Queen Victoria Street - One Buildings



Location: London

Client: Bowmer and Kirkland

Scope: Design and Install FRP Strengthening

99-101 Queen Victoria Street is a high quality office development in London. The superstructure comprises 250mm thick post-tensioned slabs. During fit-out, one of the sub-contractors cored through a tendon and Structural Systems were called in to advise on remedial measures. A design check confirmed that strengthening would be needed as the hole had been cored too close to the mid point of the longest span.

Structural Systems designed and installed a plate bonding solution comprising 5No carbon fibre strips on the soffit and 2No steel strips on the top. The advantage of the carbon fibre was its low weight, it easily adhered to the resin once applied to the soffit and did not require holding in position while the resin cured. The top plates were needed to resist long term compressive creep of the concrete in order to limit deflections. Hence steel strips were selected as they provided the necessary cross sectional area and stiffness more compactly.

The carbon fibre strips were MBT's MBrace low modulus 150/2000 laminate, 100mm wide by 1.2mm thick. The steel strips were 200mm wide by 8mm thick mild steel. Both were bonded with epoxy adhesive having first removed the laitance from the concrete and primed the surface.