Formwork & Falsework International Vol 2 No 1
Super Mega Brace for its first major project
Groundforce Shorco has used its new Super Mega Brace support system with integral hydraulic rams for the first time on a major project for the renewable energy sector.
The equipment was supplied to main contractor, Clugston Construction, for use in the construction of a concrete energy-from-waste fuel bunker situated on the Wilton International waste-to-energy site in Redcar, Teesside UK.
Clugston, together with process partner, CNIM, is building the new plant which, when completed, will burn domestic waste supplied by Merseyside Waste as fuel to generate energy.
The imported waste will be transported by train and stored in a huge concrete bunker prior to being burned to generate heat and power.
Construction of this concrete bunker has required the excavation of a 13 m deep box structure below ground level. The completed bunker is 50 m long and 20 m wide.
The walls of this bunker are lined with a series of contiguous concrete bored piles installed by specialist contractor, P J Edwards, with foundation design by engineer Byrne Looby.
Supporting these piled walls at such a depth has required a very strong and rigid temporary propping solution supplied by Groundforce’s major projects division.
Clugston’s chief engineer Ray Postolowsky said:
Until you’ve cast the reinforced concrete base slab, there’s a risk of the bottom of the piles ‘kicking in’ under the pressure of the ground behind them.
So to prevent this happening, Groundforce provided temporary propping at the base of the excavation and another level of support higher up to satisfy the high deflection and stiffness requirements calculated by Clugston’s consulting engineer, Tata Steel Projects.
The upper level of the excavation is supported by two MP500 hydraulic props which are attached directly to the face of the concrete capping beam – a massive structure which is up to 5 m thick in places.
The lower level was supported by three more MP500s which span across the width of the box, and four MP250 knee-braces, one spanning each corner of the rectangular excavation.
All of the props in the lower level bear against Groundforce’s Super Mega Brace beams which transfer the loads from the contiguous concrete piled retaining wall.
So the lower level props can be removed when the base slab has been cast and the high level props can be removed when a bunker dividing wall has been constructed.
Strongest Brace in the Industry
The Super Mega Brace is the strongest proprietary hydraulic brace in the industry. The modular hydraulic components are quick to assemble and lift into place.
This project was designed by Tata Steel Projects and is one of the first fully Eurocode-compliant schemes that Groundforce’s Major Projects department has worked on.
Stiffness was a key factor in the design and so, rather than keep the props under hydraulic pressure, Groundforce was required to lock them off mechanically to ensure rigidity in the frame.
Specially-designed welded isolation plates were used to isolate the hydraulic element of the MP250 props, though not the larger MP500s.