Big Yellow have recently opened the extension to their Wandsworth store which sits beside the River Wandle. The extension is located over large twin culverts that serve as a bypass for the river in times of high flow. The 3m x 3m culverts form part of the original development built in the late 1980’s and are of pre- cast reinforced concrete construction.
CampbellReith was commissioned by Big Yellow to organise the survey works, obtain any necessary permissions from the Environment Agency associated with working on or near to a main river, review and analyse the survey information and prepare the scope of the remedial works. The Wandle was noted as being a salmonid river and as such no works were permitted in the culverts between October and March.
The survey revealed that the culverts were in a good condition with the majority of defects relating to the sealing of the joints between the pre cast segments so no further intrusive or structural surveys were needed, much to the relief of our client. The base of the culvert could not be surveyed during the original works as there was low level river flow in the channel so when the project was on site and more resources available, the culverts were individually dammed to allow the survey to be completed.
Following all the surveys CampbellReith scheduled the remedial works identifying the defective joints which required replacement and a specification for the works, with approximately 400 metres of new sealing required.
The contractor subsequently carried out the repairs successfully and a record of the works was submitted to the relevant authorities.
The presence of the culverts beneath the extension footprint also constrained the position of piles and foundations for the structural frame with a limited depth for any ground floor transfer structure above the culverts.
No salmon were spotted during the works!
Photo courtesy of Mountford Piggot Architects