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REBAR AREA FROM REBAR NUMBERS
Nos. Rebar Dia Total Rebar Area
6 14 923.63 mm2
0 14 0.00 mm2
0 8 0.00 mm2
Total 0 mm2
Beam Rebar Area
No. Sraight Area Total
2 25 490.87 981.75
No. Extra Area Total
Ok
1 8 50.27 50
0 8 50.27 0
Grand Total 1032
22900
76.333333
655 81.875
500
925
8
10
12
14
16
18
20
22
25
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0.76 0.79 0.79 0.5
0.32 0.28 0.34 1.25 1.2
0.34 1.4
0.62 0.62
2- Y16 2- Y16
Extra 1- Y16 Extra 1- Y16
0.62 0.62
2- Y16 2- Y16
0 Y16 Extra 3- Y16
0.5 0.5 0.5 0.5
1.4 0.28 0.18 0.27 http://docs.csiamerica.com/manual
0.28
0.62 0.62
2- Y16 2- Y16
0 Y16 0 Y16
0.62
2- Y16
0 Y16
As "Tcr" and "Tu" given therein are indeed threshold
respectively, and are both design properties not
11.5.1
Whereas the torsional constant, ETABS asks in "ana
torsional moment of inertia (J) used to determine tors
else.
As long as its value is concerned,then in building stru
value like .001 to nullify beam's torsional stiffness.In
compatibility of deformation i.e compatibility torsio
redistribution of torsional moments occurred), cons
restraint and in other condition if torsional stresse
structure (where redistribution is not possible) then to
of whatever value of "J" you have selected as eq
independent of stiffness as "Compatibility is
This approach of minimization of "J" economize beam
and torsion requirement of building codes,but conse
start developing internal horizontal cracks (hairline c
to torsional stresses and their torsional strength will
achieved i.e negligible torsional strength of beam.But
torsional stiffness of beam so it remain stable after
member itself cracks that doesn't affect th
A very descriptive and clarifying description is availa
by Arthur Nilson".
As long as authentication of this approach is conce
codes as,
1, ACI-318-11 section 11.5.2.
2, UBC97 section 1911.6.2.1
3, BS 8110-1 1997 section
Keeping in view above mentioned, it is a general pra
beams in building structures and it is not required to
torsional constant of each beam section that is ind
thousands of beam span in lar
14
s.csiamerica.com/manuals/etabs/Concrete%20Frame%20Design/CFD-ACI-318-14.pdf 16
18
20
22
25
28
30
herein are indeed threshold torsional strength and ultimate torsional stresses
both design properties not analysis properties. (See ACI 318-11 section
11.5.1).
onstant, ETABS asks in "analysis property modification factors" is simply the
ia (J) used to determine torsional stiffness of a member (JG/L) i.e something
else.
ncerned,then in building structures it is a general practice to use a negligible
beam's torsional stiffness.In this way, the torsional stresses (if arising due to
mation i.e compatibility torsion ) are transferred via alternate load path (i.e
al moments occurred), considering that beam is unable to provide torsional
condition if torsional stresses in beam is required to satisfy equilibrium of
bution is not possible) then torsional stresses in beams remains independent
"J" you have selected as equilibrium equations are necessarily satisfied
stiffness as "Compatibility is optional and equilibrium is essential".
zation of "J" economize beam sizes that arise from stringent combined shear
of building codes,but consequently beam sections designed in this way will
horizontal cracks (hairline cracks not affecting functionality of structure) due
d their torsional strength will continuously degrade till the design condition is
rsional strength of beam.But as the structure is designed to be stable without
eam so it remain stable after this condition is achieved.However, the beam
cracks that doesn't affect the functionality of structure in any way.
larifying description is available in "Reinforced concrete design
by Arthur Nilson".
on of this approach is concerned then it is allowed by building
codes as,
ACI-318-11 section 11.5.2.1 & 11.5.2.2.
UBC97 section 1911.6.2.1 & 1911.6.2.2
3, BS 8110-1 1997 section 3.4.5.13
mentioned, it is a general practice to nullify torsional constant of
ures and it is not required to use any iterative process to derive
ach beam section that is indeed not practical as there will be
ousands of beam span in large structures.
