Highway Management Construction (HMC)
Contractors in Ireland increasingly source as many product lines as possible from a single supplier. That trend is clearly illustrated in AG’s success in winning major orders for four separate products for the £104 million Design, Build, Finance and Operate (DBFO) contract for the upgrade of Northern Ireland’s Westlink and M1.
Through a mix of product innovation and development as well as acquisition, the company has greatly expanded its product range in recent years. Today it claims to manufacture the widest range of construction products in Ireland.
AG supplied 20 miles of half batter road kerbs and a significant number of manhole units in a variety of depths and diameters for the Westlink contract. The project was undertaken for the Northern Ireland Department for Regional Development’s Road Service by main contractor, Highway Management Construction (HMC).
The County Tyrone firm also won a major order to supply more than 8,000m2 of its Alphacrete® Masonry Block for cladding at bridges. The block’s rugged riven-faced natural stone appearance was chosen as a more aesthetically pleasing alternative to concrete.
What makes the M1/Westlink project particularly significant for AG is the fact that it represents the first time in the UK and Ireland that its Anchor Landmark retaining wall product was used in a major road infrastructure project. Anchor Landmark has full BBA Roads and Bridges approval.
It was in the early planning stages of the Westlink project that HMC – a joint venture involving John Graham (Dromore) Limited, Northstone (NI) Ltd (formerly Farrans Ltd) and Bilfinger Berger AG – decided to incorporate a reinforced earth structure. Lead project designer Arup then worked with Maccaferri Ltd – AG’s engineering partner, and sole distributor of the Anchor system – to come up with the Anchor Landmark solution.
Work was completed on the retaining walls at the Stockman’s Lane junction in south Belfast where the motorway was widened through the construction of two new bridges. Three walls have been built at the junction’s city-bound on and off slip roads and the country-bound off slip. The structures have been designed to hold up widened and heightened embankments while at the same time maintaining the original height of the existing slip roads.
Each is approximately 150 metres in length and up to 4 metres tall. A further wall was then built on the country-bound on slip once the new bridge was completed.
The retaining walls were designed with the specific purpose of addressing two key issues.
Firstly, speed of construction was vital because the project is located on a main arterial route and most of the work involved had to be undertaken at night. Secondly, ground works on the congested site had to be kept to a minimum so that the existing slip roads could be kept open during the widening scheme.
An additional factor in the product’s selection is the attractive range of colours available and the split face texture which complements the scheme’s overall aesthetic qualities.
The choice of the Anchor segmental retaining wall system means that the excavation work required to build it was kept to a minimum. A 250mm deep trench filled with a layer of compacted stone was all that was needed as a foundation in each of the three completed walls.
Behind the walls, a strip just 3.5 metres wide was excavated to accommodate Enkagrid Pro geosynthetic reinforcement and backfill which work together with the Landmark facing blocks to form a highly efficient engineered retaining wall.
On site supervision was provided by AG and Maccaferri’s technical support team to ensure HMC staff were fully conversant with the system and the construction details. Regular site checks were carried out by the technical team as the job progressed and HMC staff responsible for building the walls were able to complete sections of up to 30m2 in a single day using a five man squad.
According to AG’s retaining wall sales manager, Philip Dilworth, the use of Anchor in the Westlink has attracted a lot of interest from construction industry firms throughout the UK and Ireland – and opened up new opportunities.
“Anchor Landmark holds BBA Roads & Bridges accreditation and was approved by Northern Ireland’s Road Service for use in structures requiring TAS approval.
“Its speed of installation and associated cost savings make it a very attractive product for the large number of infrastructure projects currently underway throughout these islands.
“It is a high quality product which has helped to further enhance our reputation within the industry as a reliable supplier. There is no question that it has helped to open doors for additional contracts on projects such as the Westlink/M1 job.
“It clearly makes sense for contractors to buy in a wider range of products from companies with a proven track record for quality, reliability and the ability to deliver.”
“That was one of the main reasons for our acquisition of the Finlay Breton business from Readymix plc which extended our product range even further,” he adds.
Artist’s impression of Stockman’s Lane roundabout by kind permission of Roads Service