Geo Report Seismic Design Catagory C

[DJYork]

According to 1802.2.6 & 7 of the IBC, it is required to have a Geotech Report for seismic categories C and above. Is there something that is acceptable for a Geotech report not be performed if a more stringent analysis is used? I was informed there was such an entry, but I am unable to find it.

FYI, this is more of an office discussion instead of me trying to design without a Geotech Report.

 

[jdonville]

DJYork,

If I recall correctly (IBC is at the office, not at my home), IBC class C is something like "stiff soil profile". Basically, this means that unless you are building on rock, you need a geotechnical report.

Seeing as getting the geotechnical capacity and response to structural loads wrong by making an incorrect assumption can influence the construction cost of a new design up to 40 percent (seen that number bandied about by Poulos, I think), unless the structure was cheap to replace or construct, why wouldn't you do a geotechnical investigation?

I suspect that the answer to your question remains academic rather than practical...

Jeff