1) The firm's strong belief that if the structure could be made to work, they would find out how.
2) The engineers' high level of skill in pure engineering.
Arup engineers have worked on most of the landmark structures of the late 20th century, from the Sydney Opera House to the Lloyds' building in London. The firm is well-known for its innovative approach to problem solving and the expertise of its engineers and materials specialists.
With its exposed, hillside position, the influence of the wind on the structural design of the Angel cannot be too highly stated. The statue stands 20 metres tall with a wingspan of 54 metres and is likely to be exposed to winds of 100 mph or more.
Where a human figure leans to adjust to the loading imposed by gusts of wind, the statue must withstand these forces in a static state. So the connection of the wings to the body, the strength of the ankles, and the connection to the ground are all vital points in the design.