Civil Engineering Reference
In-Depth Information
A second-degree polynomial equation is fitted in the |
% error
| for each parame-
ter. The polynomial fit represents the average |
% error
| trend for the available com-
parisons. Polynomials,
for the most part, show |
% error
|, under 20%, with many
comparisons showing |
% error
| below 10%. The polynomials for all equations are
clustered together indicating that all equations yield similar accuracy.
The cell properties do not appear to have an effect on the |
% error
|. For exam-
ple the error trend for
I
c
/I
b
and
L
c
/L
b
is flat. Similarly the number of bays,
b
, has
no effect on the error trend. The building aspect ratio has a small effect on the
computed error with buildings having
H/L
= 2-4 showing a slightly smaller error
trend. Likewise the location where the lateral drift is being computed (
i/s
) has a
small effect on the |
% error
|. The number of stories,
s
, has a noticeable effect on
|
% error
|, with one story buildings exhibiting the most error. This is not surprising
since these structures may exhibit some flexure deflection that is not accounted for
in the formulation. In any case, the error is not large, and there are convenient
methods of estimating the deflection of single story frames.
3.6 Examples
Several examples are presented to aid the reader in applying the derived equations in
everyday situations (Table 3.5). The examples are chosen such that the parameters
employed are different from those used to calibrate the equations.
Table 3.5
Parameters used in Examples
Example 1
Example 2
Example 3
Units
Loading Type
Uniform
Wind or Seismic
Earth
Maximum Lateral Stress
Psf
250
100
1480
No. of Bays,
b
…
4
6
10
No. of Stories,
s
…
4
20
4
Height of Column,
L
c
ft
10
10
9
Length of Beam,
L
b
ft
10
12.5
15
Column Dimensions (
b
x
d
)
ft
12 x 12
20 x 20
16 x 16
Wall Dimensions (
t
x
d
)
ft
…
…
12 x 180
Beam Dimensions (
b
x
d
)
ft
12 x 12
16 x 24
12 x 20
ft
4
Inertia of Column,
I
c
0.0833
0.643
0.2633
ft
4
1.25
Inertia of Wall,
I
wall
…
…
ft
4
0.3858
Inertia of Beam,
I
b
0.0833
0.888
Shear Modulus,
G
ksf
216000
216000
216000
Frame Spacing
ft
10
12.5
15
