R401.4 Soil Tests
In lieu of a complete geotechnical evaluation, the load-bearing values in Table R401.4.1 shall be assumed.
PRESUMPTIVE LOAD-BEARING VALUES OF FOUNDATION MATERIALSa
|CLASS OF MATERIAL||LOAD-BEARING |
(pounds per square foot)
|Sedimentary and foliated rock||4,000|
|Sandy gravel and/or gravel (GW and GP)||3,000|
|Sand, silty sand, clayey sand, silty gravel |
and clayey gravel (SW, SP, SM, SC, GMand GC)
|Clay, sandy, silty clay, clayey silt, silt and |
sandy siltclay (CL, ML, MH and CH)
For SI: 1 pound per square foot = 0.0479 kPa.
- Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
- Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing capacity shall be determined by a soils investigation.
Instead of a complete geotechnical evaluation, where top or subsoils are compressible or shifting, they shall be removed to a depth and width sufficient to ensure stable moisture content in each active zone and shall not be used as fill or stabilized within each active zone by chemical, dewatering or presaturation.