Basilica of Aquileia - Glass walkways over early-Christian mosaics | Ottavio Di Blasi

The floor of Aquileia’s Basilica dates back to the 4th century. It’s one of the largest and best preserved mosaics in the whole of Christianity, which UNESCO recently declared part of the human heritage. To assure that future generations can enjoy this unique handmade, it was absolutely necessary to allow the floor being visited without being walked over by the 500.000 visitors who every year reach the Basilica. The first design guideline was minimal obtrusiveness: the project must cause as little visual impact as possible. The second one was reversibility: it must be possible to dismantle the project at any time. The project is divided into two parts. The first one, in the medieval Basilica, consists in glass pathways resting on the column plinths and a footbridge crossing the Basilica’s central aisle, spanning 12,85 metres. This is a bearing structure for walking across that has never actually been built. The second one, in the North Hall dating back to 4th century A.D., involves constructing glass walkways suspended from the ceiling. The pathways and handrails are all made of laminated glass; the problem of wear-and-tear to the walking surface has been dealt with by means of a removable, cheap and easy to replace layer of thin reinforced glass protecting the structural one. The most intricate building feature is the walkway running across the Basilica’s main aisle. The footbridge’s structural design features a 4 lenticular laminated and reinforced wind-braced glass beams on the horizontal floor level: the various sheets of glass forming the bearing beams are held together by the force of the pre-compressed cables placed along the two top and bottom edges of the beams.