The Chiswick flyover is a short, elevated section of the M4 motorway in the western approaches to London. As with all of our bridges in the UK, the continuous use of de-icing salts on the road above has taken its toll, with large areas of the exposed concrete areas on the bridge exhibiting signs of spalling.

In July 2021 a Special Inspection survey of the structure was carried out consisting of a delamination survey, concrete testing, and a visual inspection. In early 2022 CRL were called in by Octavius to look at the structure and submit a price for the repair works required. Unfortunately, due the location of the bridge and the difficulty of organising traffic management, the project stalled for a while, and it was only in March this year that we were awarded the contract to carry out the works.

The works consist of concrete repairs (spray applied with Webercem DS) to all spalling areas on the piers and cross beams (approx. 4m3), installation of CPT’s DuoGuard 145 Patch anodes (approx. 250no.) and the removal of all rust and the cleaning and greasing of the bearings.

The initial contract award value was £275k with a programme period of 9 weeks. The number of repairs has increased slightly though with the final estimated contract value now expected to be in the region of £320k. The works are being carried out under NEC4 Option C.
Chiswick Flyover Concrete Repairs
Michael Balletta
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