Subsoil class (see table 7)

S

β₀

T_B

T_C

T_D

A

1.0

2.5

0.1

0.4

3.0

B

1.0

2.5

0.15

0.6

3.0

C

0.9

2.5

0.2

0.8

3.0

Subsoil class (see table 7)

k_d1

k_d2

A

2/3

5/3

B

2/3

5/3

C

2/3

5/3

Subsoil class

Descriptions

A

Rock or other geological formation characterized by a shear wave velocity vs of at least 800 m/s, including at most 5 m of weaker material at the surface.

Stiff deposits of sand, gravel or over-consolidated clay, at least several tens of m thick, characterized by a gradual increase of the mechanical properties with depth and by vs-values of at least 400 m/s at a depth of 10 m.

B

Deep deposits of medium dense sand, gravel or medium stiff clays with thickness from several tens to many hundreds of m, characterized by vs-values of at least 200 m/s at a depth of 10 m, increasing to at least 350 m/s at a depth of 50 m.

C

Loose cohesion-less soil deposits with or without some soft cohesive layers, characterized by vs-values below 200 m/s in the uppermost 20 m.

Deposits with predominant soft-to-medium stiff cohesive soils, characterized by vs-values below 200 m/s in the uppermost 20 m.