The challenge
A key transportation hub for buses, trains and taxis, Bradford Interchange forms a major part of the city’s transportation network. As such, to create a more welcoming appearance to the area, construction work began to refresh the existing plaza.
However, when planning for these permanent works above ground, it was found that the concrete supports below ground would be overloaded under the loading scenarios proposed. As a result, a propping system would be required to properly support these structures across the course of the works.
Ashley Best, Temporary Works Design Manager from Balfour Beatty, explained: “Our original scope of works was to partially demolish the plaza and backfill the area, before adding new paving, planters, trees and other soft landscaping. Before we could commence, we conducted a structural and condition survey, which flagged up the potential for instability within the bus interchange and triggered the need for a propping scheme. It was here that we reached out to Mabey Hire for its propping expertise.”
Our solution
Russell Ward, Major Projects Sales Manager at Mabey Hire, continued: “Our design scheme for this project utilised our Mass 25, Mass 50 and System 160 propping in combination with our new PERI MULTIPROP solutions.
“Our Mass 50 kit was used for support across the primary beams and main column, Mass 25 for the secondary span beams, MULTIPROP for the tertiary beams and System 160 for the main slab. This ensured complete confidence that, no matter the loads from vehicle traffic above, there would be no risk of damage to the structure. Due to how busy the area was, with high footfall and vehicle traffic, we had to accommodate the potential for emergency vehicles to be above the area we were propping, in the occasion of a fire or other such event. This meant that we had to factor these potential loads into the selected load case scenario we used when designing the scheme.”
The city centre and underground location of the car park presented additional challenges, particularly with regards to getting the required equipment to site, as Ashley explained: “We had to work closely with the local council in terms of coordinating deliveries to site, with all materials having to be delivered early in the morning. It was also essential that the propping equipment was lightweight in nature, as we were limited to three tonne shipments on the main slab at a time. This was one of the reasons we chose to work with Mabey Hire, with its range of lightweight, aluminium solutions, particularly the PERI MULTIPROPs suitability in this regard. Crucially, they were able to meet every loading criteria we had.
“Another challenge we faced was that the car park flooring wasn’t completely level. Fortunately, Mabey Hire was able to adapt to the site conditions, using spreader beams that were grouted into the floor to disperse the load out, ensuring there’d be no shift over the two years of this scheme.
“Due to the presence of mechanical, electrical and HVAC services within the car park, for which there were no drawings prior to arriving onsite, Mabey Hire also had to adjust its propping scheme to accommodate. They did this on the day, with no change in the load capacity of the system following this adjustment.
Our equipment is scheduled to be on site for two years whilst the City of Culture works directly above and around the interchange are completed.
