seismic site class investigations

huangyhg

seismic site class investigations
i was recently asked by one of our (non structural) engineers whether or not to require the geotechnical engineer for a project of ours perform the necessary tests to determine seismic site class. i advised against it.  my reasoning was that there's an extra cost involved and it seems the geotechnical investigation always results in class d.  since we can normally assume class d without any tests, why pay the money?
do any of you see it that way?
i've asked a few of our local geotechs to weigh in on this and most of them reply that they have a pretty good understanding of the region we are in and, with a fairly low seismic activity, it wouldn't really be necessary.
they all said they knew that we were in d based on previous borings taken historically.

see thread 256-115114