Project Brief
We were appointed by Fibrwrap CCUK to design the strengthening solutions for key elements within the London Road building.
We provided structural design services for essential works forming part of this major, low-carbon retrofit scheme that redeveloped the University’s London Road building into a modern, fit-for-purpose ‘LSBU Hub.’
At 20,000 sq.m., it was the largest academic building on LSBU’s main campus, but the internal spaces needed reconfiguring and upgrading to improve circulation and accessibility, and create additional, flexible teaching and learning provision. The redesign provides an open-plan library, lecture theatres, fitness facilities, teaching rooms, informal learning spaces, catering for students and staff, and local community facilities.
To help the University fulfil its carbon reduction targets, the multidisciplinary design and construction team adopted an environmentally conscious design strategy. The decision to retain as much of the existing 1970s concrete-framed building as possible saved 65% on embodied carbon, just under half of the 2030 RIBA benchmark targets. However, to enable the retained structural frame to adapt to the revised internal plan, reinforcement was required in many areas to increase its strength and maintain its structural integrity.
Solution
We were appointed by Fibrwrap CCUK to design carbon fibre strengthening solutions that would combat both flexure and shear in multiple sections of the concrete frame. We have established a long-term relationship with Fibrwrap CCUK, having worked extensively with them on previous refurbishment and strengthening schemes. Application of their specialist materials means buildings like this can be repurposed with less disruption, increasing their life span without the need for significant structural/construction works.
We used historical information and strength tests to produce our design information. To provide the most economical service, we developed a detailed calculation spreadsheet to perform full design calculations for the concrete members, including serviceability design and longitudinal debonding checks carried out in accordance with TR55 and EC2.
Strengthening materials made from carbon fibre are extremely thin, lightweight, and versatile, and methods of repair include Carbon Fibre Plate Bonding and Carbon Fibre Wrapping. Wrapping was selected for LSBU, which involves layering sheets of carbon fibre on structural members to increase load-bearing capacity. Our calculations were used by Fibrwrap CCUK to inform the type, positioning, and quantity of carbon fibre material to be applied to the existing ribbed waffle slabs, reinforced concrete beams, and upstands, providing flexural and shear strengthening as required. On completion, the ribbed slabs and other soffits were left exposed and painted to blend in the strengthening material with the rest of the ceilings.
Over 8,000 sq.m. of Tyfo Fibrwrap carbon fibre strengthening systems were installed, making the LSBU Hub the largest carbon fibre strengthening project completed on a building in the UK to date.
This innovative and minimum-impact solution was an essential contribution to meeting the target for low-carbon upgrades throughout every area of the redevelopment. The building services solutions by others were designed to work with the deep downstand beams, solar glare was reduced, ventilation improved, and the façade overclad to increase thermal and sound insulation performance. The finished scheme achieved a BREEAM Very Good rating and was opened to students at the start of the 2022-23 academic year.
