Project Outline:

The Gateway Linear Park (GLP) is the green gateway to Cardiff’s ‘garden city for the 21st century’, Plasdŵr. Situated in the Groeswen neighbourhood of Plasdŵr, the scheme incorporates wide tree-lined avenues and green space to link residents and the surrounding communities to some of Plasdŵr’s key features. These include the main commercial centre, Canol Plasdŵr / Plasdŵr Centre, residential areas, and Plasdwr’s first primary school.

Walters are engaged via an NEC3 Professional Services Contract to complete Early Contractor Involvement on the scheme in May 2021 after setting up effective collaborative working practices on the Section 278 Junction 2-5 works that were already underway.

Following the ECI contract, Walters were engaged as Main Contractor for the GLP scheme in August 2022, on a NEC3 Option A contract.

The GLP includes a 350m length of Section 38 adoptable highway to the south of the Llantrisant Road/Heol Isaf junction, extending into the Plasdŵr site which was designed by Arup. In addition, the works include hard and soft landscaping to attenuation basins servicing the highway and wider Plasdŵr development which was designed by Pegasus. The works include, but are not limited to:

• Site clearance
• New pavement construction including speed tables, road markings and signage
• 3 priority junctions
• Footway/cycleways running the length of the works including two signalised pedestrian and cycle crossings
• Design and build footbridge
• Utility installations and diversions in liaison with utility providers including new potable water mains and 11kv cabling, in addition to RC protection slabs over an existing high-pressure gas main
• New Drainage, including swales and attenuation basins as well as adjustments to existing drainage features
• Adoptable and private street lighting
• Bus shelter installation
• Utilities and utility provision to service the wider site and land safeguarding for future trunk watermain diversion
• Dŵr Cymru Welsh Water (DCWW) adoptable S104 foul and surface water drainage
• Hard and soft landscaping works to Ponds B, C and D and adjacent areas including high specification soiling and seeding, 6 play equipment areas and extensive planting

Project Delivery: -

We sequenced the early phase of the programme to make use of the remaining, but short, favourable weather window in 2021 to partially excavate permanent works ponds on the north of the scheme. The drainage catchment fell north-west to south-east so sequencing the works in this way afforded Walters the opportunity to use these ponds throughout the wet autumn and winter seasons to aid in surface water management.

An existing Wales and West Utilities (WWU) high-pressure gas main ran through the centre of the site east to west, essentially dissecting the project into two work areas at the start of the project. To mitigate delays in starting the works, Walters completed extensive pre-construction liaison with WWU to design and plan the installation of temporary gas main crossing points that allowed initial pond earthworks to commence as described above. WWU were impressed with our proactive management of these works, which ultimately allowed the approval of  RAMS and supply of WWU supervisors for watching briefs in line with our tight programme dates. A similar approach was adopted for the management of works in the vicinity of existing Western Power Distribution (WPD) owned 132kV overhead cables.

Walters drafted bespoke sketches that proposed where temporary road markings and street lighting where required for a combined shared access to other parts of the scheme. All of which were adopted into the Road Safety Assessment Report and instructed by the Employer. Reliable and fit for purpose access for all stakeholders was achieved throughout the project in challenging and changing circumstances.

Added Value and Client Partnerships: -

Further to commencing this scheme and building on the pro-active and collaborative partnership built on the Jct 2-5 and GLP contracts, Walters are now the Contractor of choice which has culminated with the implementation of an NEC Framework Contract agreement for the next 8 years of the development. Our new role has evolved and we provide expertise in the following areas:-

• Buildability Design Review
  • Consider the design as presented by the design team and outline any technical and or practical issues, itemise these and report them back to the design team.
  • In addition, Walters were asked to highlight any ambiguities and inconsistencies that would prevent the works being undertaken as per the current design, such as incorrect construction details and design clashes between separate design packs.
• Aiding in the Planning and Co-ordination of the Utility Designs
  • Establishment of a utility schedule to identify all associated actions related to services on the project. This schedule included the capability to track the status of supply and diversion initial designs, receipt of quotations from Statutory Providers, quotation payment status and final design agreement.
  • Walters also took on the responsibility of identifying trial pit requirements based on information available in order to confirm locations of services and undertook these works prior to site mobilisation to allow adequate time for exact line and level to be incorporated into the design
  • Walters also liaised with service providers to confirm exact positions of various services along with approval for excavating over or near to their apparatus, including incorporation of a Statutory Authority watching briefs into the programme.
  • Walters reviewed the Works Information provided to identify any procurement issues and where relevant reported these back to the design team with mitigation measures.
• Wholistic Risk Management and Risk Register Collation
  • Implement to approaches and initiatives from the ICE’s ‘Project 13’ delivery strategy.
  • Walters liaised with Principal Designer in our role as Principal Contractor to identify and mitigate major Health and Safety risks
  • All risks were tabulated by Walters into a project risk register that communicated the risk, risk owner, mitigation measures available, risk score, commercial impact, effect on programme and RAG rating for the risk.
• Programme Optioneering
  • The Employer had several constraints linked to access and sectional handover on this project but also areas of missing design information. Walters were required to stress test works sequencing options to provide an optimal programme duration, manage existing access constraints and meet sectional handover deadlines, whilst also giving the Employer as much time as possible to obtain outstanding design information. Walters and the Employer then held programme workshops to agree the best programme option for the Employer and the project.

The Walters team collaborated closely with the Employer’s NEC Supervisors and the Cardiff City Council Supervising Engineer to ensure a high-quality finish in line with their requirements, minimise defects and advise on value engineering opportunities to reduce the overall cost of the project. These included the use of a more sustainable recycled tyre resin bonded footpath surfacing material and replacement of Scottish sourced pond basin pebbles with locally sourced pipe bedding.