Column Design-Unaixial Bending
Column Design-Unaixial Bending
Column Design-Unaixial Bending
y
B = 4000 mm
D = 5000 mm
Axial Force = 1000 kN
Moment in One Direction = 500 kNm
Area = 20000000 mm^2
Dia of Steel in Compression = 25 5m
Number of bars in Compression 25
Dia of Steel in Tension = 20
Number of bars in Tension = 25
Ast C = 12271.8463
Ast T = 7853.98163
Ast = 20125.8 mm^2 x
Ac = 19979874 mm^2
Grade of Concrete = 40 Mpa
Grade of Steel = 500 Mpa
4m
Es = 2.00E+05 Mpa
Ec = 3.30E+04 Mpa
Modular Ratio m = 6.06E+00
Trail Xu Assumed = 2500 mm
Clear Cover 50 mm
d' 62.5 mm
Effective Depth 4937.5 mm
H/2 2500
Aeff = Area of Concrete in com + Area of Steel in Comp + Area of Steel in Tension
= 10000000 + 6.21E+04 + 4.76E+04
= 10109702.87 mm^2
Calculation of Effective CG
e-e' = 4.99E+05 mm
For this location of Xu the strain and corresponding stresses at different level of steel are
Now, Axial and moment resistance from the steel can be calculated as follows
Y d' (m) Strain ϵyd Stress Comp./ φ mm Number Area φ Number Area Nrd L.A @c.g Mrd
Tens.
1 83.000 0.002096 0.002175 419.18 Comp 16 6 1206.37 0 0 0.00 5.06E+05 3.67E+02 1.86E+08
2 817.000 0.010321 0.002175 434.78 Tension 25 6 2945.24 25 6 2945.24 -2.56E+06 -3.67E+02 -9.40E+08
No.of bars 12 4151.61 6
Total -2.06E+06 -7.54E+08
1000 mm
d'
Asc
900 mm
Ast
d''
Design Data
Moment = 900.00 KN-m
Axial Load = 1000.00 KN
Asc = 1206.371579 mm2
Ast = 5890.4862255 mm2
B = 1000 mm
D = 900 mm
Max. Dia at top = 16 mm
Max. Dia at bottop = 25 mm
Clear cover = 75 mm
d' Comp = 83 mm
d'' Tension = 87.5 mm
m = 6.06E+00
X = 206.894 mm
Step 4
Distance of CG eff from physical centroid
e' = 71699747.2837 + 2240524.4759 - 12941219.738
248698.93269
= 245.27267312 mm
y = 93.8462996588 mm
= 3.61883338333 + 7.894547656
= 11.5133810393 N/mm2 < 16.8 Mpa
= 21.9323235353 - 142.03934467
= -120.10702113 N/mm2 < 400 Mpa