Design of Compression Members Flashcards
(27 cards)
The selection of an economical rolled shape to resist a given
compressive load is simple with the aid of the column load
tables.
Design
In some cases, the search may continue until the_______-shape
is found
lightest
For shapes not in the column load tables, a ______-
approach must be used.
trial-and-error
If a compression member is supported differently with respect
to each of its principal axes, the ________- will be
different for the two directions.
effective length
All compression members so far are treated as _______-.
pin-ended
Generally speaking, a______ or _____, condition is very difficult
to achieve, and unless some special provisions are made,
ordinary connections will usually closely approximate a ________ or _______.
rigid, or fixedhinge or
pin connection
_________ decreases with increasing KL/r, a column
will ________ in the direction corresponding to the largest
slenderness ratio
Column strength, buckle
Whenever possible, the designer should provide _______ for
the weak direction of a column
extra support
the _________– provided by the beams, or girders, at
the end of a column is a function of the rotational stiffnesses
of the members intersecting at the joint
rotational restraint
__________ depends on the ratio of column
stiffness to girder stiffness at each end of the member
effective length factor K
due to bending or
flexure about the axis with largest slenderness ratio; usually
the minor principal axis (with smallest r)
Flexural buckling
twisting about the longitudinal axis;
occur only with doubly symmetrical cross sections with very
slender elements; standard hot-rolled shapes not susceptible
but members built up from thin plate elements
Torsional buckling
member bends and twists
simultaneously; occur only with unsymmetrical cross sections
i.e. C, T, 2L and equal leg L and no axis of symmetry
(unequal leg L)
Flexural-torsional buckling
can be defined as the elastic
buckling stress corresponding to the controlling mode of failure,
whether flexural, torsional, or flexural-torsional
Fe
For__________ sections, Cw may be taken as
Iyho^2/4, where ho is the distance between flange centroids, in lieu of
a more precise analysis
doubly symmetric I-shaped
warping constant, mm6
Cw
For ____ and ______, omit the term
with Cw when computing Fez and take xo as 0.
tees and double angles
The need for a torsional buckling analysis of a _________ shape will be rare.
doubly
symmetrical
________- can be used for double angles
and tees
column load tables
Column load tables give two sets of values of the available
strength, one based on _______________ and
one based on_____________-
flexural buckling about the x-axis, flexural-torsional buckling about the y-axis
For__________, the tables are not based on
flexural-torsional buckling theory, but on the provisions of
NSCP 505.5/AISC E5
single-angle members
For _________-, no need to account for slender
compression elements (already been done) in using the column
load tables
unsymmetrical shapes
_________ (rolled shapes) is the most common built-up
shape
double-angle
________- must ensure that the built-up member acts as a
unit
connection
