Turning to page 20, I read that it sits on hollow steel piles, has a pair of complex steel arches supporting a concrete deck of thin concrete planks by means of cables. All of which makes me ask how you define sustainability!
Hollow steel piles will eventually be subject to corrosion, as will the arches, despite regular painting.
Hangers, like their larger counterparts the cables of suspension bridges, will not have an indefinite life and will need regular maintenance. The cover to the reinforcement of thin concrete planks cannot, by definition, give it protection for long.
Elegant the footbridge undoubtedly is, sustainable long-term it cannot be.
Only structures that are in compression and do not suffer corrosion are sustainable in the long run.
Look at any mediaeval arch bridge or cathedral.
John M Gill (F), Raisbeck Lodge, 10 Darras Road, Ponteland, Newcastle upon Tyne, NE20 9NX