Tuesday, September 21, 2010

Plastic hingeing and other things

But in a letter to Mr Shadbolt, structural engineering expert John Scarry, of Auckland, said a modern design should not need structural strengthening at all.

In 2002, Mr Scarry wrote an "open letter" in which he exposed "the parlous state of the structural engineering profession and the construction industry in New Zealand".

He told Mr Shadbolt several major stadia had been on the verge of collapse during or immediately after construction, under no snow loading at all.

"These include the Waitakere Trusts Stadium, which was overstressed 900 per cent at its main support points, and the Vector Arena which had, I believe, three major defects, two of which almost caused total collapse."

Mr Scarry claims one of the major defects related to eccentric steel cleat connections which, until recently and almost universally, had been under-designed in New Zealand, causing several to fail as a result.

To a layman like me, with an engineering bent, seems like an awful lot of the "Don'ts" associated with eccentric steel cleat connections may have been ticked when under normal load. A light snow loading was the straw that broke the camel's back. And the council knew about it at least eight years ago.

Now we are watching the council and associated engineers becoming unhinged, like the building did a few days ago.

ps Hasn't Mayor Bob hidden the Waitakere Stadium's failure/overstressing well? I would wager the ratepayers never knew that. Or that it would show on a LIM report!

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