1803.2.2 Seismic Design Category D.
BC § 1803.2.2
For structures assigned to Seismic Design Category D in accordance with Section 1613, the geotechnical investigation shall meet the requirements of Section 1803.2.1 and the following as applicable: 1. A determination of dynamic seismic lateral earth pressures on foundation walls and retaining walls supporting more than 6 feet (1828.8 mm) of in situ soil or backfill height due to design earthquake ground motions. Peak ground acceleration for use in lateral pressure analyses shall be determined in accordance with Section 1816.2.1.
2.The potential for liquefaction and soil strength loss evaluated for site peak ground acceleration, earthquake magnitude and source characteristics consistent with the maximum considered earthquake ground motions. Peak ground accelerations for use in such analyses shall be determined in accordance with Section 1816.2.1.
3.An assessment of potential consequences of liquefaction and soil strength loss including, but not limited to, the following: 3.1. Estimation of differential settlement. 3.2. Lateral soil movement. 3.3. Lateral soil loads on foundations. 3.4. Reduction in foundation soil-bearing capacity and lateral soil reaction 3.5. Soil downdrag and reduction in axial and lateral soil reaction for pile foundations. 3.6. Increases in soil lateral pressures on retaining walls. 3.7. Flotation of buried structures.
4.Discussion of mitigation measures such as, but not limited to, the following: 4.1. Selection of appropriate foundation type and depths. 4.2. Selection of appropriate structural systems to accommodate anticipated displacements and forces. 4.3. Ground stabilization. 4.4. Any combination of these measures and how they shall be considered in the design of the structure.
