Peer-to-Peer Standards Exchange

 Seismic Load discrepancy between 7-10 and 7-16

  • ASCE Standards
  • Earthquake and Earthquake Loads
Cody Partlow's profile image
Cody Partlow posted 04-12-2024 03:49 PM

I have a project in Vonore, TN where we are adding on to something that we designed when the Reference code was ASCE7-10.  The reference code now is -16 and it appears the seismic values have jumped significantly.

7-10 values Ss = 40

7-16 values Ss = 70

Any idea as to why these values bumped up 75%?

Ronald Hamburger's profile image
Ronald Hamburger

Cody, the seismic values in ASCE 7-10 are based on the 2008 National Seismic Hazard model developed by USGS.  The values in the 2016 edition use the 2014 National Seismic Hazard model.  In comparing disaggregated values of seismic parameters obtained form the two models, it appears that in both cases, the shaking values were dominated by a nearby (~ 5km) fault.  In the 200 model, the dominant magnitude for this fault was about 5.5.  In the 2014 model this values seems to be somewhat higher at about 6.5.  So, the short answer to your question is that in the intervening years, seismologists at the USGS formed a different opinoin as to the potential magnitude of earthquakes on a nearby fault.