Ratoath Road, Realignment and Overbridge Project

Sep 24, 2014

Byrne Looby Partners recently provided design assistance for one of the largest bridge lifts to take place in Ireland in some years. The lift took place at Reilly’s crossing on the Ratoath Road, Dublin on Saturday 6th September.

The Ratoath Road, Realignment and Overbridge Project commenced in June 2013 and will be fully completed in early 2015, closing one of the busiest manually operated rail level crossings on the Iarnród Éireann network. The €9.8 million Iarnród Éireann project has been developed in co-operation with Dublin City Council and is funded by the National Transport Authority.

The bridge span is 70m with a width of 15.4m to outside of the steelwork, with the steel structure manufactured by Horta Coslada in Madrid. The weight of the lift was approximately 323 tonnes comprising approximately 305 tonnes of structural steel work with an additional 18 tonnes of tackle and hook blocks. The weight of the finished bridge shall be approximately 1,620 tonnes including structural steel, structural concrete, pavement, parapets and finishes. 

Byrne Looby assisted BAM, the main contractor on the scheme, in designing the temporary laydown area for the bridge assembly as well as the crane working platform for the lift. The crane was supplied by Sarens Construction and was a 650t Gottwald Ak-912-1 mobile crane.

The laydown area was set up adjacent to the reinforced earth embankment on the west side of the canal. In order to allow for the assembly of the bridge Byrne Looby designed the temporary support pads to accommodate the temporary support frame. The crane working platform involved the design of discrete pads to accommodate the crane outrigger loadings of up to 380 tonnes. The soft ground conditions and presence of sensitive services in the area required significant coordination between BAM, Byrne Looby and Horta Coslada.

The new bridge will, in tandem with other planned projects, allow for future increased capacity on the rail line for train services.  It will also eliminate major road congestion at the crossing, with 107 trains passing through the level crossing each day, including up to 55 services at peak times causing constant traffic queues while the gates are closed.