Rowecord Engineering Ltd, UK

Steel suspension bridge

The Peace Bridge is a 312m long, 4m wide curved suspension bridge creating an important new link for pedestrians and cyclists across the River Foyle from the city to the waterside in Derry, Northern Ireland.

Model used for calculating weights and centres of gravity

The main deck comprises of a 5 sided fabricated box section and cantilever arms. These were fabricated in 32m long sections weighing approximately 65 tonnes each in Rowecord's works in South Wales and were then transported by road and ferry to site. On arrival, the decks were fitted out with lighting and cables prior to being lifted by a barge crane on to the temporary supports. Once positioned on the temporary supports, the deck units were bolted to the adjacent sections and then the joints fully welded. When the deck had been completed and the pylons erected, the deck was hung from the cables and lifted off the temporary works.

The bridge was modelled using Tekla BIM software with the main challenge on the project coming from the complex geometry of the deck. As well as being used to create the general arrangement and fabrication drawings, the model was extremely useful in developing the temporary works and for calculating weights and centres of gravity for the transportation and lifting plans. The model was also used for surveying the bridge during erection and the trial erection. A 3D DXF of the model was used by the surveyors to check and record relevant points along the structure. The accuracy of the model and the control over the geometry during fabrication and erection was a major contributor to the success of this project.