A Lateral Approach from IWJS Achieved a Solution for Thames Water
Thames Water was presented with what seemed to be an insurmountable and potentially extremely expensive sewer clearance problem. However a solution was found to be at hand, courtesy of IWJS, when they took over this new challenge for major client Thames.
The serviceability of the sewer located at Waterloo in London had become severely affected by 8 cubic metres of C40 high strength, heavy construction grade cement. This challenging situation seemed a thorny problem that could have presented enormous civil engineering costs potentially for the client and caused major disruption. Especially as the sewer was located within a highly busy central London urban area, therefore it was difficult to rectify the problem without affecting traffic flows adversely for prolonged periods.
IWJS was therefore tasked by Thames to come up with a more creative, cost effective solution, without resorting to a radical and hugely expensive civil engineering intervention. Following a comprehensive survey of the sewer initially by IWJS, to ascertain the full extent of the problem, a full sewer clean was then scheduled. This would follow after the careful removal of the concrete and silt from the 1.2 metres elliptical profile sewer approximately 160 metres in total length.
The Challenge Ahead
Presented with the task, IWJS examined the problem thoroughly from an open perspective that required lateral thought and ingenuity to arrive at a workable solution. A uniquely creative approach was proposed by IWJS, working collaboratively with civil engineering partners, as this was found to be the best way forward, to achieve a cost effective solution. Thames Water therefore commissioned IWJS to head up and carry out the project.
IWJS acted as the principal contractor working alongside First Intervention Team (F.I.T) and major civil engineering partners Amey and McAllister.
Early planning meetings took place to orchestrate the smooth delivery of the project and minimalise any disruption to the area. With essential traffic management being arranged to provide a temporary bus stop suspension and pavement closure within 2 metres of the curbside. Due to the busy central urban area, much night working had to be employed to deliver the project with as little impact as possible.
The adopted plan was for the McAllister crews to enter in the upstream manhole outside a public house. There inserting bungs to stop the flow, enabling the Amey mining crew to enter at the downstream manhole to drill out the offending concrete from the line. IWJS positioned a tanker adjacent to the upstream manhole strategically, to control the flows safely around the clock, enabling the work to continue unimpeded for the teams working below in the sewer.
Obstacles to Overcome
However, upon closer inspection the McAllister teams were unable to insert the bungs, due to excessive silt constricting the line. IWJS then carried out a line clean of approximately 130 metres downstream to remove the silt effectively, thus allowing this essential operation to proceed smoothly as planned.
The McAllister team was then able to enter the manhole to insert the bungs and inflate them. Once these were in position and inflated, the Amey mining team was then able to enter the manhole downstream to commence drilling and secure removal of the concrete. With the rescue team (F.I.T.) on hand for all entries into the manholes to ensure maximum safety at all times.
A Positive Outcome
The safe removal of the highly tough concrete proved to be a laboriously slow process. However, once all of the concrete had been removed from the sewer successfully, IWJS was then able to carry out a full clean and provided a further monitoring survey to ensure the line was completely free. The end result of this challenging project, to restore the compromised sewer back to a free flowing line, was achieved effectively. Thames Water was highly delighted with the outstanding results attained, with minimal cost and disruption to their services and the area.
With the mission being fully accomplished, Thames gratefully acknowledged IWJS for their professionalism and skill in managing such a challenging and difficult project.