Looking for the Start of C1, D0, D1, D2 in IRC

[fugeeo]

thread507-428039

I got off track for the Event of the IRC Implementing C1, D0, D1, D2 as seismic regions.
Yet there is not a clear discussion on how it was formulated, whereas the IBC A through F Categories are clearly stated.
Some direct listings for the reference structure starts with the 2014 :
I.
Documentation for the 2014 Update of the
United States National Seismic Hazard Maps
Mark D. Petersen, Morgan P. Moschetti, Peter M. Powers, Charles S. Mueller, ... etc.
II.
Variabilities in probabilistic seismic hazard maps for natural and induced seismicity in the central
and eastern United States
S. Mostafa Mousavi1, Gregory C. Beroza1, and Susan M. Hoover2


I am seeking this to adjunct Caribbean Criteria.

Rfugio

 

[phamENG]

I'm not exactly sure what you're asking for, but I'll give it a shot:

C, D₀, D₁, and D₂ aren't seismic regions, they're design categories - just like the IBC A-F categories. They're also determined in essentially the same way. Where the IBC has a hard cutoff for S₁ that puts you into E for Risk Category 1-3 and F for Risk Category 4, the IRC just adds another subset of S^DS values for E. There's no F because the IRC doesn't cover any risk category 4 structures.

Look at table R301.2.2.1.1 Seismic Design Category Determination in the IRC, and then look at Tables 1613.2.5(1) and 1613.2.5(2) in the IBC. You'll see that the Seismic Design Category is based on S_DS in both cases (although the IBC takes it a step further in case S_D1 controls the design).

 

[fugeeo]

https://www.phrc.psu.edu/assets/docs/Publications/2016RBDCCPapers/Solnosky-2016-RBDCC.pdf

A research article summarized IRC vs. IBC. Caribbean doesn't use Timber for Walls due to V > 140 mph.