The new bridge links the first and second floors of Alfred Waterhouse's 1885 museum with its 1912 extension. The original connection was a small first-floor corridor above the arch, which is the main entrance to the museum. The bridge runs alongside the corridor, now a seating area.
The bridge is a simple steel structure in a glazed enclosure, which reveals the original building behind, allows visitors to orientate themselves and contrasts with the relatively low levels of lighting (75 lux) in some galleries.
First- and second-floor decks are formed of 8mm steel plate with 150 x 10mm rib stiffeners.To avoid the use of foundations, which would disturb services buried in the street below, the decks are supported from the original buildings; to reduce deflection they are braced with a series of robust 22mm-diameter rods suspended from the roof structure.The perimeter steel plates of each deck mask the timber floor build-up and, on the second floor, the slope.
The frameless 10mm toughened glass wall panels are bolt-fixed to glass fins, which in turn are clamped to the floor plates.
This creates a zone for trench heaters and air circulation around the decks; the fins also support stainless steel handrails.
Green-tinted glass was selected to achieve a high shading coefficient while matching the original museum graphics.
The division of glass panels match the spacing of the ribs, which in turn reflects the asymmetry and internal symmetries of the original bridge.
The bridge was the only suitable place for a large air inlet to draw air into the building.A series of louvre panels with dampers and filters are set above the original bridge copings.