Slipform at One City Park

A new state-of-the-art office complex benefited from the Doka Slipform system in Bradford, Yorkshire.

Challenge:

• rapid core construction required to enable steel frame to follow
• productivity requirements
• exacting tolerances demanded
• city centre location

The Slipform system’s hydraulic technology allows the concreting of monolithic structures to be completed more rapidly and cost-effectively than traditional formwork methods for certain types of structure. This was the case at One City Park, which is being delivered by nationwide placemaker, Muse, in partnership with Bradford Council and main contractor Caddick Construction, a new steel-frame development in the heart of the city where Doka’s Slipform system created the building’s concrete cores.

With a 5,240m2 footprint, One City Park’s striking five-storey steel and glass structure is designed to attract local and international business to the city centre. The BREEAM ‘Excellent’ building is a product of government, West Yorkshire Combined Authority and Bradford Council funding. The project, which is also designed to raise Bradford’s profile as a ‘destination city’, is one of a number of major capital development projects in the district which was recently named UK City of Culture 2025. It is the first new high quality office scheme to be delivered in Bradford city centre for 20 years.

For the Bradford development, Doka, working in conjunction with Howard Civil Engineering, ensured the Slipform system was an equal success when erecting One City Park’s central concrete lift and stairwell cores. The smart hydraulic solution was intrinsic to the monolithic structures’ safe, rapid delivery as it allowed concreting to continue all day, every day. The self-raising mechanism uses hydraulic jacks to climb upwards, facilitating rises of approximately 30cm per hour when operating with all working platforms raising without a crane. The Slipform process negates the need for structural through-ties. Hence, key building elements can be completed safely and at exceptional speed.

Set up and operating from the building’s ground level, Slipform’s assembly was carried out and managed by Doka’s Slipform Supervisor, Arthur Postl, who started on site approximately two weeks prior to core construction work starting. The Slipform system from Doka is adaptable to individual project requirements, but in this instance, there were three platform levels included. Firstly, there was an inset upper storage platform, which also allowed crane access to the main working platform for the supply of building materials such as rebar and other products. For this particular core the inset upper platform allowed easy crane access for large embedded steel plates to be installed. Secondly, there was a main working, control and pouring platform and thirdly, a lower platform to facilitate any finishing requirements for the concrete.

Speaking of the Slipform system’s use on the One City Park development, Paul McGarry, Contracts Manager at Howard Civil Engineering said: “Doka’s excellent Slipform system ensured the concrete core’s quick and easy completion. We were grateful for the company’s excellent technical support during this vital project stage. Indeed, we enjoyed a very easy working relationship with Doka throughout the concrete core’s construction, with a lot of communication between Doka and ourselves to make sure the process was carried out as smoothly and safely as possible. It was the first time Doka’s Slipform system had been used on a UK project, which made this programme extra special for all involved. We look forward to working with Doka on other building projects in the near future.”

Andy Smith, Project Director at Muse, added: “The opportunity to harness new technologies and systems like Slipform, alongside the skills and specialist knowledge or our extraordinary build team, will enable us to deliver this landmark scheme for the city on time with building work due to complete this summer. One City Park will combine high-quality specifications, flexible floor plates and strong sustainability credentials to attract the type of fast-growth businesses that will really enhance job opportunities for the district.”

Doka’s Slipform system spent 14 working days on site carrying out One City Park’s concrete cores, which were completed on time, to budget and with accurate tolerances of just +/- 7 mm at the completion of the concrete cores. Its rapid, high-performance capability means this exceptional city centre development remains on track for building work to complete in summer 2023.

The all-round service provision included planning, engineering and specification guidance, with its experts available to monitor its system’s effective use on site. Indeed, for the One City Park project, Doka’s expert instructor was on site to oversee the Slipform system’s successful deployment. In addition, the instructor was able to provide guidance on performance improvements such as concrete mix selection depending on inclement weather conditions and rig performance for the duration of the project.

For One City Park’s core, the Slipform rig was fully-enclosed using Doka’s Xbright mesh panels as required by the customer. For complete enclosure, however, Doka can also offer their Xbright pc (polycarbonate) panels which have the additional benefit of reducing the decibels of noise pollution escaping from the core.