What site class designation corresponds to rock?

The correct designation for rock is Site Class B. Site Class B is typically assigned to sites that consist of competent and stable bedrock, which has a high shear wave velocity, generally greater than 1,200 meters per second. This classification is essential for seismic design as it indicates lower vulnerability to earthquake shaking compared to softer or unconsolidated materials.

Understanding site class designations is crucial for professionals involved in geotechnical engineering and seismic assessments because they influence design criteria for structures in earthquake-prone areas. Site Class A, on the other hand, corresponds to sites with very hard rock, while Site Class C refers to dense soil and soft rock. Site Class D includes softer soils that can amplify seismic waves, making it less suitable for structures in seismic zones.