Greatham Beck runs through a culverted 5m diameter Victorian brickwork arch structure with a Network Rail track over the top.
Following a structural examination, it was recommended that strengthening works were undertaken. The river running through the culvert was tidally influenced and a dry working area was required. The client originally specified the use of a cofferdam which would have required 24-hour pumping operations using diesel generators.
We proposed using a portadam and over pumping system which allowed tidal waters to flow through the working area whilst being contained within the pipework, bypassing the construction area. This option provided the client with cost savings and reduced carbon footprint by removing the need for generators. Once the dry working zone was created, we cleaned the brickwork and removed all traces of vegetation, moss and water staining, raked out joints and repointed them, undertook brickwork repairs and replacement, installed a reno mattress and gabion baskets, constructed the internal lining of the culvert using formwork, reinforcement and concrete and upgraded the access track and footpath.