between the Municipal offices and the central supports. The main bridge beams were cut at pre-determined positions and the bridge section lifted, rotated and then placed on the ground within the site. The bridge was then size reduced and removed from the laydown area in readiness for the second section.
Once the second section had been removed temporary barriers were placed over the exposed opening to the shopping centre. The opening was then filled in using studwork and timber sheeting and a banner erected.
In order to carry out the floor by floor demolition of the Municipal offices a perimeter scaffold required erecting to the full height of the building. To achieve this a section of Bridge B required removal together with the low level offices around the base of the tower block.
Once again a night time closure was required to remove the bridge section connected to the Municipal offices.
A 350 T crane was positioned in Constantine Road the entire 25 m long first section of bridge was lifted off its supports and placed within the confines of the site.
This then enabled the platform at the rear of the municipal offices to be removed in readiness for the erection of the scaffold.
The low level offices around the tower were also removed prior to the erection of the scaffold. The structure around the offices was inspected to establish that they did not offer any support to the main tower before they were removed. Once this was confirmed an excavator equipped with a concrete cruncher removed the structure back to the main tower support legs ensuring the support legs were not damaged.
The elevation facing the bus station and car park required removal by a smaller excavator due to the location of the subway below the ground floor slab and thre limits to the load the slab could support.
Once these works were completed the scaffold could be erected to the perimeter of the tower.
Whilst the scaffold was being erected the soft stripping of the municipal offices was carried out. As the basement extended beyond the footprint of the main tower a number of props were required to be installed beneath the legs of the scaffold to transfer loads to the basement slab. The lifts were removed from their shafts and the shafts turned into drop chutes to allow soft strip material to be dropped to ground floor level. This material was then removed using a skid steer loader through a gap formed in the perimeter scaffold.
Whilst these works were underway the demolition of the multi-storey bus station was being carried out using a combination of high reach and traditional demolition excavators. The car park comprised a reinforced concrete frame with pre-cast concrete plank forming the decks. This construction allowed the half of the car park closest to the Metrolink station to be demolished first in a bay by bay manner prior to the station opening to the public.
Whilst the scaffold was being erected to the Municipal offices the next section of bridge B was removed. This section spanned over 27 m and crossed over Baillie Street to the rear of Marks & Spencer and required the road to be closed at night. It was therefore decided to remove this bridge in two halves due to the restrictions on the available space for siting a crane and laying down the bridge one it had been removed. A support frame was designed using RMD soldiers and installed in at the mid-point of the bridge sections.
With the bridge still fully supported by the existing structure the crane was attached to the bridge and operatives carefully cut through the structure to enable the crane to lift the first half of the bridge from the supports and place it within the confines of the site. Careful co-ordination was required during the removal operations to ensure the RMD support frame was not disturbed when the first section was removed. Once the first half had been removed the second half was removed in a similar fashion and the support frame lifted back within the site boundary to enable the road to be reopened in good time for the morning deliveries to the rear of Marks & Spencer.
Once the car park had been demolished and the scaffold completed a series of props were installed to the upper floors to allow for floor by floor deconstruction of the Municipal Offices. A 350 T mobile crane was utilised to lift the mini-excavators and skid steer loaders onto the roof of the tower block to commence the demolition works.
In addition to placing the demolition plant on the roof of the Municipal offices, various items of plant were lifted down. These included a telecommunications mast, control building and various items of mechanical plant.
Once the roof was clear the floor by floor demolition of the municipal offices could commence using mini-excavators were equipped with a selection of attachments including concrete crunchers and hydraulic breakers and these were utilised to carefully demolish the walls and slabs of the tower block.
The skid steer loader removed the arisings by dropping them down the debris chutes where they could be removed at ground floor level to a stockpile for further processing.
In order to utilise the drop chutes safely a specially designed steel barrier was installed at the working floor to provide edge protection. As the demolition proceeded the props below the slab were relocated to the lower floors in readiness for the demolition plant to move down the building. To avoid the need for multiple crane visits large structural polystyrene blocks were used to form a ramp from floor to floor to enable the demolition plant to move safely down the building.
During the course of the floor by floor demolition of the municipal offices the remaining bridge to the rear of marks & Spencer was removed. These works involved lifting down the concrete plank decking, steel framework that was cantilevered off the steel frame of the store and the removal of a concrete deck section and concrete support legs. Removal of both sections required road closures and crane works. The last part of the walkway also required the construction of a scaffold crash deck over a live sub-station located directly beneath the walkway.
Following the removal of the remaining bridge sections the support frame was cut back to the building frame, the openings made good with matching brickwork and block paving reinstated to the supporting columns.
The subway beneath Constantine Road was in-filled using benefil (a pre-expanded structural resin filler grout) and the ramps backfilled with site won crushed demolition arisings
Floor by floor demolition was carried out to the 4th floor with the front of the building being reduced by a further floor due to its proximity to the Metroline station. The remaining building was then demolished using high reach and traditional ground based demolition excavators. The ground floor slab and the bus station slab over the subway was removed and the basement slabs broken down to 2 m below ground level. The entire basement was then backfilled with site won crushed demolition arisings to ground level to leave a level trip free site for future construction of a temporary car park and open space area.
By developing a close working relationship between the Connell Brothers, the Client, Metrolink, Marks & Spencer and the owners of the Wheatsheaf Centre this challenging city centre project was successfully completed without incident Working together as a team enabled the works to be programmed in a manner that minimised disruption and good communication and enabled the retail businesses to schedule deliveries to avoid road closures.
The Councils new multi storey office complex (1 Riverside) was located 20 metres away from the project and provided a bird’s eye view for all employees to watch the successful deconstruction of the town centre buildings.