USGS Seismic Design Maps and the Government Shutdown.
USGS Seismic Design Maps and the Government Shutdown.
(OP)
Due to the government shutdown, the website geohazards.usgs.gov is unavailable. I use this website to get all of my seismic design parameters when determining my loads.
What are other avenues to get these design parameters until the government gets up and running again?
David
What are other avenues to get these design parameters until the government gets up and running again?
David






RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
David
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
Mike McCann
MMC Engineering
RE: USGS Seismic Design Maps and the Government Shutdown.
So to get the best value for my client, I would like to have the most accurate values possible. While yes I could take an educated guess at the closest design parameters, I would prefer to have something with a much better accuracy than what I would get using those maps.
David
RE: USGS Seismic Design Maps and the Government Shutdown.
http://earthquake.usgs.gov/hazards/products/conter...
RE: USGS Seismic Design Maps and the Government Shutdown.
The ‘essence of your problem’ is that we/they don’t know those values to +/- one square foot in position on the face of the earth. Does that web site guarantee those values, and that your building will never have any problems when you use them. Are those lines on the maps perfectly vertical and running to the center of the earth? Or, do some of those EQ zones change on an inclined, even ragged, plane. In which case the footings in a wall might be in one zone, while the first floor is in another.
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
I doubt those values are accurate to +/- 5 miles. So both ends of the building will experience the same earthquake. Sure, the digital maps are precise, but the accuracy is based on the lousy geologic data. that includes estimated locations of faults, estimated depths and locations of bedrock and a limited number of seismographs and other instrumentation. The only way to tighten that up is with your own geologist on-board telling you different.
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
That's just stupid.
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
In the meantime, for bid designs, the maps are of sufficient resolution in most areas as to yield a negligible variance between designs. In areas similar to those dgraff mentions (LA County), all contractors and engineers share the same handicap and should proceed with a level of conservatism with which they agree.
For final designs, I have found the project geotechnical report to be invaluable in determining the appropriate seismic parameters.
RE: USGS Seismic Design Maps and the Government Shutdown.
You can get S1 value ftom ASCE 7-05 Figures 22-2 to 22-14
Fa is from IBC 2009 Table 1613.5.3(1), page 341
Fv is from IBC 2009 Table 1613.5.3(2), page 341
SMs is Fa*Ss
SM1 is Fv*S1
SDs is 2/3*SMs
SD1 is 2/3*SM1
RE: USGS Seismic Design Maps and the Government Shutdown.
I understand your dilemma. I am attaching a screen shot of L.A. County from the ASCE 7-10 design maps. In some place, it looks like the width of a line is greater than the clear distance between the lines. The USGS tools make life much easier.
I only have a couple suggestions. Have you tried downloading the JAVA script tool that is good up to ASCE 7-05? The design values should be fairly close to ASCE 7-10 (I know one location in L.A. where Ss is going up 10% - the new code takes effect on 1/1/14 in California). Also, you might look at the USGS data sets to see if it can be used (http://earthquake.usgs.gov/hazards/designmaps/data...).
RE: USGS Seismic Design Maps and the Government Shutdown.
http://geohazards.usgs.gov/designmaps/us/applicati...
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
RE: USGS Seismic Design Maps and the Government Shutdown.
SS and S1 values from USGS website during U.S. government shutdown
http://skghoshassociates.com/resources/miscellaneo...#!