# FBC code interpretation



## MetroRAFB (Aug 29, 2007)

I'll start with my question, and follow up with a little more info:

In your opinion, does the current 2004 FBC allow live load reductions in the High Velocity Wind Zone?

In the load combination section of Chapter 16 of the FBC for non-HVWZ areas it says that it's permitted to reduce the effect of any two or more live loads by 25% and add the dead load. I'm trying to figure out if that's allowed in the HVWZ.

Here's my take: In the HVWZ section at the end of Chapter 16 of the FBC-Building, their wording gets pretty convoluted as to whether it's permitted or not. It basically says that you can do whatever ASCE-7 says you can, and therein lies my hangup. In chapter 2 of ASCE7-02, one of the permitted load combinations appears to have the same 25% reduction in the live loads, but I'm not sure I'm interpreting it correctly.

I'm designing a wood LVL beam supporting roof trusses, and the software program I'm using takes this 25% live load reduction in the design of the LVL. I'm not sure whether or not this design is permitted in the HVWZ. I've got calls into the software tech people, but I imagine I'm in for several hours on hold with the national company before I'm able to find their resident expert in the FBC, if I can even find him or her.

Any thoughts and opinions are appreciated.


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## grover (Aug 30, 2007)

I'm not a floridian structural engineer, but... isn't it safe to assume that under worst-case HVWZ conditions in Florida, all personnel (and their subsequent live load) would have been evacuated from the building?


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## MetroRAFB (Aug 30, 2007)

You would think, but that level of common sense doesn't make it into the pages of any building codes I've ever seen.


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## Guest (Aug 30, 2007)

^^^ I will echo that statement.

There are MANY times when people are told to leave ... imminent danger ... get out ... evacuate. Do you know there are some people who will just not leave?

So ... as far as grover's assumption. Survey says: GOOSE EGG hmy:

:laugh:

JR


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## grover (Aug 30, 2007)

OK, let me rephrase the question then, to accomodate the lowest common denominator:

I'm not a floridian structural engineer, but... isn't it safe to assume that under worst-case HVWZ conditions in Florida, all personnel (and their belongings) would have been evacuated from the building at appx 150mph?


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## MetroRAFB (Aug 30, 2007)

grover said:


> OK, let me rephrase the question then, to accomodate the lowest common denominator:
> I'm not a floridian structural engineer, but... isn't it safe to assume that under worst-case HVWZ conditions in Florida, all personnel (and their belongings) would have been evacuated from the building at appx 150mph?



Nope, some structures in the HVHZ have to withstand 150mph conditions without failure.


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## Guest (Aug 31, 2007)

^^^ Yeppers. Correct.

JR


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## GCracker (Sep 19, 2007)

I know I'm coming in a little late with this, but I believe the minimum roof live load in the HVWZ is 30 psf and non-reducible. I haven't designed a structure in south FL in the last 3 years, so it may have changed.


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