Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

On thin ice


I read with interest but no pleasure the detailed report on the collapse of the new Paris Airport building.

With the benefit of hindsight it appears that the constant thickness of the concrete shell - at less than one-hundredth of its span and with some 50% of the width sacrificed for windows - was rather thin.

This would have reduced dead weight and stiffness and hence reaction forces at the supports, but would tend to accentuate stress levels and increase movements associated with resisting loads, some of which - for example wind and temperature - would be reversible.

In the vicinity of the escalator cut-outs the concrete compressive stresses may have been high. This may have resulted in accelerated creep progressively eating away from the ultimate strain capacity of concrete. When combined with reversible effects, this could potentially cause failure.

Although this is only a conjecture, I believe concrete stresses for the serviceability conditions should be controlled to within a reasonable limit, especially for unusual structures.

Furthermore, greater emphasis should be placed on proper understanding of structural behaviour, including second order effects, and not merely on automated analysis of structures which can sometimes be misleading.

Arvind Kumar, (F), 2 Penn Road, Beaconsfield, Buckinghamshire, HP9 2PX

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.