Compression Members

Question 1

structural elements subjected only to axial compressive forces,
i.e. loads are applied along a longitudinal axis through the
centroid of the member cross section

Answer 1

Compression members

Question 2

most common type of compression member

Answer 2

column

Question 3

if column is
subjected to bending, it is called ________

Answer 3

beam-column

Question 4

smaller compression member not classified as column

Answer 4

strut

Question 5

If the axial load P is slowly applied, at
large value it will cause the member to
become unstable and assume the shape
(dashed line). The member is said to have
buckled, and the corresponding load is
called ___________

Answer 5

critical buckling load

Question 6

For stocky member, a larger load is needed
for instability. For extremely stocky
member, failure by __________ will
occur not buckling

Answer 6

compressive yielding

Question 7

The load at which buckling occurs is a function of _________

Answer 7

slenderness

Question 8

is the slenderness ratio and is the measure of a
member’s slenderness, with large values corresponding to slender
members

Answer 8

L/r

Question 9

__________ causes a large buckling
stress

Answer 9

small slenderness

Question 10

____________ occurs beyond the proportional
limit, stress and strain relation is not linear

Answer 10

buckling

Question 11

__________ proposed the
use of variable tangent modulus, Et
, for
values of f between Fpl and Fy.

Answer 11

Friedrich Engesser

Question 12

completely describes the
strength of any column of a
given material.

Answer 12

column strength curve

Question 13

________ is a function
only of the slenderness ratio.

Answer 13

strength

Question 14

For members designed on the basis of compression, the effective
slenderness ratio KL/r preferably should not exceed ______

Answer 14

200

Question 15

sum of the factored
loads

Answer 15

Pu

Question 16

resistance factor for
compression

Answer 16

0.90

Question 17

sum of the service
loads

Answer 17

Pa

Question 18

safety factor for
compression

Answer 18

1.67

Question 19

design compressive
strength

Answer 19

φcPn

Question 20

allowable
compressive strength

Answer 20

Pn/Ωc

Question 21

______ shall be the lowest value obtained according to
the limit states of flexural buckling, torsional buckling and
flexural-torsional buckling

Answer 21

Pn

Question 22

___________
shall be determined based on the limit state of flexural buckling.

Answer 22

nominal compressive strength,

Question 23

AISC does not require an upper limit on the slenderness ratio
KL/r, but an upper limit of ______ is recommended.

Answer 23

200

Question 24

_________________ are efficient shapes for
compression members because ry = rx and the strength is the
same for both axes

Answer 24

square structural tubes (HSS)

Question 25

__________ are sometimes used as compression members for the same reason above

Answer 25

hollow circular shapes

Question 26

the member is subjected to____ or_____, when it becomes unstable.

Answer 26

flexure or bending

Question 27

for elements with thin cross section ___________

Answer 27

local buckling occurs

Question 28

if ___________ occurs, the cross-section is no longer fully effective and the member has failed

Answer 28

instability

Question 29

___________ cross sections with thin flanges or webs are susceptible (the use of this should be avoided if possible or the compressive strength must be reduced)

Answer 29

I–shaped

Question 30

unsupported along one edge parallel to the direction of load

Answer 30

unstiffened elementsq

Question 31

supported along both edges

Answer 31

stiffened elements

Question 32

its strength limit state is local buckling and the corresponding reduced strength must be computed

Answer 32

Slender

Question 33

for a section to qualify as __________ its flanges must be continuously connected to the web(s) and the width-thickness ratios of its compression elements must not exceed the limiting width-thickness ratios λp from

Answer 33

compact

Question 34

if the width-thickness ratio of one or more compression elements exceeds λp, but does not exceed λr

Answer 34

Noncompact

Question 35

if the width-thickness ratio of any element exceeds λr

Answer 35

Slender-element

Question 36

the strength could be reduced because of _________

Answer 36

local buckling

Question 37

Q = ______ for members with compact and noncompact sections

Answer 37

1.0

Question 38

Q = ______ for members with slender-element sections.

Answer 38

QsQa

Question 39

________ for unstiffened elements

Answer 39

Qs

Question 40

_______- for stiffened elements

Answer 40

Qa

Question 41

many of the shapes commonly used as columns are not slender, thus, reduction is not needed, that includes most (but not all) _______

Answer 41

W-shapes.

Question 42

summation of the effective areas of the cross section based on the reduced effective width, be, mm2

Answer 42

Aeff