Knowing the rules of the road
April 1 was an important date for the utilities. A new regime governing street works came into force. WET News outlines the impacts on the industry, and the evolving range of trenchless techniques to cope with them.
A growing population is using more vehicles to make an ever increasing number of journeys. And hence more sections of the road network are operating above their planned capacity.
Road-building programmes struggle to keep pace with demand, and the pressure is on to keep the roads we do have running as smoothly as possible.
The Traffic Management Act 2004 (TMA), which received Royal Assent in July of that year, contains several measures that are due to be rolled out over the next few years to help keep the UK's road network flowing.
The TMA places a duty on local traffic authorities to expedite the movement of traffic on their roads and they are required to make arrangements for management of the network to comply with this duty.
April 1 2008 was a key date for the TMA and the utilities. On this day, the first phase concerning the notification of street works was introduced. The new regime was the subject of three years of consultation. It sets out a revised system of notification from what was previously in operation under the Roads and Street Works Act.
Under the new system, the following are likely to require notification:
- Breaking up or resurfacing a street
- Opening up the carriageway or cycleway of a traffic-sensitive street at traffic-sensitive times
- A reduction in the number of lanes where there are three or more
- A reduction in carriageway width of a traffic-sensitive street at traffic-sensitive times
- Employing traffic control
- Where there is a temporary traffic regulation order in place or suspension of pedestrian facilities
- Major - 11 days or more
- Standard - four to ten days
- Minor - one to three days
- Immediate - urgent or emergency to prevent or put an end to a loss of service
Also, there are new powers to restrict major road works taking place within five years of its construction or reconstruction, or three years from its resurfacing.
Again, where major works are planned, the traffic authority can determine the times during the day or night when proposed works have to be carried out.
On top of all this, failures by those seeking notices to follow the procedures (including failures to clear the works on time) will incur financial penalties.
For this reason, says Ferro Monk, trenchless technology has an increasingly important role.
The UK has more than 700,000km of mains and sewers serving around 20 million properties. The cost of replacing these physical assets has been estimated to be around £200B, and three quarters of this intricate system is located underground.
Maintaining and adding capacity to this network will bring more challenges in light of the new TMA requirements, with the desire to get on with work potentially being frustrated by the need to comply with the revised notice periods.
Industry organisations such as the National Joint Utilities Group, a body that represents the utilities on street works issues and, the United Kingdom Society for Trenchless Technology recognise the benefits that trenchless technology can offer.
These benefits can include:
- Cost savings, both social and project related
- Time saving
- Reducing environmental impact
In many cases, access will be possible outside the highway using these techniques, preventing the need for notification in the first place. This means that those works can progress without undue delay, without the need to go through the notification procedure and without the risk of incurring penalty notices for non-compliance with the procedures.
In other situations, even though notification may be a requirement - due to the favourable speed of installation, which is a feature of many trenchless techniques - the notice period can be reduced considerably. This enables works to proceed with a reduced lead-in time to other methods.
The range of trenchless techniques continues to grow, as innovative methods are developed, existing ones refined and new materials introduced. Trenchless technologies, in the context of water engineering, can be split into three areas, and include, among others, the following techniques:
- Repair and Rehabilitation - cleaning; localised repair; and full-length lining
- Replacement - pipe bursting / splitting / eating
- New Installation - impact moling; pipe ramming; auger and thrust boring; pipe jacking; micro-tunnelling; and guided boring and directional drilling
The company recently carried out a series of sewer rehabilitations on one of Britain's busiest motorways.
New drainage had been constructed under the new carriageways and connected to the old pipes under the existing, in-use lanes. The old and new pipes were then lined from manholes located in the verge, providing a homogenous, relined pipe running underneath both the new and the existing road.
This particular section of motorway is used by thousands of vehicles daily, and closing it to carry out repairs would cause major disruption. Working closely with the main contractor to co-ordinate the works to fit in with the overall programme, Ferro Monk has installed eight liners of between 225mm and 900mm diameter, over two site visits.
Investigation and planning are key features that help ensure works of this nature are executed without incident. On all projects an initial site survey is done by one of Ferro Monk's rehabilitation managers. This seeks to determine the characteristics of the site, and if any special measures or considerations need to be made.
The condition of the pipe is determined using CCTV and accurate measurements are then taken of the host pipes length and diameter, together with details of the depth and any loadings. All liners are designed and manufactured to suit each individual pipe to be rehabilitated, with the thickness being determined by the preceding design parameters.
Ferro Monk works with one of the world's largest and most respected felt tube/lining (also known as socks) manufacturers. Also based in West Yorkshire, it supplies tailor-made liners to Ferro Monk's processing facility in its factory on the outskirts of Leeds.
From this central-UK location, the liners, now impregnated with a mix containing resins and catalysts, are transported to site. Installation is usually completed over one or two days. Any lateral connections that were pre-logged during the initial CCTV survey are reopened using robotic cutters. These are operated remotely also using high-quality CCTV.
As an alternative to full-length lining, where there is no need to rehabilitate the whole pipe, isolated sections can be repaired using patch liners.
Beyond these remote methods, the company is also kept increasingly busy using its Ferrocement lining system. For use in structures where man-entry is possible, this provides an alternative to GRP and similar prefabricated methods. It takes and follows the shape of the existing structure, which results in a lower loss of cross-sectional area when compared with other systems.