Optera received a call from our Insurer client in 2016, following the collapse of a timber crib wall in Teignmouth. The wall had failed nine years after construction due to a build-up of hydrostatic pressure behind the wall and the onset of rot of the timber elements caused by a leak in the surface water drainage behind the wall.
The location of the site and the terraced site was the major logistical difficulty which plant and materials required to access the site from a narrow private lane to the rear.
The Optera Solution
Optera have been involved since day 1, carrying out the site investigations to determine causation and in the design process.It was a stipulation of the client that the wall be reinstated on a like for like basis so we set about designing a suitably robust crib wall to combat the imposed loads. It was also necessary to remove the crib wall and create stable ground behind to allow us to reconstruct the wall.
This was achieved by removing the wall and installing Macmat R and platipus ground anchors into the garden.
Existing surface water drains have been repaired and the existing footing grubbed out. The client expressed concern about the possibility of a slip failure of the slower slope and consequently, Optera designed a piled raft using grundomat driven steel cased piles which connected into specialist formwork which allowed the perfect profile of the footing to be created in order that the wall was constructed at the correct angle of repose of 1 in 4.
Furthermore the new wall is constructed with a perforated land drain at the base of the wall to collect and convey any ground water through the wall and away from the new structure. Once completed, we have been able to commence the construction of the timber crib and filling with stone. Works are progressing at pace and the wall is now approximately one metre from finished level.
Once completed, we will reinstate the customer’s garden, leaving the site clean and tidy. Another challenging site and technically demanding project completed successfully by Optera Ltd.
Take a look at some other recent case studies that may interest you
The case studies presented below show just a few of the recent projects Optera have worked on.