Seismic & Wind load

Started by Keliy23, June 01, 2006, 06:04:53 AM

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I have some questions about Seismic & Wind Loads.
What makes the difference in the mph in the wind loads. Would that be hurricane straps, etc...
Do these tie downs, etc... make the difference in Seismic too.
The plans I ordered came with Seismic C and Wind Loads of 80mph.
I live in coastal South Carolina and it appears that I need Seismic D1 or D2 and Wind Loads of 100, 110, 120 or 130.
How do I determine which of these my house will be, or do I mark this on my plans and the builder meets these requirements with hurricane straps, etc...

Thanks for the help.


I'd thought that South Carolina had very low seismic possibilities.

Not all that true (but I found neither the 1-2-3-4 scale I'm familiar with nor your alphabetic one with a very quick search).

No idea about how you go about changing plans.  Talk to the architect?  Ask your builder?  Get a couple of hours with an engineer?  

Some of what you design for is what you are afraid of.  There was a horrible story around yesterday about how the levees in Louisiana were designed--apparently the designers threw out the data on hurricane Camille because it was out of line on the high side.


I think the engineer is what you will end up with.  There are various price ranges and qualities of engineers - some half as high as others and as good or better.  Ask around for referrals - building department may give you clues but will not generally recommend one over the other- watch for hints from them as to one being better though.

He can modify your plan to meet the requirements -- then he stamps it -- takes your money and it is ready for the building department approval process.

Usually they will request corrections - you go back to the engineer - maybe give him more money - back to the building dept. then hopefully they accept it and take more of your money and fees then give you your permit.


Thanks for the help.
I found the information on line.

Thanks Kelly

I would post the map but it is a pdf and I do not know how to downsize it to 250kb.


Don't post the map, just the URL, preferably with an idea of how big that .pdf file is.


I didn't even think of that...
Well this information can be useful to anyone building...

This link goes to the US Seismic Load Map...

This link goes to a document for wind loads along coastal SC, NC, & VA
Page 6 is what show the map but it might be stated just for SC

I used my bosses book: Data Book For Civil Engineers "Design" by Elwyn E Seelye
for the snow loads, if my scanner worked I would scan that map

Thanks Kelly...