Overturning effects at the soil–foundation interface are permitted to be reduced by 10% for foundations of structures designed in accordance with the modal analysis requirements of Section 12.9.

The nominal foundation geotechnical capacity, Qns which is described in 12.13.5.1, is controlled by user. It’s taken into geotechnical report by users.

The resistance factors (ϕ), is controlled by user.


12.13.4 Reduction of Foundation Overturning

Overturning effects at the soil–foundation interface are permitted to be reduced by 10% for foundations of structures designed in accordance with the modal analysis requirements of Section 12.9.

12.13.5 Strength Design for Foundation Geotechnical Capacity

Where basic combinations for strength design listed in Chapter 2 are used, combinations that include earthquake loads, E, are permitted to include reduction of foundation overturning effects defined in Section 12.13.4.

The nominal foundation geotechnical capacity, Qns which is described in 12.13.5.1, is controlled by user.

12.13.5.2 Resistance Factors

The resistance factors is used for vertical, lateral, and rocking resistance of all foundation types. Nominal foundation geotechnical capacities, Qns, is multiplied by the resistance factors (ϕ) shown in Table 12.13-1.

12.13.5.3 Acceptance Criteria

For linear seismic analysis procedures, factored loads should not exceed foundation design strengths, ϕ*Qns.

12.13.9.1 Foundation Design

Foundations is designed to support gravity and design earthquake loads, as indicated in the basic load combinations of Section 12.4, using the reduced soil bearing capacity, as indicated in the geotechnical investigation report, considering the effects of liquefaction caused by MCEG earthquake motions.