Very Simple Seismic Question

[theonlynamenottaken]

Calculating Seismic Base Shear using the Simplified analysis procedure in IBC chapter 16:

I'm absolutely sure I'm right on this, but I have no one in this office to verify me. When I pull Ss and S1 (mapped spectral accelerations) off of the contour lines on these maps of the U.S. they are given in %g. For example, for Oregon coastline its 125% - 150%. When I plug these values into equation 16-38, 16-39 -> Sms = FaSs I'll plug in 1.25 or 1.5, correct?

Thanks

 

[mrMikee]

You are right. The hazard maps use percent (probably for clarity on the map) but the equations use the actual number. If you are by yourself in an office you might want to get the book by Alan Williams titled "Seismic and Wind Forces, Structural Design Examples" from the ICC. It does help to see worked examples and this is one of the better single books in my opinion.

Regards,
-Mike

 

[theonlynamenottaken]

mrMikee,

Thanks! I've been looking for a book with seismic force calculation examples... I'm on Amazon looking for a used one now.

 

[PSlem]

The one from Structural Engineering Association of California is good. Sold through ICC.

 

[whyun]

http://www.iccsafe.org/e/prodcat.ht...ENG,EN-Struc&stateInfo=AdLrbbaxdOfxkjdP6946|4

Look into the 2000 IBC Structural/Seismic Design Manual - Volume 1. It should have many examples including seismic coefficient example. I do not have this book but I have all three volumes based on 1997 UBC. Therefore, I assumed similar. I'm not sure if they published one for 2003 IBC. You may contact ICC about that. Good luck.

 

[mrMikee]

I have the IBC 2000 version of the "Structural/Seismic Design Manuals" a three volume set (also available separately) that I agree is a good reference. And volume I goes thru the spec section by section which I think is a good approach. As a first book purchase I might still pick the Alan Williams text which does wind also, but they are both good enough that it doesn't make a difference. In fact all the books from ICC that I have bought are very good, except for the IBC spec itself, but that's another story.

-Mike

 

[akastud]

I purchased Civil & Structural Engineering: Seismic Design of Buildings & Bridges, 5th Ed. from Kaplan. It has some typos because it is fairly new in regard to the IBC, but it is very good at explaining how to apply the seismic provisions of ASCE 7 and the 2003 IBC. It is actually a Exam prep book, but I would reccomend it to anyone trying to convert to the new seismic provisions. It is fairly cheap too, about $50.

akastud