Two giant glass floors 42m (138ft) above the Thames have opened at Tower Bridge as part of a new attraction marking its 120th birthday.

The scheme by Purcell Architects took a year to implement and now offers visitors a completely new view of the bridge, the river and the lifting process from high-level walkways across the Thames.

“Purcell is delighted to have contributed to such a unique project, which is visionary in all senses of the word. The ‘unseen before’ view adds another dimension to people’s understanding of the iconic Bridge and the wider context of London,” said Purcell’s Martin Dunseath. The practice has also worked on the Coworth Park ‘eco luxury’ spa in Surrey and the National Maritime Museum, London, among many other high profile UK and international projects.

Bridge House Estates and the City of London Corporation, who headed up the scheme, were required to submit two separate planning applications as the bridge spans the boundaries of both Tower Hamlets and Southwark boroughs.

There are two glass floors, one on the west walkway, which is now open, and one on the east, which opens at the beginning of December. Each comprises six 530kg panels, supported by a 1,000kg carbon steel framework. The panels sit in spaces created in the steel lattice structure of the Grade I listed Bridge. The reinforced glass will allow visitors a ‘bird’s eye view’ down onto the road and river beneath, but the bigger draw will be at lifting times, when they will get the chance to see the bridge raise up beneath their feet to allow ships up and down river.

Tower Bridge has operated as a historical visitor attraction since 1982. This new project has enabled it to refresh its Great Bridges of the World exhibition and launch a free smartphone app to complement the walkway views. ‘Raise the Bridge’ takes visitors through an augmented reality window in the glass, showing a 360 degree panoramic view of the Bridge as it opens.

The £1m (US$1.6m, €1.3m) walkways project has been funded by the City of London Corporation and revenue from the Tower Bridge Exhibition, which currently attracts 600,000 visitors a year.

UPDATE:

The walkway hit headlines early this week after it emerged a beer bottle smashed one of the panes of glass during a weekend function.

Part of the top layer of the transparent walkway was shattered when an empty beer bottle fell from a tray being carried by a member of the catering team during an event.

Chris Earlie, head of Tower Bridge, said: “Tower Bridge Exhibition’s engineering team attended the site on Saturday morning and the sacrificial glass panel was replaced on Sunday morning. The exhibition space remained open to the public as normal and no visitors were at risk.”

“The new glass floor has four layers of glass with the sacrificial layer on top of that – this is installed so that it can be replaced if it is scratched or damaged.”