THE NEWS that Pier Luigi Nervi's iconic Pirelli building has suffered permanent structural damage from last week's plane impact received a mixed reaction from structural engineers and concrete construction experts.
'Localised damage is acceptable, ' said Gabriele Del Mese who runs consultant Arup's Milan office. 'What the designer has to aim for is prevention of disproportionate collapse. This building responded extremely well.'
But Connell Mott MacDonald managing director John Leuchars expressed concern that the beams had undergone permanent deflection from a relatively small explosion.
'However, the inherent structural redundancy and good continuity of the design meant there was no real risk of failure - and none of progressive collapse, ' he said.
Post-tensioned concrete expert Dr George Somerville agreed with investigators that the most likely cause of the permanent deflection was disturbance to the fixity of the beam ends. 'Some early posttensioned highway structures did suffer from tendon corrosion, which made them more likely to collapse under excessive loading, but corrosion is unlikely in a well maintained building, ' he added.