The challenge
The neo-Renaissance frontage to Barclay House, located on Manchester’s historic Whitworth Street West, will enclose 90 stylish new apartments; aimed at city workers and those wanting to base themselves close to the expanding academic institutions. The crucial basement area will contain a gym, social space and ‘Metropolitan living’ single bedroom pods, while planning permission is pending to create an additional 30 apartments within two planned new upper floor levels.
Due to the complexity of the reconstruction challenge, main contractor and refurbishment specialist, Armstrong Projects Ltd called on us to consult on supplying the most effective temporary works solution possible. That solution had to facilitate the safe demolition of the old core, followed by the insertion of steel columns from a new 300m³ basement foundation slab, right up to the top of the existing building at the fourth-floor level.
The developer’s ambitions to extend the building upwards, and other necessary refinements to the method statement – including the exact position of the new basement foundation slab – led to our own engineers calculating the precise loadings to be supported. Armstrong Projects, meanwhile, cast a series of pads as temporary footings for our propping systems.
Our solution
This resulted in our team designing, fabricating and installing 20 tonnes of support steelwork – featuring Mass 50 propping units, together with specially strengthened 12.5-metre-long transfer beams and stools, to bridge the foundation works. Special fabrications were required to not only provide the 50 tonne capacities, but to also ensure the components could be manually assembled, while a winch was used to lower everything through the void in the ground floor slab.
In addition to this, we also supplied Hymat hydraulic and mechanical jacks to pick up the loads from the back-propping above, which in turn made use of Mass 25 and System 160 propping to support the upper floor slabs.
The Managing Director of Armstrong Projects, Chris Hamlett, commented: “Our team had experience of working with Mabey Hire a few years ago in London. With the Barclay House contract, there were a number of challenges, including the client’s desire to add a further two and a half storeys at roof level to create more apartments.
“Mabey Hire was able to offer us a solution to accommodate these changes including, most importantly, a bridging structure which we could work underneath; to enable the construction of a new 10m x 10m, three-metre-deep foundation within the basement to carry the new steel structure.
“By completing all of the lateral propping – bracing the building against wind loads, to prevent it from twisting – and inserting all of the floor propping, Mabey Hire enabled us to take out the existing lift core. This critical demolition works had to be carried out under new site operating procedures from the UK Government relating to Covid-19, with just a limited number of people on site. We were able to fine tune our procedures – including health and safety monitoring and training up a team as ‘temporary works engineers’ in order to sign off on the works ourselves – meaning when restrictions were eased, we were in a very good position to catch up quickly and safely.
“Mabey Hire’s engineers also designed and provided additional propping to support the front elevation, from basement to roof level, so we could remove and replace the existing front elevation steel columns. Throughout the project, Mabey Hire’s team has been very responsive, and the installation of the temporary works went well.”
