The Omni Centre car park is an underground structure comprising 4 levels and opened in 2002. The parking decks to Levels -1 to -4 showed signs of disrepair from the ingress of de-icing salts from traffic using the shopping and entertainment complex above with failure from uncontrolled previous repairs.

Following extensive condition surveying by the consulting team, a corrosion management scheme was designed to provide long-term control of corrosion.

The variation in current condition meant that a mixed solution approach was taken that saw the use of ICCP to the most active areas (Levels -2 full and half f Level -3), targeted use of galvanic anodes within repair areas and full deck use of surface-applied corrosion inhibitors (Level -1, -4 and the remaining half of Level -3). This provided technical solutions balanced by the most economic approach to corrosion mitigation.

The ICCP system used an optimised, low carbon approach with respect to the materials used and preservation of embodied carbon through targeted and minimised repair, dovetailed with online control systems for the whole life protection of the facility.

Product / System Used

LoCem® +chase® ICCP system, C-Puck® III galvanic anodes and Sika Ferrogard 903 SACI with AchillesICP, AchillesGCP and AchillesIES interoperable network management systems and AiMS online management facility.

All decks were completed with a Triflex waterproof membrane for performance and aesthetic finish.

Project Details

This system comprised of 42 ICCP zones and 7 additional monitoring zones for levels protected using galvanic anodes and surface-applied corrosion inhibitors. ICCP was adopted where existing high corrosion risk was most prevalent along with high chloride concentrations within the concrete cover. This strategy was adopted to ramps and decks at Level -2 and 50% of Level -3. For Levels -1 and -4 where pre-existing risk was less then, concrete repairs were protected with 6000 galvanic anodes (GCP) with the remaining deck areas receiving surface-applied corrosion inhibitor. All decks and ramps were also coated with a waterproofing membrane.

All the anodes and monitoring could be controlled and data accessed remotely throughout the car park helping to extend its service life for 100+ years.

Project Impact

This ESG compliant approach meant there was no need for demolition or extensive reconstruction using new materials, helping to reduce waste and harmful emissions. Reconstruction was also a near-impossible strategy due to underground facility and electric tram on land, meaning something non-invasive like cathodic protection was essential to minimise social disruption.

Awards

British Construction Industry Awards (Shortlist) – Environment and Sustainability Initiative (2023)