huge differences in allowable bearing capacities?
huge differences in allowable bearing capacities?
(OP)
I am at a loss to why I am finding such huge differences between allowable soil bearing capacities in the IBC vs NYC building code.
See the International Building Code table 1804.2 in the below PDF:
http://www-scf.usc.edu/~mosheikh/ibc_chap18.pdf
Table 1804.2 clearly shows gravels as 3000 PSF.
vs.
NYC building code (based off of the UBC):
http://www.nyc.gov/html/dob/downloads/bldgs_code/b...
Here Table 11-2 Note#4 shows gravels ranging from 12000 to 20000 PSF.
The NYC building code is about the same order of magnitude higher than IBC across the board for all soil/rock types. Footing sizes using IBC could be up to 7x as large!
Anyone know why, and which one should a shallow foundation be designed with?
See the International Building Code table 1804.2 in the below PDF:
http://www-scf.usc.edu/~mosheikh/ibc_chap18.pdf
Table 1804.2 clearly shows gravels as 3000 PSF.
vs.
NYC building code (based off of the UBC):
http://www.nyc.gov/html/dob/downloads/bldgs_code/b...
Here Table 11-2 Note#4 shows gravels ranging from 12000 to 20000 PSF.
The NYC building code is about the same order of magnitude higher than IBC across the board for all soil/rock types. Footing sizes using IBC could be up to 7x as large!
Anyone know why, and which one should a shallow foundation be designed with?





RE: huge differences in allowable bearing capacities?
I can't seem to find how to edit my post.
RE: huge differences in allowable bearing capacities?
Sorry, but personally, I have no clue here why the difference of that magnitude...
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: huge differences in allowable bearing capacities?
RE: huge differences in allowable bearing capacities?
NYC is the governing code for the project so obviously that is what I would use, I was just nervous about such large discrepancies.
RE: huge differences in allowable bearing capacities?
RE: huge differences in allowable bearing capacities?
obviously in the end, testing is the going to give the most realistic bearing capacity numbers.
RE: huge differences in allowable bearing capacities?
Untied States land area equals 3,803,290.00 square miles.
Or it could just be that the New York code officials feel more comfortble with their numbers due to the land area (and the testing in this area of the soils done) it is being applied over than the IBC people.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: huge differences in allowable bearing capacities?
RE: huge differences in allowable bearing capacities?
Try using Terzaghi or other bearing theory, assuming phi'=35, gamma=125 pcf, 3 ft wide strip footing, embedded 3 ft below grade. Does 3000 make sense w.r.t. bearing theory?
RE: huge differences in allowable bearing capacities?
RE: huge differences in allowable bearing capacities?
RE: huge differences in allowable bearing capacities?