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Re: Things could be worse ...

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Conrad Harrison wrote:



I thought it was expensive for a house. Re-roofing just automatically suggested house: wrongly.


Putting a new roof on anything after a hurricane seems hazardous. Who and how can the remaining fatigue resistance of the rest of the structure be checked?



Conrad Harrison

B.Tech (mfg & mech), MIIE, gradTIEAust



South Australia


You have to remember that wind, even in an extreme event, is still considered a "service level" load, unlike earthquake.

When we design a structural component for, say, a basic windspeed of 130 MPH (about what you would see at Galveston), that component is designed for the forces computed based on that speed, as if it would resist the load.

Of course, there is a realistic probability that this load will be exceeded, but it is in line with load exceedence probabilities for other static loads per ASCE 7.

So although one might expect structural damage from, in this instance, roof framing, it is just as likely that the framing itself will remain structurally sound. In my experience, we do inspect the structural framing - pretty easy since the cladding is usually gone, all or part :-) And we replace the members that are "bad." But this is rarely found to be the case.

Although there are some similarities when it comes to nuts-and-bolts design, the philosophies of wind and seismic design respectively are actually very different.
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