Project Brief
We were approached by Rider Levett Bucknall (RLB) to provide structural advice on RAAC panels identified in the roof of the Media Hub on the University of Hull’s campus. We were already working for, and continue to work with, RLB completing structural surveys under the Sheffield City Council Framework. We are accustomed to conducting planned and reactive structural surveys on restricted, occupied sites, and delivering design services with minimal disruption.
Solution
We attended campus at short notice to complete a detailed survey/investigation and establish the condition of the RAAC panels. Our initial visual inspection checked for obvious signs of deterioration or deformation, as per Government guidance.
The most notable risk with RAAC planks is their potential for sudden shear failure. We performed a Risk Assessment to identify areas requiring urgent attention, and to check for additional risks, including:
- Unknown services – we reviewed all drawings and information on the building to confirm the location of services and reduce any risk of accidental damage
- Uncovering unknown issues – despite reviewing surveys, encountering unlogged alterations/repairs or structural problems remains possible at any point
- Encountering dangerous materials/contaminants – during all survey work we remain vigilant for unexpected hazards such as unidentified asbestos
- Safety of site users – we advised on immediate mitigation measures required to ensure safe conditions for further surveys, including removal of University apparatus in the affected rooms, and to undertake the design of remediation works
We advised RLB on our findings within an urgent time frame via an emailed report outlining the necessary remedial actions, and provided advice from best practice guidance, including IStructE’s current RAAC guidelines. Our report contained:
- Individual room defects plans indicating all areas of concern and classifying critical, high, medium or low risk conditions for each area. We highlighted water ingress, visible rebar, and potentially unsupported or unsafe structural amendments to existing planks e.g. holes for services
- Protection plan indicating which areas needed propping prior to access by University staff, and designating areas unaffected by RAAC
- Individual room propping plans indicating span directions, anticipated loads, and location of props
We collaborated with RLB’s temporary works contractor to develop the methodology for prop installation, proposing design principles that met the client’s brief. The Media Hub was closed off during the propping works. To allow omission of the temporary props and use of the rooms, we designed a semi-permanent support solution with steel beams spanning load-bearing structure, and timber joists at close centres spanning between the steel beams.
We were further instructed to assess the discovery of RAAC panels in the roofs of three built structures housing plant equipment. As these were in use, it was a challenge to develop a support system for the RAAC. We designed temporary propping plans to thread through and avoid existing plant, whilst maintaining maintenance access. This enabled the University to monitor the planks for six months.
We have retained an ongoing role helping the University evaluate solutions for their RAAC and will support them with full replacement to suit their Capital Works programme.
“We were very pleased with the work Adept carried out on the RAAC surveys at the University of Hull, including the Media Centre and other ancillary buildings. They were responsive, able to attend site promptly when required, and delivered detailed reports within the agreed deadlines. Their professionalism and reliability made the whole process straightforward. We’d happily work with them again.”
Chris Phoenix – Ryder Levett Bucknall
