Allowable soil bearing pressure
Allowable soil bearing pressure
(OP)
Under UBC the maximum allowable soil bearing pressure was 1000 psf (without the need for soils report). Under CBC 2013, TABLE 1806A.2, the same soil bearing pressure is 1500 psf. The same Dead load + Live load governs the design, using the working stress design. Any body know what was the reason for the increase in the allowable soil pressure?






RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
Now, it seems a lot of geotechnical reports allow just 2,000 psf, even when they have soil borings. And as you said, codes are also more conservative.
Have there been problems over the years with settlement?
DaveAtkins
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
It could also be that the owners, architects, or other engineers that are selecting the geotechnical engineers on the basis of cost. So the number of borings goes down, the amount of laboratory testing goes down, the amount of time spent doing any type of analysis goes down and they send basically the same report that they have sent for the last 50 jobs, because no one is willing to pay them to actually do any engineering.
I've been in this business for over 25 years, and the cost of a geotechnical report for typical commercial projects is within 20 percent of what it was when I started.
Mike Lambert
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
-- In my opinion, the Geotech services are terribly commoditized (I believe the Architects & Structurals have about the same degree of impact as the cheap developers & the atrocious Public entities).
-- Geotechs do not appear to be doing any significant field or lab work compared to 30 years + ago (In my area of Western Colorado, I am amazed at the vast range of native & fill conditions which ALL result in an allowable of 1300 to 1600 psf).
-- As development has occurred, most towns/cities have been moving into areas of poorer subsurface conditions, probably justifying the pessimism of the Codes.
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure
RE: Allowable soil bearing pressure