Seismic Zone Maps?? Where can I find? 2

[nutbutter]

Does anyone know where to find the seismic zone maps (I-V, I believe). I think they were in ASCE 7-02. I don't want to purchase ASCE 7-02 because I only need to look at the map once. Waste of money.

Does anyone know where I can find these online for free? I can find all sorts of more detailed maps on USGS site... spectral acceleration, ground movement (?), etc., but not the simple seismic zone maps. Please help a brotha out.

Peace,
N-Butter

 

[JAE]

Zones don't exist in the codes anymore.

 

[nutbutter]

Shows how much I know!

IBC 2006 appears to still have zones, or "Site Classes".

I'm not a structural guy. Did a little bit of foundation design and drafting when I was working for small consulting firm.

I'm just filling out a builder's risk questionnaire and it asks what seismic zone (numerical) the project is in. Looks like they need to update their questionnaire. I just gave them the IBC Site Class D.

NB

 

[sandman21]

Site class does not equal "zone" old code. You should give the seismic design category.

 

[JAE]

nutbutter,

In current codes in the US, you use the site class (describes the underlying soils - rock or softer?), you use the short and long term accellerations (S1 and Ss), building period, and other factors to determine a seismic design category (A through F) to design for seismic.

The older seismic zones (0 through 4) are somewhat replaced by the seismic design categories.

 

[IFRs]

Go here:

http://earthquake.usgs.gov/research/hazmaps/design/

 

[nutbutter]

Thanks IFRs.

That link definitely is full of information. I guess I just don't know how to get from there to determining a Seismic Design Category.

I know I'm on a "Site Class D" by the information I've gleaned from the geotech report. Through the link I was able to play around and get the Maximum Ground Motion (of 1s spectral response acceleration) maps.

Now I think I'm more confused than ever though. How can I use this information to determine the Seismic Design Category?

Hell, I don't even know if I'm doing the right analysis with that Java applet. I used the "NEHRP Recommended Provisions for Seismic Regulations for New buildings other structures". There's several other analysis methods such as:

-Probabilistic hazard curves
-Probabilistic Uniform Hazard Response Spectra
-ASCE 7 Standard, Min design loads
-IBC
-IRC
-NFPA 5000 Building Construction and Safety Code


Man, I'm totally lost now. Is there a certain analysis that I need to perform to determine this "Seismic Design Category", or can I get there from any of these analysis methods?

If anyone could give a brief summary of how to use this tool to determine the Seismic Design Category, I would be extremely grateful.

-NB

 

[slickdeals]

You will need to compute your Sds and Sd1 based on the Ss and S1 and Fa and Fv (soil type) parameters. Once you have these values, you can go into one of the tables (don't recollect which one) and then classify it based on both Sds and Sd1. The more stringent one controls.

 

[msucog]

http://www.bssconline.org/FEMA451B/451Bchapters.htm

http://www.bssconline.org/pubs/downloads.html

http://www.iccsafe.org/e/prodshow.html?prodid=9294S06&stateInfo=ddtWcabiJikEjccc5952|5

(CodeMaster - Seismic Design Category (2006 IBC/ ASCE 7-05))-$5


you could probably ask the geotech for assistance...we typically provide seismic design parameters on our projects. the links above will put you on the info (plus a whole lot more) you need. i suggest purchasing a copy of ASCE7-05...well worth the money.

you should probably (guessing here) be using the IBC 2006 maps with ~2475 yr return period (2%/50). again i'd suggest you receive input from the geotech...an experienced engineer should be able to get you to the SDC with all the parameters relatively "easily".

i won't go wading off in to site classification and the different approaches to get this parameters. however, taking a more sophisticated approach could save the client a substantial amount of money.

good luck.