Civil Engineering Reference
In-Depth Information
Values for spring coefficient for rocking motion—and for other spring coefficients
for other types of motion—should be determined from soil data for accurate design. If
no reliable soil data is available, coefficients and can be estimated using the
third column in Table 3.4, where
k
s
is the modulus of subgrade reaction (also called
'dynamic subgrade reaction' or 'coefficient of elastic uniform compression').
using Barkan's [1962] data.
If reliable soil information is available, the procedures outlined in
[Richart, Woods and Hall, 1970] can be used for determining more accurate
spring constants and coefficients for the analysis of vertical and rocking
motions.
After substituting for the spring constant in the moment equilibrium equation
and taking into consideration that sin
α
/
α
=1 holds at
α
=0, the sway critical load
of the stiff column on flexible support is obtained as
