3

oblem 3. (25%) For this problem you must use length-L from (ONLY) the last 3 digits of your Eagle ID (write it here):

length of column) = 125 (in inches, last 3 digits of Eagle ID; any value smaller than “100" will be “100 inch“)

Problem 3. A column of length L (see above) has TWO FIXED-RIGID-ends and is made of a C-shape C15x33.9 (SEE TABLE

BELOW for all section data); material is steel with elastic limit (at compression) of 30ksi, and E = 29 x10³ ksi.

Note: this is NOT

3.(a). Determine the maximum load than can be applied before it either buckles or fails by compression.

the column, but the

section used

Columis shown

below

Lby

American Standard Channels or C Shapes FPS Units

Flange

Designation A

in²

14.7 15.00

in. x lb/ft

C15 x 50

CH

C15 x 33.9

Perit

L

7777

Area Depth

d

20

F3

in.

9.96 15.00

$

4

Web

thickness

tw

in.

ANSWER to 3.(b) *MUST* be in here (CHECK correct one):

larger,

smaller,

the same

DOC

000

F4

width

be

in.

ANSWER to 3.(c) *MUST* be in here (CHECK correct one):

larger,

smaller,

the same

X

%

thickness

t

0.716 11/16 | 3.716 | 3

3.716 3 0.650 5/8 404

10539

548 349

5/8 315

0.400 3/8 3.400 3 0.650

3.(b). If the column of 3.(a) (above) were fixed at one end, and with free (no support) at the other end, the Critical Load

would be, as compared to 3(a) above: larger, or smaller, or the same?

F5

3.(c). If the COMPRESSIVE LOAD (FORCE) of column in 3.(b) (immediately above) WERE APPLIED at the free end WITH A

10-inch ECCENTRICITY (from section centroid), the Critical Load would be, as compared to 3.(b) (immediately above):

larger, or smaller, or the same?

&

f

inª

F7

X-X axis

S

in³

53.8 5.24 11.0

544

42.0 5.62 8.13 3.11 0.904

ř

DII

F8

in.

1

y-y axis

S

in³

3.78 0.867

F9

in.

1

F10

F11