Seismic Bracing/Zones of the U.S. 1

[sandiegowriter]

Does anybody know of a website for finding out the seismic zones of the U.S. based on the latitude and longitude? I need this for work. the U.S. Geological Survey does not provide the seismic zones without providing a map & me having to look them up myself. Thank you.

 

[JAE]

Here's what we do:

First go to MapQuest and type in your address of your structure.

http://www.mapquest.com/

This will get you a good "picture" of where your structure is relative to major roads, intersections, etc.

Then, go to:

http://tiger.census.gov/cgi-bin/mapbrowse-tbl

Which is "Tiger Map". Here, you can also place a "pin" on a map and get the Lat/Long. of your address.

With the Lat/Long go to:

http://geohazards.cr.usgs.gov/eq/index.html

and hit the "Hazard by Lat/Lon" under "Seismic Hazard.

This will get you the ground motion values in a table. For UBC and IBC codes, use the PGA of 0.2 sec SA for the short term acceleration and use the PGA of 1.0 sec SA for the long term acceleration, both under the 2%PE in 50yr. column of the table. These two values can then be used directly in the code formulae.

We have inserted hyperlinks into an Excel Spreadsheet that then continues to do all the other seismic calcs per IBC2000.