The design principle is a symmetrical structure of twinned cantilevered cradles suggesting a formal maritime gateway to the city. The double swing opening sequence of the bridge is an appropriate event to compliment the arrival of sea craft into the heart of Dublin. The structural form of the two main bridge elements is based on a simple balanced cantilevered principle which provides an intrinsically efficient structure for the scale of opening required, resulting in reduced structural mass to create a permeable and dramatic silhouette.
The two central opening sections rotate in plan about a central pier to allow a free 33 metre open width. The operating system for the rotational movement is essentially two hydraulic rams driving a slewing ring arrangement located in the void of the cradle base. The balanced cantilever achieves its support via a cradle, comprised of four tapered steel sections, profiled to allow the flow of maximum load transfer.