A specialist team from Glanville Environmental, led by Project Engineer, Ian Noden, was recently deployed to work on a project on Cremyll Street, located in the heart of the busy Stonehouse district of Plymouth.
This proved a challenging project from the outset, as the street is located on a peninsular which is very popular with visitors. The area has limited access and exits roads and also included a one-way system.
The project involved clearing a blocked sewer pipe that lay five metres below the road, and building a new manhole chamber.
The existing manhole chamber, made of random cobbled limestone had failed, causing large stones to fall into the sewer channel, blocking it and causing pollution and smell complaints.
This problem also posed a risk of total collapse endangering the public, traffic and nearby buildings.
To enable access to the sewer channel, create safe working conditions for the on-site Glanville team, and accommodate the installation of the 1.5 metre pre-cast concrete manhole chamber, a five by four-metre-wide hole was dug. This involved excavating 140 tonnes of spoil.
This was achieved using heavy plant and included 13 and eight tonne, 360 mechanical diggers, a six tonne dumber truck and mini-digger.
To ensure there was no ground movement and to safeguard the works team and nearby buildings, substantial shoring was installed.
A building surveyor was also involved to monitor the work and ensure there was no damage caused to any property in the immediate vicinity of the excavations.
Being conscious of the potential for disruption and the potential inconvenience to residents and road users, keeping the traffic flowing was a major priority.
To try and keep traffic disruption to a minimum and create a safe working environment, a three-way traffic management system was put in place to keep the traffic flowing.
This was particularly important as the road closure and diversion would affect a school, the Stonehouse Barracks, the Royal William Yard, a number of shops, cafés, restaurants, a public house, bus and ferry routes.
To maximise the effect of the traffic management system the traffic lights were manually operated between 7am – 7pm, seven days a week.
Prior to the work starting, the Project Engineer and Glanville’s Customer Liaison Officer visited the area on a number of occasions, delivering letters and diversion maps, talking and listening to residents, business owners and other stakeholders.
Customer dialogue continued once the work had started and following comments from local residents, the traffic management system was tweaked, which further improved the traffic flow.
During the length of the project pedestrian access along Cremyll Street was not affected.
Following a concern raised by the military about re-routing their large vehicles through the narrow roads that formed part of the traffic diversion, the project engineer met with the officer responsible for traffic management at the Stonehouse Barracks on Durnford Street and addressed his concerns.
Residents in Cremyll Street also raised concerns about vehicle access to their properties, these concerns were also addressed to everyone’s satisfaction prior to work starting.
In discussion with local business owner’s additional signage was put in place, and a left hand filter lane created, making it easier for customers to access their businesses.
The businesses and residents of the Royal William Yard, a former naval site, were also contacted to explain the project and the diversion route.
Approximately 250 letters were dropped off to local residents and businesses explaining what was going to happen, giving details of the road diversion and contact details for Glanville’s and South West Water.
Being very conscious of the need to minimise disruption and inconvenience a project of this size had the potential to cause, the Glanville team worked six days a week and ensured the project was completed earlier than scheduled.