cfd: Hurricane Irma

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Re: cfd: Hurricane Irma

Postby thschrader » Thu Sep 14, 2017 10:45 am

GeneFC wrote:
Wed Sep 13, 2017 8:20 pm
In South Florida all houses must now be designed and constructed to withstand 250 km/h winds.
Hello Gene,
thats very interesting. We are building antenna-systems for cellphone-communication.
In germany, we design the towers/buildings to withstand a wind loading at 150 km/h.
That gives a pressure of 1,10 kN/m^2 (110 kg/m^2). When using 250 km/h, you get
a pressure of 3,00 kN/m^2. Your houses must have a "load-capacity" by a factor
of 3 than in germany ;) . Do you use the same design manual for the whole US?
regards Thomas

EDIT 14.09.2017:
Especially I am intersted in how you design your communication system at 250 km/h,
when the antenna itself has a survival-speed of 200 km/h?
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Re: cfd: Hurricane Irma

Postby bill » Thu Sep 14, 2017 12:36 pm

Lots of homes still standing

Hurricanes are like Earthquakes, how and where resonant energy focuses (less scrapnel - flying debris damage in the case of hcs) yields the most impact/damage.

Additionally, Hurricanes are not isotropic generators in a confined plane; your results may vary; and they do dramatically!
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Re: cfd: Hurricane Irma

Postby GeneFC » Fri Sep 15, 2017 1:53 am

thschrader wrote:
Thu Sep 14, 2017 10:45 am
Do you use the same design manual for the whole US?
First, I am not a building designer, only an interested amateur. I cannot answer your specific technical questions.

The extreme design requirements are only in a few locations, such as south Florida. It is very common for the basic house construction to be concrete blocks with solid concrete beam reinforcement and lots of steel. Continuous steel rods (16 mm dia) run from the foundation to the roof. Every roof truss is anchored to the walls with steel straps. There are numerous other requirements, and the construction inspections are very rigorous. Important components must be pre-tested and included on an approved list.

Commercial buildings and structures such as antennas have similar types of requirements.

Edit: These requirements are only about 15 to 20 years old, and they are still evolving. It is now quite common to see little damage to new construction, and complete destruction to older construction in the same area.