Arch Henderson was appointed to undertake design for the construction of a new Ro-Ro jetty structure for Dublin Port Company as part of the multi-million pound redevelopment of Alexandra Basin. This project has been shortlisted for 'Engineering Project of the Year' at the Engineers Ireland Excellence Awards 2019.
Video Courtesy of Keating Construction
The new jetty provides berthing for two new linkspans and includes all ancillaries to allow effective operation of the facility servicing some of the world’s largest short sea Ro-Ro cargo ferries that run between Dublin and continental Europe. Due to the new jetty being located adjacent an existing operational Ro-Ro facility, careful collaboration with the contractor and Port was required so that the existing facility could remain operational throughout the works. Through this collaboration, Arch Henderson was able to understand the contractors preferred method of construction and we could tailor the design to suit this and the Port’s operational requirements.
The completed jetty structure is approximately 290m long, provides two new berths comprising nine individual reinforced concrete dolphin pile caps supported on vertical tubular steel bearing piles. The design team was also responsible for design of guide piles to align one new floating linkspan as supplied by Ravestein BV and one relocated linkspan. To ensure a suitable solution was developed, which met Dublin Port Company’s requirements and suited the contractors preferred construction method, required extensive collaboration with the contractor and our design partners with careful consideration of the geotechnical conditions present versus the berthing and mooring requirements. This lead to an innovative ‘flexible’ dolphin solution involving vertical tubular piles supporting a reinforced concrete pile cap and allowed us to meet the Port’s onerous loading conditions and range of vessels whilst still adopting the contractor’s method of preferred construction.
Access to the dolphins is by a series of nine interconnecting walkways. These take the form of lattice girder structures prefabricated from steel sections and lifted into place with services for each dolphin suspended beneath. Due to the nature of the ‘flexible’ dolphins, all walkways were designed to accommodate the range of movement in the dolphin structures. This was achieved by designing a pivot connection at one end and a sliding bearing at the other.
Arch Henderson was responsible for fully developing all aspects of Dublin Port Company’s initial design brief for a new Ro-Ro jetty. This included, but was not limited to, geotechnical design, mooring and berthing design, structural design, utility design and mechanical and electrical design. Arch Henderson also provided full construction drawings, specifications and 3D BIM model as part of the contract.
