British Airways i360 at Brighton

Structural Designer

Jacobs

Client Name

Brighton i360 Limited

Location

Brighton, UK

PRINCIPAL CONTRACTOR: Hollandia Infra b.v.

MAIN CONTRACTOR: Nardo Hoogendijk    

ARCHITECT: Marks Barfield Architects       

KEY TEAM MEMBER: Pomagalski SAS ("Poma")  

KEY TEAM MEMBER: J T Mackley & Co Ltd Foundations substructure and beach building

PROJECT DESCRIPTION

British Airways i360 is the world's tallest moving observation tower. It carries 200 passengers at a time in a circular glass viewing pod, which rises slowly from beach level to a height of 138m. The tower is 162m high and only 3.9m in diameter (holding the Guinness Record for the "world's most slender tower"). The tower was delivered by barge directly to the beach and erected by a novel "top down" method without the use of cranes. It features purpose-designed perforated cladding to minimise vortex shedding, and sloshing liquid dampers to limit wind-induced dynamic movements.

Judge's comment:

The hardest job for the structural engineer was to ensure that the i360 wouldn’t wobble in the wind. The engineers combined two special features so they could be absolutely sure it was solid as Brighton rock.

The outer skin is actually perforated and this allows the air to pass through it – this is something they also do to tall chimneys for the same reason. In addition, any vibration is damped out by having a series of “sloshing liquid dampers” inside the tower. When the tower tries to vibrate the liquid (water) starts to move too and the “sloshing” counteracts the tower’s movement – the tower rocking and the water sloshing cancel each other out. This is a first in the UK.