The provisions of Section 1808 of IBC are adopted by reference with the following modifications:
1. Revise Section 1808.1 to read:
"1808.1 General.
Foundations shall be designed and constructed in accordance with Sections 1808.2 through 1808.9. Shallow foundations shall also satisfy the requirements of Section 1809. Deep foundations shall also satisfy the requirements of Section 1810."
2. Revise Section 1808.2 to read:
"1808.2 Design for capacity and settlement.
Foundations shall be so designed that the allowable bearing capacity of the soil is not exceeded, and that differential settlement is minimized. Foundations in areas with expansive soils or fills shall be designed in accordance with the provisions of Section 1808.6. Analysis shall consider soil layers underlying the designated load-bearing layer."
3. Add a new Section 1808.2.1 to read:
"1808.2.1 Factor of safety.
Foundation elements shall develop a minimum factor of safety against bearing capacity of 3.0 when routine testing is used to determine soil properties. Foundation elements shall develop a minimum factor of safety of 2.5 against bearing capacity failure when in-situ testing is used to determine soil properties."
4. Revise Section 1808.6 to read:
"1808.6 Design for expansive soils or fills.
Expansive soils or fills shall be removed in accordance with Section 1808.6.3."
5. Delete Section 1808.6.1.
6. Delete Section 1808.6.2.
7. Revise Section 1808.6.3 to read:
"1808.6.3 Removal of expansive soil or fill.
Where expansive soil or fill is removed, the soil shall be removed to a depth sufficient to ensure a constant moisture content in the remaining soil or fill. Newly placed fill material shall not contain expansive soils or fill and shall comply with Section 1804.5 or 1804.6.
Exception: Expansive soil or fill need not be removed to the depth of constant moisture, provided that the confining pressure in the expansive soil or fill created by the newly placed fill material and supported structure exceeds the swell pressure."
8. Revise Section 1808.6.4 to read:
"1808.6.4 Stabilization.
Where the active zone of expansive soils or fill is stabilized in lieu of designing foundations in accordance with Section 1808.6.1 or 1808.6.2, the soil or fill shall be stabilized by chemical, dewatering, presaturation or equivalent techniques."
9. Delete Section 1808.7 and its subsections.
10. Delete Figure 1808.7.1.
11. Revise Table 1808.8.1 by replacing "Seismic Design Category D, E or F" with "Seismic Design Category D."
12. Revise row 4 of Table 1808.8.1 to read "4. Drilled shafts and auger cast piles."
13. Revise the second and third sentences of Section 1808.8.3 to read:
"1808.8.3 Placement of concrete.
Concrete shall not be placed through water unless a tremie or other approved method is used. Where placed under or in the presence of water, the concrete shall be deposited by means to ensure minimum segregation of the mix and negligible turbulence of the water."
14. Revise Section 1808.8.6 by replacing "Seismic Design Category C, D, E or F" with "Seismic Design Category C or D"; Seismic Design Category D, E or F" with "Seismic Design Category D" and "Detached one- and two- family dwellings" with "Group R-5 occupancies."
(Amend Coun. J. 2-19-20, p. 14473, Art. II, § 80)