The Problem
Optera were called by the insurer following the collapse of a timber crib wall in a difficult-to-access, terraced site in Teignmouth. Optera’s site investigation team established that the wall had failed nine years after its initial construction due to a build-up of water pressure behind the wall and the onset of rot to the timber elements caused by a leak in the surface water drainage behind the wall. Access to the site was logistically difficult and was only possible from a narrow private lane to the rear.

The Optera Solution
The client stipulated that the wall should be reinstated on a like-for-like basis, so we set about designing a suitably robust new crib wall to withstand the imposed loads. The new design included a piled raft foundation, using driven steel cased piles to provide additional support at the foot of the wall, as well as a perforated land drain to collect and convey any ground water through the wall and away from the new structure. Ground anchors and geotextiles were incorporated in the design to provide added stability to the retained earth.

Project Conclusion
The new crib wall was constructed from the ground up with stone fill behind. The client’s garden was reinstated leaving the site clean and tidy. Another technically demanding project completed successfully by Optera.

“Access to the site was logistically difficult and could only be gained from a narrow private lane to the rear.”

View or download PDF file