Shear - Tensile -

shrubflattenUrban and Civil

Nov 25, 2013 (3 years and 6 months ago)

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Shear
-

Tensile
-

Compression Stresses

Slip

Ted 126

Spring 2007

Shear


Shear strength in mechanical engineering and
structural engineering is a term used to describe
the strength against the type of structural failure
where a component fails by shearing when it splits
into two parts that slide past each other.


The shear strength of a component is most
important for beams but also relevant for e.g.
plates.


In a reinforced concrete beam, the main purpose of
stirrups is to increase the shear strength.

Shear


Riveted and bolted joints may also be mainly
subjected to shear stress.



Cantilevers, beams, consoles and column heads are
subject to composite loading, consisting of shear,
tensile and compressive stress.

Tensile stress


Tensile stress

(or tension) is the stress state
leading to expansion; that is, the length of a
material or compression member tends to increase
in the tensile direction.


Tensile stress

is the opposite of compressive
stress.


Structural members in direct tension are
ropes
,
soil anchors

and
nails
,
bolts
,
etc
.


Beams subjected to bending moments may include
tensile stress as well as compressive stress and/or
shear stress
.

Tensile Strength


The
tensile strength

of a material
is the maximum amount of tensile
stress that it can be subjected to
before failure.



The definition of failure can vary
according to material type and
design methodology.

Compressive stress


… applies to materials resulting in
their compaction (decrease of
volume).


When a material is subjected to
compressive stress

then this material
is under compression.


Usually compressive stress applied
to
bars
,
columns
, etc. leads to
shortening.

Slip


A
slip joint

is a mechanical construction
allowing extension and compression in a
linear structure.



A
slip
-
critical joint
, from structural
engineering, is a
joint which relies on
friction

(rather than shear or tensile
strength) to hold two things in place.

Slip



The
most common slip
-
critical joint

is where a
girder meets a larger beam.


Typically an angle plate joins the two.


One beam is welded to the angle plate, the other
has holes which are generally oversized or slotted.


The
bolt through this plate

doesn't actually take the
load as a shear joint or a bearing joint,


it simply creates normal force and therefore
friction between the two steel faces.