Torsion Flashcards
The ___________ is largely
subjected to torsion, some bending
and shear due to own weight.
cantilever member
______ subjected to torsion, in
combination with bending and shear.
RC members
The __________ is subjected to
substantial amounts of bending,
shear and torsion.
fixed-ended beam
Spandrel beams at the edge of a building built integrally with the
floor slab are subjected not only to __________ but also to a
torsional moment per unit length equal to the restraining moment at
the exterior end of the slab.
transverse loads
__________ receive torsional moments from the
exterior ends of the floor beams that frame into them.
spandrel girders
Torsion on structural systems may be classified into two types:
statically determinate torsion (“equilibrium torsion”)
Statically indeterminate torsion (compatibility torsion”)
Torsion can be determined from statics alone
statically determinate torsion
Torsion cannot be determined from statics alone and a ________ is
required for deformational compatibility between interconnecting elements, such as a spandrel beam, slab, or column.
Statically indeterminate torsion , rotation (twist)
Linear interpolation
between 0.75 and 0.85 shall be permitted, on the basis of _______, when a portion of
the lightweight fine aggregate is replaced with normal weight fine aggregate.
volumetric fractions
Linear interpolation between ____ and ______ shall be permitted, on the basis of volumetric fractions, for concrete
containing normal weight fine aggregate and a blend of lightweight and normal weight coarse
aggregates.
0.85 and 1.0
Torsion occurs appreciably in many structures, such as in the main
girders of bridges, which are twisted by ______ beams or slabs.
transverse
If a plain concrete member is subjected to pure torsion, it will
crack and fail along ________ due to diagonal tension
corresponding to the torsional stresses.
45° spiral lines
Maximum shears and torsional forces may occur in areas where
bending moments are _____.
small
_______ is assumed to occur when the principal tensile stress reaches 0.33A.
Cracking
In a __________ loaded with torsion alone, the
principal tensile stress is equal to the torsional shear stress,
nonprestressed beam
For a statically determinate structure, there is only one path along which a
torsional moment can be transmitted to the supports. T or F
T
The _________ in a particular part of a statically indeterminate
structure may be substantially reduced if that part of the structure cracks
under torsion and/or rotates.
torsional moment
__________, in the sense that part of structure in
question twists in order to keep the deformations of the structure
compatible.
compatibility torsion
When appreciable torsion is present, it may be more economical to
select a _______ than would normally be selected so that torsional
reinforcement does not have to be used.
larger beam
The _________ adds to the shear stress on one side of
a member and subtract from them on the other.
torsional stress
Torsional stresses are quite low near the ______ of a
solid beam.
center
_________ are assumed to
have almost exactly the same torsional strengths as solid
beams with the same outside dimensions
hollow beams
The tension cracks tend to spiral around members located at
approximately ______angles with the longitudinal edges of those members.
45°
Torsion is assumed to be resisted by an imaginary ___________ located in
the outer tube of concrete of the member.
space truss
torsional strength of reinforced concrete beams can be
greatly increased by adding __________ consisting
of closed stirrups and longitudinal bars.
torsional reinforcement
It shall be permitted to take 0 equal to 45° for
_________ members.
nonprestressed
The longitudinal reinforcement required for torsion must be
distributed around the inside perimeter of the closed stirrups with a
maximum spacing of ________.
300 mm
Longitudinal bars shall
have a diameter at least ______times the stirrup spacing, but not less
than No. 10.
0.042 ,
Torsional reinforcement must be provided for a distance not less than
_______ beyond the point where it is theoretically no longer required.
bt + d
