What classification is used for soil or soft rock with shear wave velocity between 1200-2500 ft/s?

The classification of soil or soft rock with a shear wave velocity between 1200-2500 ft/s falls under Site Class C according to the criteria established in the California Building Code and related seismic design standards. Site Class C is characterized by soils that are generally stiff, such as dense sand or very soft rock, which can still exhibit significant structural response during seismic events.

This classification is important for engineering and construction purposes, as it helps determine the seismic response of the site and the necessary design criteria for buildings and other structures. Site Class C indicates moderate to high ground shaking potential during an earthquake, which directly influences the design specifications that engineers must follow to ensure safety and stability.

The other site classes serve different ranges of shear wave velocities and physical properties. Site Class B refers to deeper, stiff soils or hard rock with higher shear wave velocities (greater than 2500 ft/s), while Site Class A is reserved for very hard rock with a shear wave velocity exceeding 5000 ft/s. Site Class D describes medium to soft soils with lower shear wave velocities (typically below 1200 ft/s). Thus, Site Class C is the most appropriate designation for materials within the specified velocity range of 1200-2500 ft/s.