OTHER GEOTECHNICAL EARTHQUAKE ENGINEERING ANALYSES - Geotechnical Earthquake Engineering - page 363

TABLE 11.1 Soil Profile Types

Average soil properties from ground surface to a depth of 100 ft (30 m)

Granular soil: Cohesive soil:

Soil Shear wave velocity ( N 1 ) 60 value undrained shear

profile Material V s 1 [see Eq. (6.9)], [see Eq. (5.2)], strength s u ,

lb/ft 2 (kPa) type descriptions ft/s (m/s) blows per foot

S A Hard rock 5000 ( 1500) — —

S B Rock 2500 -5000 (760 -1500) — —

S C Soft rock, very 1200 -2500 (360 -760) 50 2000 ( 100)

dense granular soil,

very stiff to hard

cohesive soil

S D Dense granular soil, 600 -1200 (180 -360) 15-50 1000 -2000 (50 -100)

stiff cohesive soil

S E * Granular soil having 600 ( 180) 15 1000 ( 50)

a loose to medium

density; cohesive

soil having a soft

to medium

consistency

S F Soil requiring a site-specific evaluation (see Sec. 11.5.2)

*Soil profile S E also includes any subsoil profile having more than 10 ft (3 m) of soft clay, defined as a soil with
a plasticity index 20, water content 40 percent, and s u 500 lb/ft 2 (24 kPa).
Data obtained from the Uniform Building Code (1997).

site. The Uniform Building Code (1997) also provides the seismic zone values for other
countries. A response spectrum would usually not be needed for sites that have a
seismic zone 0.
2. Soil profile type: Using Table 11.1, the next step is to determine the soil type profile
(i.e., S A , S B , S C , S D , S E , or S F ), as follows:
a. Soil profile types S A , S B , S C , and S D : For the first four soil profile types, the classi-
fication is based on the average condition of the material that exists at the site from
ground surface to a depth of 100 ft (30 m). If the ground surface will be raised or
lowered by grading operations, then the analysis should be based on the final as-built
conditions. As indicated in Table 11.1, the selection of the first four soil profile types
is based on the material type and engineering properties, such as shear wave veloc-
ity, standard penetration test ( N 1 ) 60 values, and the undrained shear strength.
b. Soil profile type S E : Similar to the first four soil profiles, the classification for S E is
based on material type and engineering properties, such as shear wave velocity, stan-
dard penetration test ( N 1 ) 60 values, and the undrained shear strength. In addition, any
site that contains a clay layer that is thicker than 10 ft and has a plasticity index 20,
water content 40 percent, and undrained shear strength s u 500 lb/ft 2 (24 kPa)
would be considered to be an S E soil profile.
c. Soil profile type S F : The definition of this last soil profile is as follows:
● Soils vulnerable to potential failure or collapse under seismic loading such as liquefi-
able soil, quick and highly sensitive clays, and collapsible weakly cemented soils.