Carbon Fibre Strengthening
Queen Mary’s Gate, London
Client: Telford Homes
Engineer: White Young Green
Frame: Contractor Atlantic
Contract Duration: 1 week
Queen Mary’s Gate was a multi-phase residential development by Telford Homes, consisting of a cluster of 16 blocks of flats constructed on South Woodford High Road in London.
The last phase of construction included a large podium slab which would provide a landscaped access area to the apartments with car parking below. However, due to a late change in the loading requirements, the podium slab had been cast with insufficient reinforcement in just one bay towards the centre of the slab.
We were instructed by the Client to conduct investigations to determine a suitable solution which would enable to slab to achieve the necessary performance criteria. The assessment revealed that the additional strength could be provided by the inclusion of a relatively small amount of fibre reinforced polymer (FRP) plate bonding.
The slab to be strengthened was a 325mm thick reinforced concrete slab, reinforced with H20 bars at 150 centres. Our solution comprised five strips of S&P CFK 200/2000 carbon fibre plates bonded to the soffit of the slab at 900mm centres. Each strip was 6.9m long and went from the centreline of the support at one end to within 100mm of the face of the support beam at the other end of the 7.2m span.
The carbon fibre strips were just 1.4mm thick, meaning they could be installed with minimum disruption, eliminating the risk of noise and dust – ideal for a residential environment.
The works programme was carefully planned, as there was a narrow window of time before the building was to be handed over to the new residents. On site operations were completed in one week and the concrete slab was successfully reinforced.