Civil Engineering Reference
In-Depth Information
TABLE 14.10
Lateral Soil Load
Design lateral soil load
a
(pounds per square foot
per foot of depth)
Unified soil
classification
system
Active
At-rest
Description of backfill material
c
pressure
pressure
Well-graded, clean gravels; gravel-sand mixes
GW
30
60
Poorly graded clean gravels; gravel-sand
GP
30
60
mixes
Silty gravels, poorly graded gravel-sand
GM
40
60
mixes
Clayey gravels, poorly graded gravel-and-
GC
45
60
clay mixes
Well-graded, clean sands; gravelly sand
SW
30
60
mixes
Poorly graded clean sands; sand-gravel mixes
SP
30
60
Silty sands, poorly graded sand-silt mixes
SM
45
60
Sand-silt clay mix with plastic fines
SM-SC
45
100
Clayey sands, poorly graded sand-clay
SC
60
100
mixes
Inorganic silts and clayey silts
ML
45
100
Mixture of inorganic silt and clay
ML-CL
60
100
Inorganic clays of low to medium plasticity
CL
60
100
Organic silts and silty clays, low plasticity
OL
Note b
Note b
Inorganic clayey silts, elastic silts
MH
Note b
Note b
Inorganic clays of high plasticity
CH
Note b
Note b
Organic clays and silty clays
OH
Note b
Note b
For SI: 1 pound per square foot per foot of depth
304.8 mm.
a. Design lateral soil loads are given for moist conditions for the specific soils at their optimum densities. Actual
field conditions shall govern. Submerged or saturated soil pressures shall include the weight of the buoyant
soil plus the hydrostatic loads.
b. Unsuitable as backfill material.
c. The definition and classification of soil materials shall be in accordance with ASTM D 2487 (Unified Soil
Classification System).
Source:
0.157 kPa/m. 1 foot
Table 1610.1 of the
International Building Code
(2012). See also Table 14.9.
14.2.7 Site Class
An important parameter in geotechnical earthquake engineering is the site class and it is
defined as a classification assigned to a site based on the types of soil present and their
engineering properties. The geotechnical engineer is the best individual to determine the
site class. Section 1613.3.2 of the
International Building Code
(2012) states that based
on the site soil properties, the site should be classified as site class A, B, C, D, E, or
F in accordance with Chap. 20, “Site Classification Procedure for Seismic Design,” of
ASCE Standard 7-10
Minimum Design Loads for Buildings and Other Structures
(2010).
The
International Building Code
also states: “Where the soil properties are not known in
