BELFAST HARBOUR

The construction of a 480m long new quay structure and  deep water berth located in the Port of Belfast has required   heavy use of geosynthetics. Ground conditions at a 50-acre   wasteland site at Belfast Harbour were so poor that a major   programme of stabilisation and improvement was required   to allow the construction of a £50m trans-shipment and   storage facility required to support the offshore wind   industry. 

The riverside site which is next to Belfast’s George Best   Airport and close to the City’s Titanic Quarter is the largest   in the Harbour’s 400-year history. The project was part of a   joint venture between Dong Energy and Scottish Power   Renewables to support the construction of the West of   Duddon offshore wind farm. 

Stabilisation and strengthening of the upper ground   formations were needed as the facility was to be used for   the off-lading storage and assembly of huge wind turbine   components. Large tracked cranes were used to move   equipment and materials about the site and at full capacity   imposed extreme loads on the surface. 

The quay wall was constructed using a combi wall of   1600mm diam. 32m long tubes and 22mm sheet piles tied   back and anchor beam supported on 376no. 30m long   raking tubes. The 17,000 sqm quay slab was supported also   by 780no. 750mm dia CFA piles.  

The works included dregging of the new berth and  approaches. This involved the disposal of 500,000m3 of   material to sea with treatment and disposal of some   contaminated material to land. Behind the new quay, there   are 50 acres of hinterland to receive heavy-duty unbound  pavement involving the placement of more than 900,000   sqm of geosynthetics and the import of circa 1,000,000   tonnes of aggregate. 

With this in mind, engineers devised a scheme which   involved surface build-up of up to 2m depth in places using   a combination of site-won fill and over 250,000 tonnes of   imported stone. This was placed in layers over an array of   Maccaferri Paralink®, basal reinforcement high strength   geogrid approximately 1.3m below the finished surface.