Post by lenbrazil on Jul 12, 2007 11:26:15 GMT -4
turbonium said:
lenbrazil said:
Turbo of course ignores the fact the rejected rule change was neither made by NIST nor based directly on NIST recommendations rather it was “developed by the ICC’s Ad Hoc Committee on Terrorism Resistant Buildings” […]
"Damning criticisms"? Yeah right! Once again Turbonium has been shown to be guilty of poor research and completely wrong.
www.iccsafe.org/cs/cc/ctc/WTC/Interim_Report_No_2_101906.pdf
The full ICC was clearly rejecting S05-06/07 not Recommendation 1. The reasons they gave for rejecting it referenced specific aspects of the former that have nothing to do with the latter. As I showed in my previous post other structural engineering bodies were working on proposed code changes based on the recommendation.
The extent to which the WTC disaster will or will not change future high-rise design has yet to be determined. Consensus has yet to be established on the need for some of the more controversial recommendations in the NIST report.
www.nfpa.org/publicColumn.asp?categoryID=&itemID=34343&src=NFPAJournal&cookie%5Ftest=1
www.nfpa.org/publicColumn.asp?categoryID=&itemID=34343&src=NFPAJournal&cookie%5Ftest=1
Your formulation was ‘the engineering community has rejected NIST’s recommendations therefore they reject NIST’s collapse scenario’. Based on what you’ve turned up one does follow from the other and the rejection is not as extensive as you believe.
“Consensus has yet to be established” i.e. not all engineers agree, some do some don’t.
“some of the more controversial recommendations in the NIST report” i.e. some engineers don’t agree with SOME of NIST’s recommendations. The article specifically excluded Recommendation 1 from the "controversial recommendations" category.
An NCE article, just after NIST's report was released....
“At the moment we can’t be sure that the NIST recommendations would produce significantly safer building codes,” said Weidlinger Associates associate principal Dr Najib Abboud.
“We still don’t have enough fire research and testing results. NIST is proposing that all structural elements have the same specified fire resistance, instead of the current practice of columns having double the fire resistance of beams,” he said.
“But we have no proof that this would have any real effect on building performance,” said Abboud.
“At the moment we can’t be sure that the NIST recommendations would produce significantly safer building codes,” said Weidlinger Associates associate principal Dr Najib Abboud.
“We still don’t have enough fire research and testing results. NIST is proposing that all structural elements have the same specified fire resistance, instead of the current practice of columns having double the fire resistance of beams,” he said.
“But we have no proof that this would have any real effect on building performance,” said Abboud.
A single engineer (though perhaps speaking on behalf of his company) questioned one specific recommendation “that all structural elements have the same specified fire resistance”. There is no indication he or his associates reject the need for longer fire resistance or the damage + fire lead to collapse scenario.
Arup risk consulting principal Dr Brian Meacham said it was important not to take building specific and event specific failure information out of context.
“We need to realise that not all factors that contributed to the WTC collapse may be applicable to other building designs,” he said.
“We need to realise that not all factors that contributed to the WTC collapse may be applicable to other building designs,” he said.
I.E. ‘lessons learned from what happened to the WTC towers after they were hit by passenger jets might not be applicable to differently constructed buildings that are unlikely to be hit by large planes’, nothing indicates he rejects NIST’s collapse scenario.
But even the prescriptive “structural frame” option recommended by NIST is not underpinned by meaningful research, said Skidmore Owings & Merrill partner Carl Galioto.
“There are a lot of unproven assumptions about the fire performance of real structures in the prescriptive approach.”
“What exactly does a three hour fire resistance for a column mean, for example? We need more research badly, at federal or even international level.”
www.nceplus.co.uk/b_bank/search_results_details/?report_ID=6936&report_num=0&channelid=6#recommendations
“There are a lot of unproven assumptions about the fire performance of real structures in the prescriptive approach.”
“What exactly does a three hour fire resistance for a column mean, for example? We need more research badly, at federal or even international level.”
www.nceplus.co.uk/b_bank/search_results_details/?report_ID=6936&report_num=0&channelid=6#recommendations
Again the opinion of a single engineer or architect in this case who questions the wisdom of (but doesn’t reject) some specific recommendations. Since he works for a architectural firm that presumably wants to keep the cost of it’s designs low he might not be exactly neutral. There is no indication he rejects NIST’s recommendations as a whole or the collapse scenario.
At best you can say ‘some engineers question some of NIST’s recommendations’. Some of those questions relate to applicability of factors specific to the WTC towers and what happened on 9/11 to differently designed buildings that are unlikely to be subject to the same conditions the Twin Towers were that morning.