Gipsy Patch Lane, Bristol, UK, is a main road forming part of a new Cribbs Patchway Metrobus route in South Gloucestershire. As part of an asset assesment programme a few years ago, a CCTV survey showed many defects throughout the length of the surface water culvert at Gipsy Patch Lane. The defective sections ran under the busy carriageway so, as an interim maintenance measure the local authority excavated a section of the road and installed a concrete slab over the pipe to protect it from further deterioration or collapse.
During heavy rainfall over the summer of 2020, the same pipe was found to have suffered structural defects and root ingress through open joints and connecting laterals resulting in localised blockages of up to 90%. A new man-entry survey showed the pipe beneath the concrete slab to be deformed.
Major works were already under way in the area to replace a railway bridge on Gipsy Patch Lane, so South Gloucestershire Council took the opportunity to make improvements to the sewer in conjunction with the Network Rail works to minimise disruption, which was further aided by lighter traffic due to the regulations set in place for the Covid-19 pandemic.
Under the Council’s Climate Resilient Scheme, the task was to find and deliver a suitable solution before opening the road up to traffic and risking a pipe collapse. Two options were considered; first, open-cut to replace the section of pipe or second, trenchless technology to reline the affected pipe with little disruption to the area.
Doug MacKay, Project manager for South Gloucestershire Council consulted with Julian Britton, Critical Sewers Manager, Wessex Water and Matt Durbin Associates (MDA), a specialist confined space and GRP structural relining installer to determine the most efficient and economic technique. As with many suburban roads, Gipsy Patch Lane is laden with many services within the carriageway, so rehabiliatation of the existing pipeline through trenchless installation of 210 m of DN800 structural GRP jacking pipe supplied by Amiblu was decided upon. As the contract was classed as emergency works, subject to time constraints and speed of execution, the use of Amiblu’s GRP pipes meant that MDA was able to remove the need for costly over-pumping and install the pipes in live flows, whilst minimising the work area to a single lane closure for uninterupted access to local businesses.
“Another man-entry GRP culvert relining project completed for an important client, I have to say the service from Amiblu creating a stress free delivery schedule to a short time programme during these tough times was exemplary.” said Matt Durbin, Managing Director of MDA.
During the installation of the intial contracted 210 m, a further 70 m section of the pipe downstream required attention, so MDA undertook the additional works saving additional costs and disruption at a later date.
Amiblu jacking pipes are often utilised in pipe rehabilitation projects such as this as they offer a high compressive strength and, compared with conventional materials, an improved hydraulic coefficient. The hydraulic analysis carried out for Gipsy Patch Lane showed no reduction in hydraulic performance and as the pipes are designed to offer a service life in excess of 150 years with minimal maintenance, the life expectancy of this asset is greatly improved.
Delivery Post Brexit
Inter-Ways Limited is a privately owned, independent, UK based freight forwarding company that has been working in partnership with Amiblu in the UK for a number of years. With its extensive network of experienced operational staff and trusted partners all over the world, Amiblu was confident that the team would manage the transition through Brexit changes to ensure that the first deliveries planned for January 2021 were not hampered by the new legislation.
“All credit goes to the team at Inter-ways, we closed for business at Christmas 2020 and had no idea how if any, the new trade deal would look by the time we returned to work on 4 January. They had everything in place for all eventualities.” said Leon Woods, of Amiblu.
The first truck was loaded by Amiblu of Trollenhagen, Germany on 14 January and delivered to site early on 19 January as planned with two further deliveries the following week, more pipes were delivered to complete the project in early April.
The order was placed in November 2020 without knowing how the Brexit deal was going to affect the contract both financially and on programme as the new customs procedures had not been finalised until late December 2020.
Under the new rules, Amiblu’s customers now become the importer and so the partnership with Inter-ways has proved to be a benefit as they were able to research and put plans in place for all eventualities as nobody knew until late December what the deal would be.
With Inter-ways now appointed as customs agents for MDA, the team at Inter-ways ensured that all paperwork was in place and new procedures managed completely resulting in no hold ups at the port and the deliveries kept to the schedule. In total 4 full loads of pipes for this project have been delivered and all have arrived on time.
“For this project, the Council had concerns about the risk of potential pipe collapse under traffic loading. The fact that road was already under a full closure due to an adjacent project to replace an old railway bridge meant that timing was critical for this project. It was essential that the work had to be completed before the proposed re-opening of the carriageway. Additionally, there was a limit to the funds available through the Climate Resilience budget to complete the scheme. We worked very closely with MDA and our designers to review the site constraints, risks to programme delivery and budget constraints to determine the most appropriate remedial solution. I was grateful for the time, input and patience spent by MDA during this period to explain the construction process and provide answers to all our questions and concerns in advance of making the final decision on the preferred option. Once the decision was made to proceed with the GRP option the process was relatively straight-forward and stress-free from the Council side of things. In the main, this was down to the excellent communication, planning and execution of the works by MDA. Both projects were completed on-time, within budget and with minimal disruption to the public and businesses that rely on using Gipsy Patch Lane.” commented Doug MacKay, Project Manager, South Gloucestershire Council.