The load-bearing values used in design for supporting soils near the surface shall not exceed the values specified in Table 1806.2 unless data to substantiate the use of higher values are submitted and approved. Where the building official has reason to doubt the classification, strength or compressibility of the soil, the requirements of Section 1803.5.2 shall be satisfied.
Presumptive load-bearing values shall apply to materials with similar physical characteristics and dispositions. Mud, organic silt, organic clays, peat or unprepared fill shall not be assumed to have a presumptive load-bearing capacity unless data to substantiate the use of such a value are submitted.
|CLASS OF MATERIALS||VERTICAL FOUNDATION|
|LATERAL BEARING |
(psf/ft below natural grade)
|LATERAL SLIDING RESISTANCE|
|Coefficient of frictiona||Cohesion (psf)b|
|1. Crystalline bedrock||12,000||1,200||0.70||—|
|2. Sedimentary and foliated rock||4,000||400||0.35||—|
|3. Sandy gravel and/or gravel (GW and|
|4. Sand, silty sand, clayey sand, silty|
gravel and clayey gravel (SW, SP, SM, SC,
GM and GC)
|5. Clay, sandy clay, silty clay, clayey silt, silt |
and sandy silt (CL, ML, MH