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 PRESSURE (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, GM and GC)||2,000|
|Clay, sandy silty clay, clayey silt, silt and sandy siltclay (CL, ML, MH and CH)||1,500b|
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.
R401.4.1.1 General and Where Required for Applications Listed in Section 184.108.40.206.1 Regulated by the Department of Housing and Community Development
Foundations and soils investigations shall be conducted in conformance with Health and Safety Code Sections 17953 through 17957 as summarized below.
Each city, county, or city and county shall enact an ordinance which requires a preliminary soil report, prepared by a civil engineer who is registered by the state. The report shall be based upon adequate test borings or excavations, of every subdivision, where a tentative and final map is required pursuant to Section 66426 of the Government Code.
The preliminary soil report may be waived if the building department of the city, county or city and county, or other enforcement agency charged with the administration and enforcement of the provisions of Section R401.4.1.1, shall determine that, due to the knowledge such department has as to the soil qualities of the soil of the subdivision or lot, no preliminary analysis is necessary.
If the preliminary soil report indicates the presence of critically expansive soils or other soil problems which, if not corrected, would lead to structural defects, such ordinance shall require a soil investigation of each lot in the subdivision.
The soil investigation shall be prepared by a civil engineer who is registered in this state. It shall recommend corrective action which is likely to prevent structural damage to each dwelling proposed to be constructed on the expansive soil.
The building department of each city, county or city and county, or other enforcement agency charged with the administration and enforcement of the provisions of this code, shall approve the soil investigation if it determines that the recommended action is likely to prevent structural damage to each dwelling to be constructed. As a condition to the building permit, the ordinance shall require that the approved recommended action be incorporated in the construction of each dwelling. Appeal from such determination shall be to the local appeals board.
A city, county, or city and county or other enforcement agency charged with the administration and enforcement of the provisions of Section R401.4.1.1, is not liable for any injury which arises out of any act or omission of the city, county or city and county, or other enforcement agency, or a public employee or any other person under Section R401.4.1.1.1, R401.4.1.1.2 or R401.4.1.1.3.