The London Borough of Camden commissioned Tempo-PCE to strengthen and waterproof sections, totalling 186m, of Service Tunnel 001 in the period from January 2009 to January 2011.
Roughton UK Limited, the consulting engineers on this project, also independently produced a principal inspection report for Tunnel 001 that was issued in 2002. This resulted in the majority of the two brick ring section being rated at 17 tonne live load capacity. Therefore, the particular objective of the commission was to form a link between the presumed existing concrete saddle and the tunnels’ brick rings. If a link could be proven between the concrete and the brick rings, Roughton’s would be able to confirm from the thicker arch section a live load capacity of 40 to 44 tonnes gross vehicle weight (gvw)
The 40/44-ton live load capacity was reached – and in some areas substantially exceeded – for the sections of the tunnel that were injected. The existing concrete saddle over the brick rings was, in parts, just rubble and required additional quantities of injection material to reconstitute the saddle. Other areas were repaired and any fissures filled. Visual checks of the injected sections showed a reduction of water ingress and surface dampness. Pre and post grouting core analysis succeeded in validating the works.