un peu de respect pour une discussion polie et constructive svpMon père a suivi ...

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un peu de respect pour une discussion polie et constructive svp

Mon père a suivi de près la construction du WTC, et en 1983 à New-York nous avons visité le chantier d’un gratte-ciel en début de construction, donc j’ai une idée assez claire du gros oeuvre, oui.

En (re) cherchant un tout petit peu des sources sur mes affirmations qui étaient des souvenirs, je trouve le livre Failure Consequences and Reliability Acceptance Criteria for Exceptional Building Structures avec ce passage :

For scenarios Safety 10 and Safety 30. the cheapest solution is ensured by the Cushioning Structure with 10 and 71 million USD, this again because the cushioning columns are inserted only in the 12 respectively 32 upper stories of the building. For scenario Safety 50, the Steel Structure yields the minimum costs because, compared to the other structures, the loss of floor space is significantly lower.

In comparison, the cost of the two WTC towers (construction period 1966-1977) was 900 million USD (169]. Today they would cost 4.7 billion USD, or 2.35 billion USD per tower, see Annex B.

Major benefits of the concrete walls and partially of the composite elements arc a higher fire resistance and a higher resistance against initial damage due to accidental action (sec Table 4.4). Table 4.8 shows the minimum undamaged portion of a structure, designed to withstand the failure of a story, required to prevent the failure of a story. It is seen that all structures arc very redundant and that the failure of a story is quite unlikely. Therefore, all structures, but the Cushioning one. are redesigned so that they arc able to prevent story failure in the case the damage assumed in Table 4.4 and 4.5 occurs.