Download - ACI318-08 Columna Rectangular Biaxial
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
1/45
P Mux Muy Vux Vuy B H cover
kN kN.m k N.m kN kN mm mm mm no. Dia no. Dia no. Dia spacing
1 1000 100 100 250 300 500 500 30 5 T 20 5 T 20 4 T 10 - 40
2 1000 137 142 150 113 500 500 30 5 T 20 5 T 20 4 T 10 - 40
3 1000 109 86 92 146 500 500 30 5 T 20 5 T 20 4 T 10 - 404 1000 89 147 110 80 500 500 30 5 T 20 5 T 20 4 T 10 - 40
5 1000 131 115 80 120 500 500 30 5 T 20 5 T 20 4 T 10 - 40
SectionHoriz. Rft. Vert. rft. Links
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
2/45
f Pn max (kN) f Mn (kN.m) f Vnx (kN) f Vny (kN) rmin rprov rmax Sx Sy3327.36 258.46 617.91 617.91 0.50% 2.05% 0.08 64 64 a
3327.36 259.25 617.91 617.91 0.50% 2.05% 0.08 64 64 a
3327.36 264.84 617.91 617.91 0.50% 2.05% 0.08 64 64 a3327.36 274.48 617.91 617.91 0.50% 2.05% 0.08 64 64 a
3327.36 261.55 617.91 617.91 0.50% 2.05% 0.08 64 64 a
strukts.comOutput results
Rem
arks
http://strukts.com/http://strukts.com/ -
7/30/2019 ACI318-08 Columna Rectangular Biaxial
3/45
5
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
4/45
-250 -250 -210 210 210 210 -210
250 -250 -210 140 210 140 -105
250 250 -210 70 210 70 0
-250 250 -210 0 210 0 105
-250 -250 -210 -70 210 -70 210
250 250 -210 -140 210 -140-250 -250
x1 -210
x2 210
spacing vertiv 70
y top 210
x -210
spacing horizo 105
y1 210
y2 -210
concrete right left to
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
5/45
210 -210 -210
210 -105 -210
210 0 -210
210 105 -210
210 210 -210
bottomp
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
6/45
DESIGN CODE
5 T 205 T20 BOTH SIDES
- egs
500 x 500C 05
ACI 318-08 CHECK. BY:
REVISION: A
C 05
DRAWING REFERENCE: REFERENCE
JOB REF: reference
RC rectangular column
PROJECT: Project
PART OF STRUCTURE: CALC. BY: Name
Name
Company logo
167169131.xls.ms_office STUKT strukts.com
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
7/45
DESIGN CODE
RECTANGULAR COLUMN DESIGN BASED ON ACI 318-08(ULTIMATE LIMIT STATE OF DESIGN)
INPUT DATA
MATERIALS PROPERTIESfc' = N/mm CONCRETE STRENGTH
fy = N/mm REBAR YIELD STRESS
CONCRETE DIMENSIONS
B = mm COLUMN WIDTH 30
H = mm COLUMN DEPTH
C = mm CONCRETE COVER
STEEL REINFORCEMENT
5 T COLUMN VERT. REINF. X dir. spacing = mm < mm (ACI 318-08, 7.10.5)
5 T COLUMN VERT. REINF. Y dir. spacing = mm < mm (ACI 318-08, 7.10.5)
T 10 @ 4 legs SHEAR REINF. in o.c., x dir.T 10 @ 4 legs in o.c., y dir
STRAINING ACTIONS
Pu = kN AXIAL
Mu,x = kN.m MOMENTS
Mu,y = kN.m
Vux = kN SHEARS
Vuy = kN
OUTPUT RESULTSCHECK FLEXURAL & AXIAL CAPACITY
Mu = kN.m (Mu,x2
+ Mu,y2
)0.5
(combined bending moments) q = 41 (the direction of combined load)Ag = mm
Ast = mm
f = (ACI 318-08, 9.3.2.2)
f Pn,ma = kN 0.8 f [0.85 fc' (Ag - Ast) + fy Ast] > Pu (at max axial load, ACI 318-08, 10.3.6.2)
f Mn = kN.m > Mu
rmin = < rprov. = < rmax = (ACI 318-08, 10.9)
CHECK SHEAR CAPACITY
f = (ACI 318-08, 9.3.2.3)
(ACI 318-08, 11.1.1) (ACI 318-08, 11.3.1) (ACI 318-08, 11.4.6.2)
smin = 25 mm < sprovd = mm < smax = mm (ACI 318-08, 7.10.4.3)
DESIGN SUMMARY FOR C 5FOR 5 500 x 500
PROVIDE 5 T 20 X-DIR., 5 T 20 Y-DIR.
f Mn (kN.m)
SECTION DIAGRAM INTRACTION DIAGRAM
40
fPn
(kN)
3.14E+02
d (mm)
437.2
437.2
A0 (mm2)
2.17E+05 3.14E+02
Av (mm2)
2.17E+05
Vc (0.17 (fc')^0.5A0)
164.77
164.77
320
174.32
0.005 0.020
245322
5026.55
0.65
f Vnf (Vs + Vc)
617.91
617.91
CHECK. BY: Name
y 659.10
Vs
659.10
30
dir.
x
CALC. BY:
500
JOB REF: reference
REVISION: A
PART OF STRUCTURE: RC rectangular column Name
PROJECT: Project
Company logoC 05
21
REFERENCE ACI 318-08DRAWING REFERENCE:
64
40
20
40
20 64
a
a
a
150 a
420
500
131
115
1000
150
a
a
a
261.55
0.75
80
120
3327.36
0.080
-100
0
100
200
300
400
500
600
700
800
050
100
150
200
250
167169131.xls.ms_office STUKT strukts.com
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
8/45
INPUT DATA & DESIGN SUMMARY
EFFECTIVE LENGTH FACTOR k = 1.6 , (ACI 10.12.1 or 10.13.1)
COLUMN UNSUPPORTED LENGTH Lu = 12 ftLARGER FACTORED MOMENT M2 = 200 ft-k
SMALLER FACTORED END MOMENT M1 = 100 ft-k, (positive if single curvature.)
CONCRETE STRENGTH f c' = 4 ksi
COLUMN DIMENSIONS h = 20 in
b = 20 in
FACTORED AXIAL LOAD Pu = 500 k
SUMMATION FOR ALL VERTICAL LOADS IN THE STORY S Pu = 1200 k
SUMMATION FOR ALL CRITICAL LOADS IN THE STORY S Pc = 13600 k, (ACI Eq. 10-10)
THE MAGNIFIED MOMENT: Mu = 236.7 ft-k , Sway
ANALYSIS
MAGNIFIED MOMENT - NONSWAY
r = 0.3 h = 6.0 in, ACI 10.11.2
k Lu / r = 38.4 > 34 - 12(M1 / M2) = 28 < = = Slenderness effect must be considered. (ACI 10.12.2)
Ec = 57000 (fc')0.5
= 3605.0 ksi, ACI 8.5.1
Ig = b h3
/ 12 = 13333 in4
1E+07 k-in2
, ACI 10.12.3
2234.2 k, ACI Eq (10-10)
M2,min = MAX[ M2 , Pu (0.6+0.03 h) ] = 200 ft-k, ACI 10.12.3.2
Cm = MAX[ 0.6 + 0.4 (M1 / M2, min) , 0.4 ] = 0.8 , ACI 10.12.3.1
1.14 , ACI Eq (10-9)
Mu, ns = dnsM2, min = 228.0 ft-k, ACI Eq (10-8) > 1.05M2 = 210.0 f t-k [Unsatisfactory] ,(ACI 10.11.4.1)
The column is sway. See calculation as follows.
MAGNIFIED MOMENT - SWAY
k Lu / r = 38.4 > 22 < = = Slenderness effect must be considered. (ACI 10.13.1)
1.13 , ACI Eq (10-18) & 10.13.6 (c)
Ag = b h = 400 in2
Lu / r = 24.00 < 35 / [Pu / (fc' Ag)]0.5
= 62.61 [Satisfactory] , (ACI 10.13.5)
M2s = M2 = 200.0 ft-k, as given
M2ns = 5% M2s = 10.0 ft-k, assumed conservatively
Mu, s = M2ns + dsM2s = 236.7 ft-k, ACI Eq (10-16)
Note: For column subject to bending about both principal axis, the moment about each axis shall be magnified separately based
on the conditions corresponding to that axis. (ACI 10.11.6)
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
9/45
INPUT DATA & DESIGN SUMMARY
CONCRETE STRENGTH f c' = 3.045 ksi
REBAR YIELD STRESS f y = 60.9 ksi
COLUMN DIMENSIONS cx = 19.5 in
cy = 19.5 in
FACTORED AXIAL LOAD Pu = 224.8 k
FACTORED MAGNIFIED MOMENT Mu,x = 96.62 ft-k
Mu,y = 84.82 ft-k
FACTORED SHEAR LOAD Vu,x = 17.98 k
Vu,y = 26.98 k
COLUMN VERT. REINF. 5 # 8 at x dir.
5 # 8 at y dir.
SHEAR REINF. 4 legs,# 3 @ 1.56 in o.c., x dir. THE COLUMN DESIGN IS ADEQUATE.4 legs,# 3 @ 1.56 in o.c., y dir.
ANALYSIS
f Pn (k)
f Pn (kN) f Mn (kN.m)AT AXIAL LOAD ONLY 748 0
AT MAXIMUM LOAD 748 67
AT 0 % TENSION 686 97
AT 25 % TENSION 562 142
AT 50 % TENSION 444 167
ATe t = 0.002 257 188
AT BALANCED CONDITION 245 189
f Mn (ft-k) ATe t = 0.005 0 234
AT FLEXURE ONLY 0 234
CHECK FLEXURAL & AXIAL CAPACITY
Mu = ( Mu,x2
+ Mu,y2
)0.5
= ft-k, (combined bending load.) q = 41.28o
, (the direction of combined load.)
f Pmax =0.80 f [ 0.85 fc' (Ag - Ast) + fy Ast] = 748 kips., (at max axial load, ACI 318-05, Sec. 10.3.6.2)
where f = 0.65 (ACI 318-05, Sec.9.3.2.2) > Pu [Satisfactory]
Ag = 380 in2. Ast = 7.79 in
2.
a = Cbb1 = 12 in (at balanced strain condition, ACI 10.3.2)
f = 0.48 + 83 et = (ACI 318-05, Fig. R9.3.2)
where Cb = d ec / (ec + es) = 15 in et= 0.002069 ec= 0.003
d = 24.757 in, (ACI 7.7.1) b1 = 0.85 ( ACI 318-05, Sec. 10.2.7.3 )
fMn = 0.9 Mn = 234 ft-kips @ Pn = 0, (ACI 318-05, Sec. 9.3.2) ,& et,min = 0.004, (ACI 318-05, Sec. 10.3.5)
fMn = ft-kips @ Pu = 225 kips > Mu [Satisfactory]
rmax = 0.08 (ACI 318-05, Section 10.9) rprovd = 0.020
rmin = 0.01 (ACI 318-05, Section 10.9) [Satisfactory]
CHECK SHEAR CAPACITY (ACI 318-05 Sec. 11.1.1, 11.3.1, & 11.5.6.2)
fVn
= f (Vs
+ Vc) (ACI 318-05 Sec. 11.1.1)
> Vu [Satisfactory]
where f = 0.75 (ACI 318-05 Sec. 9.3.2.3) f y = 40 ksi
d A0 Av Vc = 2 (f c')0.5
A0 Vs = MIN (d fyAv / s , 4Vc) f Vnx 17.21 336 0.49 37.0 148.2 139
y 17.21 336 0.49 37.0 148.2 139
smax = 12.598 (ACI 318-05, Section 7.10.5.2) sprovd = 2 in
smin = 1 (ACI 318-05, Section 7.10.4.3) [Satisfactory]
(Total 16 # 8)
128.569
193
0.652
-100
0
100
200
300
400
500
600
700
800
050
100
150
200
250
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
10/45
R E I N F O R C E M E N T
SIZE DIAM. AREA
# 0 #REF!
3 0.39370 0.12 3 10
4 0.47244 0.18 4 12
5 0.55118 0.24 5 14 Mu,x = 96.6207 ft-k
6 0.62992 0.31 6 16 Mu,y = 84.8197 ft-k
7 0.70866 0.39 7 18
8 0.78740 0.49 8 20
9 0.86614 0.59 9 2210 0.98425 0.76 10 25
11 1.25984 1.25 11 32
14 1.57480 1.95 14 40
STRESS STRAIN COMPUTATION AT MAXIMUM LOAD
1ST ESTIMATE
Axial load fPn / f = 1151 k
Distance to neutral axis c = 28 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 24.757 in
fy
= 61 ksi D = 27.52 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0 qcritial = 45
2 0.91 6.51 0.002 61 53 7 32 dx = 17.213
3 1.83 9.79 0.002 56 98 4 32 dy = 17.213
4 0.97 13.07 0.002 46 42 1 2 sx = 14.925
5 0.12 13.42 0.002 45 5 0 0 sy = 14.925
6 0.12 13.76 0.002 44 5 0 0 Asx = 0.131 in2
/ in
7 0.12 14.10 0.001 42 5 0 0 Asx = 0.131 in2
/ in
8 0.53 14.44 0.001 41 20 -1 -1 cx = 19.5
9 0.93 17.02 0.001 33 29 -3 -8 cy = 19.5
10 0.93 19.60 0.001 25 21 -6 -10 7.791
11 0.93 22.18 0.001 17 13 -8 -9 380
12 0.47 24.76 0.000 9 3 -11 -3
CONC 874 59
S 7.872 1168 95
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.75
2 3.22 6.43 12.97 12.86 31.29443 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.50
3 3.22 9.65 19.46 14.65 52.15738 0.00212 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.26
4 3.22 12.86 25.95 27.52 73.02034 0.00177 2.58825 189 3 39 12.86 25.95 12.86 25.95 11.01
5 0.45 13.31 25.95 11.61069 0.00157 2.58321 30 1 2 13.31 25.95 15.31 25.95 13.76
6 0.45 13.76 25.95 11.61069 0.00152 2.57417 30 0 1 13.76 25.95 17.75 25.95 16.51
7 0.45 14.21 25.95 11.61069 0.00148 2.56058 30 0 -1 14.21 25.95 20.19 25.95 19.26
8 0.45 14.65 25.95 11.61069 0.00143 2.54245 30 -1 -2 14.65 25.95 22.63 25.95 22.02
9 6.43 21.09 12.97 125.1777 0.00105 2.25116 282 -4 -97 21.09 12.97 25.08 25.95 24.77
10 6.43 27.52 0.00 41.72591 0.00035 0.98532 41 -11 -36 27.52 0.00 27.52 25.95 27.52
S 27.52 380 874 59
3RD ITERATION
Axial load fPn / f = 1151 k
Distance to neytral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
9 0.93 17.02 0.001 32 28 -3 -8
case 1 case 2 c
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
11/45
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 7 2 -11 -2
CONC 863 66
S 1151 104
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.71
2 3.22 6.43 12.97 12.86 31.29443 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.41
3 3.22 9.65 19.46 14.65 52.15738 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.124 3.22 12.86 25.95 27.52 73.02034 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.82
5 0.45 13.31 25.95 11.61069 0.00155 2.57929 30 1 2 13.31 25.95 15.23 25.95 13.53
6 0.45 13.76 25.95 11.61069 0.0015 2.56777 30 0 1 13.76 25.95 17.60 25.95 16.24
7 0.45 14.21 25.95 11.61069 0.00145 2.55153 30 0 -1 14.21 25.95 19.96 25.95 18.94
8 0.45 14.65 25.95 11.61069 0.0014 2.5306 29 -1 -2 14.65 25.95 22.33 25.95 21.65
9 6.20 20.86 13.24 121.5209 0.00103 2.22768 271 -4 -90 20.86 13.24 24.69 25.95 24.35
10 6.20 27.06 0.52 42.66986 0.00034 0.9685 41 -10 -35 27.06 0.52 27.06 25.95 27.06
S 27.06 378 863 66
5TH ITERATION
Axial load fPn / f = 1151 k
Distance to neutral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 inE = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
9 0.93 17.02 0.001 32 28 -3 -8
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 7 2 -11 -2
CONC 863 66
S 1151 104
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.71
2 3.22 6.43 12.97 12.86 31.29443 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.41
3 3.22 9.65 19.46 14.65 52.15738 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.12
4 3.22 12.86 25.95 27.52 73.02034 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.82
5 0.45 13.31 25.95 11.61069 0.00155 2.57931 30 1 2 13.31 25.95 15.23 25.95 13.53
6 0.45 13.76 25.95 11.61069 0.0015 2.56778 30 0 1 13.76 25.95 17.60 25.95 16.24
7 0.45 14.21 25.95 11.61069 0.00145 2.55156 30 0 -1 14.21 25.95 19.96 25.95 18.94
8 0.45 14.65 25.95 11.61069 0.0014 2.53063 29 -1 -2 14.65 25.95 22.33 25.95 21.65
9 6.20 20.86 13.23 121.5295 0.00103 2.22774 271 -4 -90 20.86 13.23 24.69 25.95 24.35
10 6.20 27.06 0.52 42.66786 0.00034 0.96854 41 -10 -35 27.06 0.52 27.06 25.95 27.06
S 27.06 378 863 66
7TH ITERATION
Axial load fPn / f = 1151 k
Distance to neutral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
case 1 case 2 ca
case 1 case 2 ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
12/45
9 0.93 17.02 0.001 32 28 -3 -8
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 7 2 -11 -2
CONC 863 66
S 1151 104
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.71
2 3.22 6.43 12.97 12.86 31.29443 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.413 3.22 9.65 19.46 14.65 52.15738 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.12
4 3.22 12.86 25.95 27.52 73.02034 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.82
5 0.45 13.31 25.95 11.61069 0.00155 2.57931 30 1 2 13.31 25.95 15.23 25.95 13.53
6 0.45 13.76 25.95 11.61069 0.0015 2.56778 30 0 1 13.76 25.95 17.60 25.95 16.24
7 0.45 14.21 25.95 11.61069 0.00145 2.55156 30 0 -1 14.21 25.95 19.96 25.95 18.94
8 0.45 14.65 25.95 11.61069 0.0014 2.53063 29 -1 -2 14.65 25.95 22.33 25.95 21.65
9 6.20 20.86 13.23 121.5295 0.00103 2.22774 271 -4 -90 20.86 13.23 24.69 25.95 24.35
10 6.20 27.06 0.52 42.66786 0.00034 0.96854 41 -10 -35 27.06 0.52 27.06 25.95 27.06
S 27.06 378 863 66
STRESS-STRAIN COMPUTATIONS AT POINT OF 0% TENSION
Stress at last row of bars fs = 0 ksi
Distance to neutral axis c = 25 in
Beta factor b = 0.85
Compression block a = 21 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 53 91 4 30
4 0.97 13.07 0.001 41 37 1 2
5 0.12 13.42 0.001 40 4 0 0
6 0.12 13.76 0.001 39 4 0 0
7 0.12 14.10 0.001 37 4 0 0
case 1 case 2 ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
13/45
8 0.53 14.44 0.001 36 18 -1 -1
9 0.93 17.02 0.001 27 23 -3 -6
10 0.93 19.60 0.001 18 15 -6 -7
11 0.93 22.18 0.000 9 6 -8 -4
12 0.47 24.76 0.000 0 0 -11 0
CONC 800 103
S 1056 149
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00281 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.482 3.22 6.43 12.97 12.86 31.29443 0.00242 2.58825 81 9 60 6.43 12.97 6.43 12.97 4.95
3 3.22 9.65 19.46 14.65 52.15738 0.00203 2.58825 135 6 64 9.65 19.46 9.65 19.46 7.43
4 3.22 12.86 25.95 27.52 73.02034 0.00164 2.58816 189 3 39 12.86 25.95 12.86 25.95 9.90
5 0.45 13.31 25.95 11.61069 0.00141 2.53691 29 1 2 13.31 25.95 14.85 25.95 12.38
6 0.45 13.76 25.95 11.61069 0.00136 2.51007 29 0 1 13.76 25.95 16.83 25.95 14.85
7 0.45 14.21 25.95 11.61069 0.00131 2.47762 29 0 -1 14.21 25.95 18.81 25.95 17.33
8 0.45 14.65 25.95 11.61069 0.00125 2.43955 28 -1 -2 14.65 25.95 20.79 25.95 19.81
9 5.05 19.71 14.55 102.2725 0.00092 2.08232 213 -3 -61 19.71 14.55 22.77 25.95 22.28
10 5.05 24.76 3.15 44.68698 0.00031 0.87312 39 -8 -28 24.76 3.15 24.76 25.95 24.76
S 24.76 360 800 103
STRESS-STRAIN COMPUTATIONS AT POINT OF 50% TENSION
Stress at last row of bars fs = 30 ksi
Distance to neutral axis c = 18 inBeta factor b = 0.85
Compression block a = 16 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.002 56 49 7 30
3 1.83 9.79 0.001 41 69 4 23
4 0.97 13.07 0.001 25 22 1 1
5 0.12 13.42 0.001 23 2 0 0
6 0.12 13.76 0.001 22 2 0 0
7 0.12 14.10 0.001 20 2 0 0
8 0.53 14.44 0.001 18 8 -1 0
9 0.93 17.02 0.000 6 3 -3 -1
10 0.93 19.60 0.000 -6 -6 -6 3
11 0.93 22.18 -0.001 -18 -17 -8 12
12 0.47 24.76 -0.001 -30 -14 -11 13
CONC 561 177
S 683 257
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00274 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.83
2 3.22 6.43 12.97 12.86 31.29443 0.00221 2.58825 81 9 60 6.43 12.97 6.43 12.97 3.67
3 3.22 9.65 19.46 14.65 52.15738 0.00168 2.58825 135 6 64 9.65 19.46 9.65 19.46 5.50
4 3.22 12.86 25.95 27.52 73.02034 0.00116 2.36139 172 3 36 12.86 25.95 12.86 25.95 7.34
5 0.45 13.31 25.95 11.61069 0.00086 1.99652 23 1 1 13.31 25.95 13.78 25.95 9.17
6 0.45 13.76 25.95 11.61069 0.00079 1.88131 22 0 0 13.76 25.95 14.69 25.95 11.00
7 0.45 14.21 25.95 11.61069 0.00071 1.75586 20 0 0 14.21 25.95 15.60 25.95 12.84
8 0.45 14.65 25.95 11.61069 0.00064 1.62017 19 -1 -1 14.65 25.95 16.51 25.95 14.67
9 1.84 16.50 18.20 40.661 0.00045 1.22643 50 -2 -8 16.50 18.20 17.43 25.95 16.50
10 1.84 18.34 10.46 26.39561 0.00015 0.45219 12 -4 -4 18.34 10.46 18.34 25.95 18.34
S 18.34 280 561 177
STRESS-STRAIN COMPUTATIONS AT BALANCED CONDITION
Stress at last row of bars fs = 60.9 ksi
Distance to neutral axis c = 15 in
Beta factor b = 0.85
Compression block a = 12 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.002 48 42 7 25
3 1.83 9.79 0.001 29 48 4 16
4 0.97 13.07 0.000 9 7 1 0
5 0.12 13.42 0.000 7 1 0 0
6 0.12 13.76 0.000 5 0 0 0
case 1 case 2 ca
cacase 1 case 2
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
14/45
7 0.12 14.10 0.000 3 0 0 0
8 0.53 14.44 0.000 1 -1 -1 0
9 0.93 17.02 0.000 -14 -13 -3 4
10 0.93 19.60 -0.001 -29 -27 -6 13
11 0.93 22.18 -0.002 -45 -42 -8 29
12 0.47 24.76 -0.002 -60 -28 -11 26
CONC 389 177
S 376 290
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b controlD
ec fc force arm moment to end b to end b to end1 3.22 3.22 6.49 0.00 10.43148 0.00267 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.47
2 3.22 6.43 12.97 12.86 31.29443 0.00201 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.93
3 3.22 9.65 19.46 14.65 52.15738 0.00135 2.50674 131 6 62 9.65 19.46 9.65 19.46 4.40
4 3.22 12.86 25.95 27.52 73.02034 0.0007 1.7248 126 3 26 12.86 25.95 12.86 25.95 5.86
5 0.30 13.16 25.95 7.729089 0.00034 0.94756 7 1 0 13.31 25.95 13.16 25.95 7.33
6 0.30 13.46 25.95 7.729089 0.00027 0.79128 6 0 0 13.76 25.95 13.46 25.95 8.79
7 0.30 13.76 25.95 7.729089 0.00021 0.62788 5 0 0 14.21 25.95 13.76 25.95 10.26
8 0.30 14.06 25.95 7.729089 0.00015 0.45737 4 0 0 14.65 25.95 14.06 25.95 11.72
9 0.30 14.35 25.95 7.729089 9.1E-05 0.27975 2 0 0 14.65 20.30 14.35 25.95 13.19
10 0.30 14.65 25.95 7.729089 3E-05 0.09503 1 -1 0 14.65 14.66 14.65 25.95 14.65
S 14.65 213 389 177
STRESS-STRAIN COMPUTATIONS AT Pu = 0.1 * f'c * Ag < = = Not used
1ST ESTIMATE
Axial load Pn = 116 k
Distance to neutral axis c = 15 in
Beta factor b = 0.85
Compression block a = 12 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.002 48 42 7 25
3 1.83 9.79 0.001 29 48 4 16
4 0.97 13.07 0.000 9 7 1 0
5 0.12 13.42 0.000 7 1 0 0
6 0.12 13.76 0.000 5 0 0 0
7 0.12 14.10 0.000 3 0 0 0
8 0.53 14.44 0.000 1 -1 -1 0
9 0.93 17.02 0.000 -14 -13 -3 4
10 0.93 19.60 -0.001 -29 -27 -6 13
11 0.93 22.18 -0.002 -45 -42 -8 29
12 0.47 24.76 -0.002 -60 -28 -11 26
CONC 389 177
S 376 290
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00267 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.47
2 3.22 6.43 12.97 12.86 31.29443 0.00201 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.93
3 3.22 9.65 19.46 14.65 52.15738 0.00135 2.50674 131 6 62 9.65 19.46 9.65 19.46 4.40
4 3.22 12.86 25.95 27.52 73.02034 0.0007 1.7248 126 3 26 12.86 25.95 12.86 25.95 5.86
5 0.30 13.16 25.95 7.729089 0.00034 0.94756 7 1 0 13.31 25.95 13.16 25.95 7.33
6 0.30 13.46 25.95 7.729089 0.00027 0.79128 6 0 0 13.76 25.95 13.46 25.95 8.79
7 0.30 13.76 25.95 7.729089 0.00021 0.62788 5 0 0 14.21 25.95 13.76 25.95 10.26
8 0.30 14.06 25.95 7.729089 0.00015 0.45737 4 0 0 14.65 25.95 14.06 25.95 11.72
9 0.30 14.35 25.95 7.729089 9.1E-05 0.27975 2 0 0 14.65 20.30 14.35 25.95 13.19
10 0.30 14.65 25.95 7.729089 3E-05 0.09503 1 -1 0 14.65 14.66 14.65 25.95 14.65
S 14.65 213 389 177
3RD ITERATION
Axial load Pu = 116 k
Distance to neytral axis c = 11 in
Beta factor b = 0.85
Compression block a = 10 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
case 1 case 2 ca
case 1 case 2 ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
15/45
2 0.91 6.51 0.001 37 32 7 19
3 1.83 9.79 0.000 12 17 4 6
4 0.97 13.07 0.000 -13 -13 1 -1
5 0.12 13.42 -0.001 -16 -2 0 0
6 0.12 13.76 -0.001 -19 -2 0 0
7 0.12 14.10 -0.001 -21 -3 0 0
8 0.53 14.44 -0.001 -24 -13 -1 1
9 0.93 17.02 -0.002 -44 -41 -3 11
10 0.93 19.60 -0.002 -61 -57 -6 28
11 0.93 22.18 -0.003 -61 -57 -8 4012 0.47 24.76 -0.004 -61 -28 -11 26
CONC 243 147
S 76 277
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 1.13 1.13 2.29 0.00 1.297375 0.00285 2.58825 3 13 4 3.22 6.49 3.22 6.49 1.13
2 1.13 2.27 4.58 12.86 3.892125 0.00255 2.58825 10 12 10 6.43 12.97 6.43 12.97 2.27
3 1.13 3.40 6.86 14.65 6.486875 0.00225 2.58825 17 11 15 9.65 19.46 9.65 19.46 3.40
4 1.13 4.54 9.15 27.52 9.081625 0.00195 2.58825 24 10 19 12.86 25.95 12.86 25.95 4.54
5 1.13 5.67 11.44 12.97375 0.00165 2.58825 34 9 24 13.31 25.95 12.61 25.95 5.67
6 1.13 6.81 13.73 15.5685 0.00135 2.50466 39 8 24 13.76 25.95 12.36 25.95 6.81
7 1.13 7.94 16.01 18.16325 0.00105 2.24908 41 6 22 14.21 25.95 12.10 25.95 7.94
8 1.13 9.07 18.30 20.758 0.00075 1.82149 38 5 17 14.65 25.95 11.85 25.95 9.079 1.13 10.21 20.59 22.05537 0.00045 1.2219 27 4 9 13.00 22.19 11.60 25.95 10.21
10 1.13 11.34 22.88 24.65012 0.00015 0.4503 11 3 3 11.34 18.43 11.34 25.95 11.34
S 11.34 135 243 147
5TH ITERATION
Axial load Pu = 116 k
Distance to neutral axis c = 12 in
Beta factor b = 0.85
Compression block a = 10 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 39 33 7 20
3 1.83 9.79 0.001 15 22 4 7
4 0.97 13.07 0.000 -10 -9 1 -1
5 0.12 13.42 0.000 -12 -1 0 0
6 0.12 13.76 -0.001 -15 -2 0 0
7 0.12 14.10 -0.001 -17 -2 0 0
8 0.53 14.44 -0.001 -20 -10 -1 1
9 0.93 17.02 -0.001 -39 -36 -3 10
10 0.93 19.60 -0.002 -58 -54 -6 26
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 261 153
S 115 283
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 1.18 1.18 2.37 0.00 1.395526 0.00285 2.58825 4 13 4 3.22 6.49 3.22 6.49 1.18
2 1.18 2.35 4.75 12.86 4.186578 0.00255 2.58825 11 12 11 6.43 12.97 6.43 12.97 2.35
3 1.18 3.53 7.12 14.65 6.97763 0.00225 2.58825 18 11 16 9.65 19.46 9.65 19.46 3.53
4 1.18 4.71 9.49 27.52 9.768682 0.00195 2.58825 25 10 20 12.86 25.95 12.86 25.95 4.71
5 1.18 5.88 11.86 13.95526 0.00165 2.58825 36 8 25 13.31 25.95 12.68 25.95 5.88
6 1.18 7.06 14.24 16.74631 0.00135 2.50466 42 7 25 13.76 25.95 12.50 25.95 7.06
7 1.18 8.23 16.61 19.53736 0.00105 2.24908 44 6 22 14.21 25.95 12.31 25.95 8.23
8 1.18 9.41 18.98 22.32842 0.00075 1.82149 41 5 17 14.65 25.95 12.13 25.95 9.41
9 1.18 10.59 21.35 23.72394 0.00045 1.2219 29 4 9 13.21 21.95 11.95 25.95 10.59
10 1.18 11.76 23.73 26.51499 0.00015 0.4503 12 3 3 11.76 17.95 11.76 25.95 11.76
S 11.76 145 261 153
7TH ITERATION
Axial load Pu = 116 k
Distance to neutral axis c = 12 in
Beta factor b = 0.85
Compression block a = 10 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
case 1 case 2
case 1 case 2 ca
ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
16/45
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 39 33 7 20
3 1.83 9.79 0.001 15 22 4 7
4 0.97 13.07 0.000 -10 -9 1 -1
5 0.12 13.42 0.000 -12 -1 0 0
6 0.12 13.76 -0.001 -15 -2 0 0
7 0.12 14.10 -0.001 -17 -2 0 0
8 0.53 14.44 -0.001 -20 -10 -1 1
9 0.93 17.02 -0.001 -39 -36 -3 1010 0.93 19.60 -0.002 -58 -54 -6 26
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 262 153
S 116 283
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 1.18 1.18 2.37 0.00 1.396434 0.00285 2.58825 4 13 4 3.22 6.49 3.22 6.49 1.18
2 1.18 2.35 4.75 12.86 4.189302 0.00255 2.58825 11 12 11 6.43 12.97 6.43 12.97 2.35
3 1.18 3.53 7.12 14.65 6.982171 0.00225 2.58825 18 11 16 9.65 19.46 9.65 19.46 3.53
4 1.18 4.71 9.49 27.52 9.775039 0.00195 2.58825 25 10 20 12.86 25.95 12.86 25.95 4.71
5 1.18 5.88 11.87 13.96434 0.00165 2.58825 36 8 25 13.31 25.95 12.68 25.95 5.88
6 1.18 7.06 14.24 16.75721 0.00135 2.50466 42 7 25 13.76 25.95 12.50 25.95 7.067 1.18 8.24 16.61 19.55008 0.00105 2.24908 44 6 22 14.21 25.95 12.32 25.95 8.24
8 1.18 9.41 18.99 22.34295 0.00075 1.82149 41 5 17 14.65 25.95 12.13 25.95 9.41
9 1.18 10.59 21.36 23.73938 0.00045 1.2219 29 4 9 13.21 21.95 11.95 25.95 10.59
10 1.18 11.77 23.73 26.53225 0.00015 0.4503 12 3 3 11.77 17.94 11.77 25.95 11.77
S 11.77 145 262 153
STRESS STRAIN COMPUTATION AT PURE MOMENT CONDITION
1ST ESTIMATE
Axial load Pu = 0 k
Distance to neutral axis c = 16 in
Beta factor b = 0.85
Compression block a = 14 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.002 52 45 7 27
3 1.83 9.79 0.001 34 57 4 19
4 0.97 13.07 0.001 16 13 1 1
5 0.12 13.42 0.000 14 1 0 0
6 0.12 13.76 0.000 12 1 0 0
7 0.12 14.10 0.000 10 1 0 0
8 0.53 14.44 0.000 9 3 -1 0
9 0.93 17.02 0.000 -5 -5 -3 1
10 0.93 19.60 -0.001 -19 -18 -6 9
11 0.93 22.18 -0.001 -33 -31 -8 22
12 0.47 24.76 -0.002 -47 -22 -11 20
CONC 456 182
S 501 281
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.0027 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.60
2 3.22 6.43 12.97 12.86 31.29443 0.0021 2.58825 81 9 60 6.43 12.97 6.43 12.97 3.20
3 3.22 9.65 19.46 14.65 52.15738 0.00149 2.5663 134 6 64 9.65 19.46 9.65 19.46 4.81
4 3.22 12.86 25.95 27.52 73.02034 0.00089 2.04519 149 3 31 12.86 25.95 12.86 25.95 6.41
5 0.45 13.31 25.95 11.61069 0.00055 1.43848 17 1 1 13.31 25.95 13.39 25.95 8.01
6 0.45 13.76 25.95 11.61069 0.00047 1.25609 15 0 0 13.76 25.95 13.92 25.95 9.61
7 0.45 14.21 25.95 11.61069 0.00038 1.06028 12 0 0 14.21 25.95 14.44 25.95 11.21
8 0.45 14.65 25.95 11.61069 0.0003 0.85105 10 -1 -1 14.65 25.95 14.97 25.95 12.82
9 0.68 15.34 19.52 15.5125 0.00019 0.56775 9 -1 -1 15.34 19.52 15.49 25.95 14.42
10 0.68 16.02 13.10 11.12952 6.4E-05 0.19705 2 -2 0 16.02 13.10 16.02 25.95 16.02
S 16.02 240 456 182
3RD ITERATION
Axial load Pu = 0 k
Distance to neytral axis c = 10 in
Beta factor b = 0.85
Compression block a = 9 in
E = 29000 ksi d = 25 in
case 1 case 2 ca
case 1 case 2 ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
17/45
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 60 0 11 0
2 0.91 6.51 0.001 32 27 7 16
3 1.83 9.79 0.000 5 4 4 1
4 0.97 13.07 -0.001 -23 -22 1 -1
5 0.12 13.42 -0.001 -26 -3 0 0
6 0.12 13.76 -0.001 -29 -3 0 07 0.12 14.10 -0.001 -31 -4 0 0
8 0.53 14.44 -0.001 -34 -18 -1 1
9 0.93 17.02 -0.002 -56 -52 -3 14
10 0.93 19.60 -0.003 -61 -57 -6 28
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.004 -61 -28 -11 26
CONC 203 132
S -11 258
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 1.04 1.04 2.09 0.00 1.082665 0.00285 2.58825 3 13 3 3.22 6.49 3.22 6.49 1.04
2 1.04 2.07 4.18 12.86 3.247996 0.00255 2.58825 8 12 9 6.43 12.97 6.43 12.97 2.07
3 1.04 3.11 6.27 14.65 5.413327 0.00225 2.58825 14 11 13 9.65 19.46 9.65 19.46 3.114 1.04 4.14 8.36 27.52 7.578657 0.00195 2.58825 20 10 17 12.86 25.95 12.86 25.95 4.14
5 1.04 5.18 10.45 10.82665 0.00165 2.58825 28 9 21 13.31 25.95 12.45 25.95 5.18
6 1.04 6.22 12.54 12.99198 0.00135 2.50466 33 8 22 13.76 25.95 12.03 25.95 6.22
7 1.04 7.25 14.63 15.15731 0.00105 2.24908 34 7 20 14.21 25.95 11.61 25.95 7.25
8 1.04 8.29 16.72 17.32265 0.00075 1.82149 32 6 16 14.65 25.95 11.20 25.95 8.29
9 1.04 9.33 18.81 18.40531 0.00045 1.2219 22 5 9 12.51 22.75 10.78 25.95 9.33
10 1.04 10.36 20.90 20.57064 0.00015 0.4503 9 4 3 10.36 19.54 10.36 25.95 10.36
S 10.36 113 203 132
5TH ITERATION
Axial load Pu = 0 k
Distance to neutral axis c = 10 in
Beta factor b = 0.85
Compression block a = 9 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 60 0 11 0
2 0.91 6.51 0.001 33 28 7 17
3 1.83 9.79 0.000 6 6 4 2
4 0.97 13.07 -0.001 -22 -21 1 -1
5 0.12 13.42 -0.001 -24 -3 0 0
6 0.12 13.76 -0.001 -27 -3 0 0
7 0.12 14.10 -0.001 -30 -4 0 0
8 0.53 14.44 -0.001 -33 -17 -1 1
9 0.93 17.02 -0.002 -54 -51 -3 14
10 0.93 19.60 -0.003 -61 -57 -6 28
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.004 -61 -28 -11 26
CONC 208 134
S 0 260
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 1.05 1.05 2.11 0.00 1.107984 0.00285 2.58825 3 13 3 3.22 6.49 3.22 6.49 1.05
2 1.05 2.10 4.23 12.86 3.323951 0.00255 2.58825 9 12 9 6.43 12.97 6.43 12.97 2.10
3 1.05 3.14 6.34 14.65 5.539919 0.00225 2.58825 14 11 13 9.65 19.46 9.65 19.46 3.14
4 1.05 4.19 8.46 27.52 7.755886 0.00195 2.58825 20 10 17 12.86 25.95 12.86 25.95 4.19
5 1.05 5.24 10.57 11.07984 0.00165 2.58825 29 9 22 13.31 25.95 12.47 25.95 5.24
6 1.05 6.29 12.68 13.29581 0.00135 2.50466 33 8 22 13.76 25.95 12.07 25.95 6.29
7 1.05 7.34 14.80 15.51177 0.00105 2.24908 35 7 20 14.21 25.95 11.67 25.95 7.34
8 1.05 8.39 16.91 17.72774 0.00075 1.82149 32 6 16 14.65 25.95 11.28 25.95 8.39
9 1.05 9.43 19.03 18.83572 0.00045 1.2219 23 5 9 12.57 22.68 10.88 25.95 9.43
10 1.05 10.48 21.14 21.05169 0.00015 0.4503 9 4 3 10.48 19.41 10.48 25.95 10.48
S 10.48 115 208 134
7TH ITERATION
Axial load Pu = 0 k
Distance to neutral axis c = 10 in
Beta factor b = 0.85
Compression block a = 9 in
case 1 case 2
case 1 case 2 ca
ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
18/45
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 60 0 11 0
2 0.91 6.51 0.001 33 28 7 17
3 1.83 9.79 0.000 6 6 4 2
4 0.97 13.07 -0.001 -22 -21 1 -1
5 0.12 13.42 -0.001 -24 -3 0 06 0.12 13.76 -0.001 -27 -3 0 0
7 0.12 14.10 -0.001 -30 -4 0 0
8 0.53 14.44 -0.001 -33 -17 -1 1
9 0.93 17.02 -0.002 -54 -51 -3 14
10 0.93 19.60 -0.003 -61 -57 -6 28
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.004 -61 -28 -11 26
CONC 208 134
S 0 260
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control D ec fc force arm moment to end b to end b to end
1 1.05 1.05 2.11 0.00 1.107974 0.00285 2.58825 3 13 3 3.22 6.49 3.22 6.49 1.05
2 1.05 2.10 4.23 12.86 3.323923 0.00255 2.58825 9 12 9 6.43 12.97 6.43 12.97 2.103 1.05 3.14 6.34 14.65 5.539872 0.00225 2.58825 14 11 13 9.65 19.46 9.65 19.46 3.14
4 1.05 4.19 8.46 27.52 7.75582 0.00195 2.58825 20 10 17 12.86 25.95 12.86 25.95 4.19
5 1.05 5.24 10.57 11.07974 0.00165 2.58825 29 9 22 13.31 25.95 12.47 25.95 5.24
6 1.05 6.29 12.68 13.29569 0.00135 2.50466 33 8 22 13.76 25.95 12.07 25.95 6.29
7 1.05 7.34 14.80 15.51164 0.00105 2.24908 35 7 20 14.21 25.95 11.67 25.95 7.34
8 1.05 8.39 16.91 17.72759 0.00075 1.82149 32 6 16 14.65 25.95 11.28 25.95 8.39
9 1.05 9.43 19.03 18.83556 0.00045 1.2219 23 5 9 12.57 22.68 10.88 25.95 9.43
10 1.05 10.48 21.14 21.05151 0.00015 0.4503 9 4 3 10.48 19.41 10.48 25.95 10.48
S 10.48 115 208 134
STRESS STRAIN COMPUTATION AT MAXIMUM LOAD
1ST ESTIMATE
Axial load Pu = 225 kDistance to neutral axis c = 28 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 24.757 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 98 4 32
4 0.97 13.07 0.002 46 42 1 25 0.12 13.42 0.002 45 5 0 0
6 0.12 13.76 0.002 44 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
9 0.93 17.02 0.001 33 29 -3 -8
10 0.93 19.60 0.001 25 21 -6 -10
11 0.93 22.18 0.001 17 13 -8 -9
12 0.47 24.76 0.000 9 3 -11 -3
CONC 874 59
S 1168 95
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b controlDA
ec fc force arm moment to end b to end b to end1 3.22 3.22 6.49 0.00 10.43148 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.75
2 3.22 6.43 12.97 12.86 31.29443 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.50
3 3.22 9.65 19.46 14.65 52.15738 0.00212 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.26
4 3.22 12.86 25.95 27.52 73.02034 0.00177 2.58825 189 3 39 12.86 25.95 12.86 25.95 11.01
5 0.45 13.31 25.95 11.61069 0.00157 2.58321 30 1 2 13.31 25.95 15.31 25.95 13.76
6 0.45 13.76 25.95 11.61069 0.00152 2.57417 30 0 1 13.76 25.95 17.75 25.95 16.51
7 0.45 14.21 25.95 11.61069 0.00148 2.56058 30 0 -1 14.21 25.95 20.19 25.95 19.26
8 0.45 14.65 25.95 11.61069 0.00143 2.54245 30 -1 -2 14.65 25.95 22.63 25.95 22.02
9 6.43 21.09 12.97 125.1777 0.00105 2.25116 282 -4 -97 21.09 12.97 25.08 25.95 24.77
10 6.43 27.52 0.00 41.72591 0.00035 0.98532 41 -11 -36 27.52 0.00 27.52 25.95 27.52
case 1 case 2 ca
case 1 case 2 ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
19/45
S 27.52 380 874 59
3RD ITERATION
Axial load Pu = 225 k
Distance to neytral axis c = 14 in
Beta factor b = 0.85
Compression block a = 12 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc'
= 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.002 47 40 7 24
3 1.83 9.79 0.001 26 44 4 14
4 0.97 13.07 0.000 6 3 1 0
5 0.12 13.42 0.000 4 0 0 0
6 0.12 13.76 0.000 2 0 0 0
7 0.12 14.10 0.000 0 0 0 0
8 0.53 14.44 0.000 -2 -1 -1 0
9 0.93 17.02 -0.001 -18 -17 -3 5
10 0.93 19.60 -0.001 -34 -32 -6 16
11 0.93 22.18 -0.002 -50 -47 -8 33
12 0.47 24.76 -0.002 -61 -28 -11 26
CONC 361 173
S 322 291
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00266 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.41
2 3.22 6.43 12.97 12.86 31.29443 0.00197 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.81
3 3.22 9.65 19.46 14.65 52.15738 0.00128 2.46328 128 6 61 9.65 19.46 9.65 19.46 4.22
4 3.22 12.86 25.95 27.52 73.02034 0.0006 1.53878 112 3 23 12.86 25.95 12.86 25.95 5.62
5 0.20 13.06 25.95 5.159803 0.00023 0.68207 4 1 0 13.31 25.95 13.06 25.95 7.03
6 0.20 13.26 25.95 5.159803 0.00019 0.5658 3 1 0 13.76 25.95 13.26 25.95 8.43
7 0.20 13.46 25.95 5.159803 0.00015 0.44609 2 0 0 14.21 25.95 13.46 25.95 9.84
8 0.20 13.66 25.95 5.159803 0.00011 0.32294 2 0 0 14.65 25.95 13.66 25.95 11.25
9 0.20 13.86 25.95 5.159803 6.4E-05 0.19634 1 0 0 14.36 20.64 13.86 25.95 12.65
10 0.20 14.06 25.95 5.159803 2.1E-05 0.06631 0 0 0 14.06 15.33 14.06 25.95 14.06
S 14.06 198 361 173
5TH ITERATION
Axial load Pu = 225 k
Distance to neutral axis c = 13 in
Beta factor b = 0.85
Compression block a = 11 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 43 37 7 22
3 1.83 9.79 0.001 21 34 4 11
4 0.97 13.07 0.000 -1 -1 1 0
5 0.12 13.42 0.000 -3 0 0 0
6 0.12 13.76 0.000 -6 -1 0 0
7 0.12 14.10 0.000 -8 -1 0 0
8 0.53 14.44 0.000 -10 -5 -1 0
9 0.93 17.02 -0.001 -28 -26 -3 7
10 0.93 19.60 -0.002 -45 -42 -6 2011 0.93 22.18 -0.002 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 309 162
S 218 290
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00263 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.29
2 3.22 6.43 12.97 12.86 31.29443 0.00188 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.59
3 3.22 9.65 19.46 14.65 52.15738 0.00113 2.33813 122 6 58 9.65 19.46 9.65 19.46 3.88
case 1 case 2
case 1 case 2 ca
ca
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
20/45
4 3.22 12.86 25.95 27.52 73.02034 0.00039 1.07609 79 3 16 12.86 25.95 12.86 25.95 5.17
5 0.01 12.88 25.95 0.272919 1.3E-05 0.04205 0 1 0 13.31 25.95 12.88 25.95 6.46
6 0.01 12.89 25.95 0.272919 1.1E-05 0.03443 0 1 0 13.76 25.95 12.89 25.95 7.76
7 0.01 12.90 25.95 0.272919 8.5E-06 0.0268 0 1 0 14.21 25.95 12.90 25.95 9.05
8 0.01 12.91 25.95 0.272919 6.1E-06 0.01916 0 1 0 14.65 25.95 12.91 25.95 10.34
9 0.01 12.92 25.95 0.272919 3.7E-06 0.0115 0 1 0 13.79 21.28 12.92 25.95 11.63
10 0.01 12.93 25.95 0.272919 1.2E-06 0.00384 0 1 0 12.93 16.62 12.93 25.95 12.93
S 12.93 169 309 162
7TH ITERATION
Axial load Pu = 225 k
Distance to neutral axis c = 13 in
Beta factor b = 0.85
Compression block a = 11 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 43 37 7 23
3 1.83 9.79 0.001 22 35 4 11
4 0.97 13.07 0.000 0 0 1 0
5 0.12 13.42 0.000 -3 0 0 0
6 0.12 13.76 0.000 -5 -1 0 0
7 0.12 14.10 0.000 -7 -1 0 0
8 0.53 14.44 0.000 -10 -5 -1 0
9 0.93 17.02 -0.001 -27 -25 -3 7
10 0.93 19.60 -0.002 -44 -41 -6 20
11 0.93 22.18 -0.002 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 312 163
S 225 290
Ec = 3145 ksi eo = 0.0016
conc sec thick to end b control DA ec fc force arm moment to end b to end b to end
1 3.22 3.22 6.49 0.00 10.43148 0.00263 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.30
2 3.22 6.43 12.97 12.86 31.29443 0.00189 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.60
3 3.22 9.65 19.46 14.65 52.15738 0.00115 2.34982 123 6 58 9.65 19.46 9.65 19.46 3.90
4 3.22 12.86 25.95 27.52 73.02034 0.0004 1.11654 82 3 17 12.86 25.95 12.86 25.95 5.20
5 0.02 12.89 25.95 0.637828 3.1E-05 0.09711 0 1 0 13.31 25.95 12.89 25.95 6.51
6 0.02 12.91 25.95 0.637828 2.6E-05 0.07959 0 1 0 13.76 25.95 12.91 25.95 7.81
7 0.02 12.94 25.95 0.637828 2E-05 0.06201 0 1 0 14.21 25.95 12.94 25.95 9.11
8 0.02 12.96 25.95 0.637828 1.4E-05 0.04437 0 1 0 14.65 25.95 12.96 25.95 10.41
9 0.02 12.99 25.95 0.637828 8.5E-06 0.02667 0 1 0 13.83 21.24 12.99 25.95 11.71
10 0.02 13.01 25.95 0.637828 2.8E-06 0.00891 0 1 0 13.01 16.53 13.01 25.95 13.01
S 13.01 171 312 163
f Pn (kips) f Mn (ft-kips)0 234 0
0 234 245
245 189 257
257 188 444
444 167 562
562 142 686
686 97 748
748 67 748
748 0
f Pn (kips) f Mn (ft-kips)0 234
225 193
case 1 case 2 c
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
21/45
245 189
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
22/45
2ND ESTIMATE
Axial load fPn / f = 1151 k
Distance to neutral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 25 in
fy
= 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
9 0.93 17.02 0.001 32 28 -3 -8
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 8 2 -11 -2
CONC 864 65
S 1153 103
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
5.55 1 3.22 3.22 6.49 0.00 10.4315 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.7
11.10 2 3.22 6.43 12.97 12.86 31.2944 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.4
16.65 3 3.22 9.65 19.46 14.65 52.1574 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.1
22.20 4 3.22 12.86 25.95 27.52 73.0203 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.8
27.75 5 0.45 13.31 25.95 11.6107 0.00155 2.57985 30 1 2 13.31 25.95 15.24 25.95 13.5
33.30 6 0.45 13.76 25.95 11.6107 0.0015 2.56863 30 0 1 13.76 25.95 17.62 25.95 16.2
38.85 7 0.45 14.21 25.95 11.6107 0.00145 2.55274 30 0 -1 14.21 25.95 19.99 25.95 18.944.40 8 0.45 14.65 25.95 11.6107 0.0014 2.53216 29 -1 -2 14.65 25.95 22.37 25.95 21.6
49.96 9 6.23 20.89 13.20 121.976 0.00103 2.23067 272 -4 -91 20.89 13.20 24.74 25.95 24.4
55.51 10 6.23 27.12 0.46 42.563 0.00034 0.97062 41 -10 -35 27.12 0.46 27.12 25.95 27.1
S 27.12 378 864 65
4TH ITERATION
Axial load fPn / f = 1151 k
Distance to neutral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm momentto end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
9 0.93 17.02 0.001 32 28 -3 -8
case 2 e 3 case 1
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
23/45
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 7 2 -11 -2
CONC 863 66
S 1151 104
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control DA ec fc force arm moment to end b to end b to en
5.46 1 3.22 3.22 6.49 0.00 10.4315 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.7
10.92 2 3.22 6.43 12.97 12.86 31.2944 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.4
16.37 3 3.22 9.65 19.46 14.65 52.1574 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.121.83 4 3.22 12.86 25.95 27.52 73.0203 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.8
27.29 5 0.45 13.31 25.95 11.6107 0.00155 2.57931 30 1 2 13.31 25.95 15.23 25.95 13.5
32.75 6 0.45 13.76 25.95 11.6107 0.0015 2.56778 30 0 1 13.76 25.95 17.60 25.95 16.2
38.21 7 0.45 14.21 25.95 11.6107 0.00145 2.55156 30 0 -1 14.21 25.95 19.96 25.95 18.9
43.66 8 0.45 14.65 25.95 11.6107 0.0014 2.53063 29 -1 -2 14.65 25.95 22.33 25.95 21.6
49.12 9 6.20 20.86 13.23 121.53 0.00103 2.22774 271 -4 -90 20.86 13.23 24.69 25.95 24.3
54.58 10 6.20 27.06 0.52 42.6679 0.00034 0.96854 41 -10 -35 27.06 0.52 27.06 25.95 27.0
S 27.06 378 863 66
6TH ITERATION
Axial load fPn / f = 1151 k
Distance to neutral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 inE = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
9 0.93 17.02 0.001 32 28 -3 -8
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 7 2 -11 -2
CONC 863 66
S 1151 104
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
5.46 1 3.22 3.22 6.49 0.00 10.4315 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.7
10.92 2 3.22 6.43 12.97 12.86 31.2944 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.4
16.37 3 3.22 9.65 19.46 14.65 52.1574 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.1
21.83 4 3.22 12.86 25.95 27.52 73.0203 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.8
27.29 5 0.45 13.31 25.95 11.6107 0.00155 2.57931 30 1 2 13.31 25.95 15.23 25.95 13.5
32.75 6 0.45 13.76 25.95 11.6107 0.0015 2.56778 30 0 1 13.76 25.95 17.60 25.95 16.2
38.21 7 0.45 14.21 25.95 11.6107 0.00145 2.55156 30 0 -1 14.21 25.95 19.96 25.95 18.9
43.67 8 0.45 14.65 25.95 11.6107 0.0014 2.53063 29 -1 -2 14.65 25.95 22.33 25.95 21.6
49.12 9 6.20 20.86 13.23 121.53 0.00103 2.22774 271 -4 -90 20.86 13.23 24.69 25.95 24.3
54.58 10 6.20 27.06 0.52 42.6679 0.00034 0.96854 41 -10 -35 27.06 0.52 27.06 25.95 27.0
S 27.06 378 863 66
8TH ITERATION
Axial load fPn / f = 1151 k
Distance to neutral axis c = 27 in
Beta factor b = 0.85
Compression block a = 23 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 61 53 7 32
3 1.83 9.79 0.002 56 97 4 32
4 0.97 13.07 0.002 45 41 1 2
5 0.12 13.42 0.002 44 5 0 0
6 0.12 13.76 0.001 43 5 0 0
7 0.12 14.10 0.001 42 5 0 0
8 0.53 14.44 0.001 41 20 -1 -1
case 2 e 3 case 1
case 2 e 3 case 1
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
24/45
9 0.93 17.02 0.001 32 28 -3 -8
10 0.93 19.60 0.001 24 20 -6 -10
11 0.93 22.18 0.001 16 12 -8 -9
12 0.47 24.76 0.000 7 2 -11 -2
CONC 863 66
S 1151 104
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control DA ec fc force arm moment to end b to end b to en
5.46 1 3.22 3.22 6.49 0.00 10.4315 0.00282 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.7
10.92 2 3.22 6.43 12.97 12.86 31.2944 0.00247 2.58825 81 9 60 6.43 12.97 6.43 12.97 5.416.37 3 3.22 9.65 19.46 14.65 52.1574 0.00211 2.58825 135 6 64 9.65 19.46 9.65 19.46 8.1
21.83 4 3.22 12.86 25.95 27.52 73.0203 0.00175 2.58825 189 3 39 12.86 25.95 12.86 25.95 10.8
27.29 5 0.45 13.31 25.95 11.6107 0.00155 2.57931 30 1 2 13.31 25.95 15.23 25.95 13.5
32.75 6 0.45 13.76 25.95 11.6107 0.0015 2.56778 30 0 1 13.76 25.95 17.60 25.95 16.2
38.21 7 0.45 14.21 25.95 11.6107 0.00145 2.55156 30 0 -1 14.21 25.95 19.96 25.95 18.9
43.67 8 0.45 14.65 25.95 11.6107 0.0014 2.53063 29 -1 -2 14.65 25.95 22.33 25.95 21.6
49.12 9 6.20 20.86 13.23 121.53 0.00103 2.22774 271 -4 -90 20.86 13.23 24.69 25.95 24.3
54.58 10 6.20 27.06 0.52 42.6679 0.00034 0.96854 41 -10 -35 27.06 0.52 27.06 25.95 27.0
S 27.06 378 863 66
STRESS-STRAIN COMPUTATIONS AT POINT OF 25% TENSION
Stress at last row of bars fs = 15 ksi
Distance to neutral axis c = 21 in
Beta factor b = 0.85
Compression block a = 18 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.003 61 0 11 0
2 0.91 6.51 0.002 60 53 7 32
3 1.83 9.79 0.002 47 80 4 27
4 0.97 13.07 0.001 33 30 1 2
5 0.12 13.42 0.001 32 3 0 0
6 0.12 13.76 0.001 30 3 0 0
7 0.12 14.10 0.001 29 3 0 0
case 2 e 3 case 1
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
25/45
8 0.53 14.44 0.001 27 13 -1 -1
9 0.93 17.02 0.001 17 13 -3 -4
10 0.93 19.60 0.000 6 3 -6 -2
11 0.93 22.18 0.000 -5 -4 -8 3
12 0.47 24.76 -0.001 -15 -7 -11 7
CONC 674 154
S 864 218
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
4.99 1 3.22 3.22 6.49 0.00 10.4315 0.00277 2.58825 27 12 27 3.22 6.49 3.22 6.49 2.19.99 2 3.22 6.43 12.97 12.86 31.2944 0.00231 2.58825 81 9 60 6.43 12.97 6.43 12.97 4.2
14.98 3 3.22 9.65 19.46 14.65 52.1574 0.00186 2.58825 135 6 64 9.65 19.46 9.65 19.46 6.3
19.97 4 3.22 12.86 25.95 27.52 73.0203 0.0014 2.52922 185 3 39 12.86 25.95 12.86 25.95 8.4
24.97 5 0.45 13.31 25.95 11.6107 0.00114 2.34033 27 1 2 13.31 25.95 14.23 25.95 10.5
29.96 6 0.45 13.76 25.95 11.6107 0.00107 2.27443 26 0 0 13.76 25.95 15.60 25.95 12.6
34.95 7 0.45 14.21 25.95 11.6107 0.00101 2.20077 26 0 0 14.21 25.95 16.97 25.95 14.7
39.95 8 0.45 14.65 25.95 11.6107 0.00095 2.11935 25 -1 -1 14.65 25.95 18.33 25.95 16.8
44.94 9 3.21 17.86 16.65 68.3126 0.00069 1.70629 117 -2 -24 17.86 16.65 19.70 25.95 18.9
49.93 10 3.21 21.07 7.35 38.481 0.00023 0.66842 26 -6 -12 21.07 7.35 21.07 25.95 21.0
S 21.07 320 674 154
STRESS-STRAIN COMPUTATIONS AT POINT OF et = 0.002
Stress at last row of bars fs = 58 ksi
Distance to neutral axis c = 15 inBeta factor b = 0.85
Compression block a = 13 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.002 49 42 7 26
3 1.83 9.79 0.001 30 49 4 16
4 0.97 13.07 0.000 10 8 1 0
5 0.12 13.42 0.000 8 1 0 0
6 0.12 13.76 0.000 6 0 0 0
7 0.12 14.10 0.000 4 0 0 0
8 0.53 14.44 0.000 2 0 -1 0
9 0.93 17.02 0.000 -13 -12 -3 3
10 0.93 19.60 -0.001 -28 -26 -6 13
11 0.93 22.18 -0.001 -43 -40 -8 28
12 0.47 24.76 -0.002 -58 -27 -11 25
CONC 399 178
S 395 289
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
3.70 1 3.22 3.22 6.49 0.00 10.4315 0.00268 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.4
7.40 2 3.22 6.43 12.97 12.86 31.2944 0.00203 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.9
11.10 3 3.22 9.65 19.46 14.65 52.1574 0.00138 2.51877 131 6 63 9.65 19.46 9.65 19.46 4.4
14.80 4 3.22 12.86 25.95 27.52 73.0203 0.00073 1.78086 130 3 27 12.86 25.95 12.86 25.95 5.9
18.49 5 0.45 13.31 25.95 11.6107 0.00036 1.00014 12 1 1 13.31 25.95 13.20 25.95 7.4
22.19 6 0.45 13.76 25.95 11.6107 0.00027 0.76967 9 0 0 13.76 25.95 13.53 25.95 8.9
25.89 7 0.45 14.21 25.95 11.6107 0.00018 0.5236 6 0 0 14.21 25.95 13.86 25.95 10.4
29.59 8 0.45 14.65 25.95 11.6107 8.5E-05 0.26192 3 -1 0 14.65 25.95 14.19 25.95 11.8
33.29 9 0.10 14.75 20.19 2.30176 3E-05 0.09421 0 -1 0 14.75 20.19 14.52 25.95 13.3
36.99 10 0.10 14.85 14.43 1.72697 1E-05 0.0316 0 -1 0 14.85 14.43 14.85 25.95 14.8
S 14.85 217 399 178
STRESS-STRAIN COMPUTATIONS AT POINT OF et = 0.005
Stress at last row of bars fs = 145 ksi
Distance to neutral axis c = 9 in
Beta factor b = 0.85
Compression block a = 8 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 57 0 11 0
2 0.91 6.51 0.001 26 21 7 13
3 1.83 9.79 0.000 -5 -9 4 -3
4 0.97 13.07 -0.001 -36 -35 1 -2
5 0.12 13.42 -0.001 -39 -5 0 0
6 0.12 13.76 -0.001 -42 -5 0 0
e 3 case 1
e 3 case 1
case 2
case 2
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
26/45
7 0.12 14.10 -0.002 -45 -5 0 0
8 0.53 14.44 -0.002 -48 -25 -1 1
9 0.93 17.02 -0.003 -61 -57 -3 15
10 0.93 19.60 -0.003 -61 -57 -6 28
11 0.93 22.18 -0.004 -61 -57 -8 40
12 0.47 24.76 -0.005 -61 -28 -11 26
CONC 163 115
S -99 233
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b controlD
ec fc force arm moment to end b to end b to en2.96 1 0.93 0.93 1.87 0.00 0.8692 0.00285 2.58825 2 13 2 3.22 6.49 3.22 6.49 0.9
5.91 2 0.93 1.86 3.75 12.86 2.60761 0.00255 2.58825 7 12 7 6.43 12.97 6.43 12.97 1.8
8.87 3 0.93 2.79 5.62 14.65 4.34602 0.00225 2.58825 11 11 11 9.65 19.46 9.65 19.46 2.7
11.82 4 0.93 3.71 7.49 27.52 6.08442 0.00195 2.58825 16 11 14 12.86 25.95 12.86 25.95 3.7
14.78 5 0.93 4.64 9.36 8.69203 0.00165 2.58825 22 10 18 13.31 25.95 12.27 25.95 4.6
17.73 6 0.93 5.57 11.24 10.4304 0.00135 2.50466 26 9 19 13.76 25.95 11.67 25.95 5.5
20.69 7 0.93 6.50 13.11 12.1688 0.00105 2.24908 27 8 18 14.21 25.95 11.07 25.95 6.5
23.64 8 0.93 7.43 14.98 13.9073 0.00075 1.82149 25 7 14 14.65 25.95 10.48 25.95 7.4
26.60 9 0.93 8.36 16.85 14.7765 0.00045 1.2219 18 6 9 11.97 23.36 9.88 25.95 8.3
29.55 10 0.93 9.28 18.73 16.5149 0.00015 0.4503 7 5 3 9.28 20.77 9.28 25.95 9.2
S 9.28 90 163 115
2ND ESTIMATE
Axial load Pn = 116 k
Distance to neutral axis c = 5 in
Beta factor b = 0.85
Compression block a = 4 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.001 25 0 11 0
2 0.91 6.51 -0.001 -38 -35 7 -21
3 1.83 9.79 -0.004 -61 -111 4 -37
4 0.97 13.07 -0.006 -61 -59 1 -3
5 0.12 13.42 -0.006 -61 -7 0 0
6 0.12 13.76 -0.006 -61 -7 0 0
7 0.12 14.10 -0.006 -61 -7 0 0
8 0.53 14.44 -0.007 -61 -32 -1 2
9 0.93 17.02 -0.008 -61 -57 -3 15
10 0.93 19.60 -0.010 -61 -57 -6 28
11 0.93 22.18 -0.012 -61 -57 -8 40
12 0.47 24.76 -0.013 -61 -28 -11 26
CONC 39 36
S -420 85
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
2.96 1 0.45 0.45 0.91 0.00 0.20562 0.00285 2.58825 1 14 1 3.22 6.49 3.22 6.49 0.4
5.91 2 0.45 0.90 1.82 12.86 0.61686 0.00255 2.58825 2 13 2 6.43 12.97 6.43 12.97 0.9
8.87 3 0.45 1.35 2.73 14.65 1.02811 0.00225 2.58825 3 13 3 9.65 19.46 9.65 19.46 1.3
11.82 4 0.45 1.81 3.64 27.52 1.43935 0.00195 2.58825 4 12 4 12.86 25.95 12.86 25.95 1.8
14.78 5 0.45 2.26 4.55 2.05621 0.00165 2.58825 5 12 5 13.31 25.95 11.47 25.95 2.2
17.73 6 0.45 2.71 5.46 2.46746 0.00135 2.50466 6 11 6 13.76 25.95 10.08 25.95 2.7
20.69 7 0.45 3.16 6.38 2.8787 0.00105 2.24908 6 11 6 14.21 25.95 8.69 25.95 3.1
23.64 8 0.45 3.61 7.29 3.28994 0.00075 1.82149 6 10 5 14.65 25.95 7.30 25.95 3.6
26.60 9 0.45 4.06 8.20 3.49556 0.00045 1.2219 4 10 4 9.58 26.08 5.91 25.95 4.0
29.55 10 0.45 4.52 9.11 3.90681 0.00015 0.4503 2 9 1 4.52 26.20 4.52 25.95 4.5
S 4.52 21 39 36
4TH ITERATION
Axial load Pu = 116 k
Distance to neutral axis c = 12 in
Beta factor b = 0.85
Compression block a = 10 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
case 2
case 2
e 3 case 1
e 3 case 1
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
27/45
2 0.91 6.51 0.001 39 34 7 20
3 1.83 9.79 0.001 15 23 4 8
4 0.97 13.07 0.000 -9 -8 1 0
5 0.12 13.42 0.000 -11 -1 0 0
6 0.12 13.76 0.000 -14 -2 0 0
7 0.12 14.10 -0.001 -16 -2 0 0
8 0.53 14.44 -0.001 -19 -10 -1 1
9 0.93 17.02 -0.001 -38 -35 -3 10
10 0.93 19.60 -0.002 -57 -53 -6 26
11 0.93 22.18 -0.003 -61 -57 -8 4012 0.47 24.76 -0.003 -61 -28 -11 26
CONC 267 155
S 127 284
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
2.29 1 1.19 1.19 2.40 0.00 1.42407 0.00285 2.58825 4 13 4 3.22 6.49 3.22 6.49 1.1
4.58 2 1.19 2.38 4.79 12.86 4.2722 0.00255 2.58825 11 12 11 6.43 12.97 6.43 12.97 2.3
6.86 3 1.19 3.56 7.19 14.65 7.12033 0.00225 2.58825 18 11 17 9.65 19.46 9.65 19.46 3.5
9.15 4 1.19 4.75 9.59 27.52 9.96846 0.00195 2.58825 26 10 21 12.86 25.95 12.86 25.95 4.7
11.44 5 1.19 5.94 11.98 14.2407 0.00165 2.58825 37 8 26 13.31 25.95 12.70 25.95 5.9
13.73 6 1.19 7.13 14.38 17.0888 0.00135 2.50466 43 7 26 13.76 25.95 12.54 25.95 7.1
16.01 7 1.19 8.32 16.78 19.9369 0.00105 2.24908 45 6 23 14.21 25.95 12.37 25.95 8.3
18.30 8 1.19 9.51 19.17 22.785 0.00075 1.82149 42 5 17 14.65 25.95 12.21 25.95 9.520.59 9 1.19 10.69 21.57 24.2091 0.00045 1.2219 30 4 9 13.27 21.88 12.05 25.95 10.6
22.88 10 1.19 11.88 23.97 27.0572 0.00015 0.4503 12 2 3 11.88 17.81 11.88 25.95 11.8
S 11.88 148 267 155
6TH ITERATION
Axial load Pu = 116 k
Distance to neutral axis c = 12 in
Beta factor b = 0.85
Compression block a = 10 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 39 33 7 20
3 1.83 9.79 0.001 15 22 4 7
4 0.97 13.07 0.000 -10 -9 1 -1
5 0.12 13.42 0.000 -12 -1 0 0
6 0.12 13.76 -0.001 -15 -2 0 0
7 0.12 14.10 -0.001 -17 -2 0 0
8 0.53 14.44 -0.001 -20 -10 -1 1
9 0.93 17.02 -0.001 -39 -36 -3 10
10 0.93 19.60 -0.002 -58 -54 -6 26
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 262 153
S 116 283
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
2.37 1 1.18 1.18 2.37 0.00 1.39644 0.00285 2.58825 4 13 4 3.22 6.49 3.22 6.49 1.1
4.75 2 1.18 2.35 4.75 12.86 4.18931 0.00255 2.58825 11 12 11 6.43 12.97 6.43 12.97 2.3
7.12 3 1.18 3.53 7.12 14.65 6.98218 0.00225 2.58825 18 11 16 9.65 19.46 9.65 19.46 3.5
9.49 4 1.18 4.71 9.49 27.52 9.77506 0.00195 2.58825 25 10 20 12.86 25.95 12.86 25.95 4.7
11.86 5 1.18 5.88 11.87 13.9644 0.00165 2.58825 36 8 25 13.31 25.95 12.68 25.95 5.8
14.24 6 1.18 7.06 14.24 16.7572 0.00135 2.50466 42 7 25 13.76 25.95 12.50 25.95 7.0
16.61 7 1.18 8.24 16.61 19.5501 0.00105 2.24908 44 6 22 14.21 25.95 12.32 25.95 8.2
18.98 8 1.18 9.41 18.99 22.343 0.00075 1.82149 41 5 17 14.65 25.95 12.13 25.95 9.4
21.35 9 1.18 10.59 21.36 23.7394 0.00045 1.2219 29 4 9 13.21 21.95 11.95 25.95 10.5
23.73 10 1.18 11.77 23.73 26.5323 0.00015 0.4503 12 3 3 11.77 17.94 11.77 25.95 11.7
S 11.77 145 262 153
8TH ITERATION
Axial load Pu = 116 k
Distance to neutral axis c = 12 in
Beta factor b = 0.85
Compression block a = 10 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
e 3 case 1
e 3 case 1
case 2
case 2
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
28/45
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 39 33 7 20
3 1.83 9.79 0.001 15 22 4 7
4 0.97 13.07 0.000 -10 -9 1 -1
5 0.12 13.42 0.000 -12 -1 0 0
6 0.12 13.76 -0.001 -15 -2 0 0
7 0.12 14.10 -0.001 -17 -2 0 0
8 0.53 14.44 -0.001 -20 -10 -1 1
9 0.93 17.02 -0.001 -39 -36 -3 1010 0.93 19.60 -0.002 -58 -54 -6 26
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 262 153
S 116 283
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control DA ec fc force arm moment to end b to end b to en
2.37 1 1.18 1.18 2.37 0.00 1.39643 0.00285 2.58825 4 13 4 3.22 6.49 3.22 6.49 1.1
4.75 2 1.18 2.35 4.75 12.86 4.1893 0.00255 2.58825 11 12 11 6.43 12.97 6.43 12.97 2.3
7.12 3 1.18 3.53 7.12 14.65 6.98217 0.00225 2.58825 18 11 16 9.65 19.46 9.65 19.46 3.5
9.49 4 1.18 4.71 9.49 27.52 9.77504 0.00195 2.58825 25 10 20 12.86 25.95 12.86 25.95 4.7
11.87 5 1.18 5.88 11.87 13.9643 0.00165 2.58825 36 8 25 13.31 25.95 12.68 25.95 5.8
14.24 6 1.18 7.06 14.24 16.7572 0.00135 2.50466 42 7 25 13.76 25.95 12.50 25.95 7.016.61 7 1.18 8.24 16.61 19.5501 0.00105 2.24908 44 6 22 14.21 25.95 12.32 25.95 8.24
18.99 8 1.18 9.41 18.99 22.3429 0.00075 1.82149 41 5 17 14.65 25.95 12.13 25.95 9.4
21.36 9 1.18 10.59 21.36 23.7394 0.00045 1.2219 29 4 9 13.21 21.95 11.95 25.95 10.5
23.73 10 1.18 11.77 23.73 26.5322 0.00015 0.4503 12 3 3 11.77 17.94 11.77 25.95 11.7
S 11.77 145 262 153
2ND ESTIMATE
Axial load Pu = 0 k
Distance to neutral axis c = 8 in
Beta factor b = 0.85
Compression block a = 7 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 52 0 11 0
2 0.91 6.51 0.001 16 13 7 8
3 1.83 9.79 -0.001 -19 -35 4 -12
4 0.97 13.07 -0.002 -55 -54 1 -3
5 0.12 13.42 -0.002 -59 -7 0 0
6 0.12 13.76 -0.002 -61 -7 0 0
7 0.12 14.10 -0.002 -61 -7 0 0
8 0.53 14.44 -0.002 -61 -32 -1 2
9 0.93 17.02 -0.003 -61 -57 -3 15
10 0.93 19.60 -0.004 -61 -57 -6 28
11 0.93 22.18 -0.005 -61 -57 -8 40
12 0.47 24.76 -0.006 -61 -28 -11 26
CONC 121 93
S -208 197
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
3.23 1 0.80 0.80 1.62 0.00 0.64697 0.00285 2.58825 2 13 2 3.22 6.49 3.22 6.49 0.8
6.46 2 0.80 1.60 3.23 12.86 1.94092 0.00255 2.58825 5 13 5 6.43 12.97 6.43 12.97 1.6
9.69 3 0.80 2.40 4.85 14.65 3.23487 0.00225 2.58825 8 12 8 9.65 19.46 9.65 19.46 2.4
12.92 4 0.80 3.20 6.46 27.52 4.52881 0.00195 2.58825 12 11 11 12.86 25.95 12.86 25.95 3.2
16.16 5 0.80 4.00 8.08 6.46973 0.00165 2.58825 17 10 14 13.31 25.95 12.06 25.95 4.0
19.39 6 0.80 4.81 9.69 7.76368 0.00135 2.50466 19 9 15 13.76 25.95 11.25 25.95 4.8
22.62 7 0.80 5.61 11.31 9.05763 0.00105 2.24908 20 9 15 14.21 25.95 10.44 25.95 5.6
25.85 8 0.80 6.41 12.92 10.3516 0.00075 1.82149 19 8 12 14.65 25.95 9.63 25.95 6.4
29.08 9 0.80 7.21 14.54 10.9985 0.00045 1.2219 13 7 8 11.33 24.09 8.82 25.95 7.2
32.31 10 0.80 8.01 16.16 12.2925 0.00015 0.4503 6 6 3 8.01 22.22 8.01 25.95 8.0
S 8.01 67 121 93
4TH ITERATION
Axial load Pu = 0 k
Distance to neutral axis c = 10 in
Beta factor b = 0.85
Compression block a = 9 in
E = 29000 ksi d = 25 in
case 2
case 2
e 3 case 1
e 3 case 1
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
29/45
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
30/45
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 60 0 11 0
2 0.91 6.51 0.001 33 28 7 17
3 1.83 9.79 0.000 6 6 4 2
4 0.97 13.07 -0.001 -22 -21 1 -1
5 0.12 13.42 -0.001 -24 -3 0 06 0.12 13.76 -0.001 -27 -3 0 0
7 0.12 14.10 -0.001 -30 -4 0 0
8 0.53 14.44 -0.001 -33 -17 -1 1
9 0.93 17.02 -0.002 -54 -51 -3 14
10 0.93 19.60 -0.003 -61 -57 -6 28
11 0.93 22.18 -0.003 -61 -57 -8 40
12 0.47 24.76 -0.004 -61 -28 -11 26
CONC 208 134
S 0 260
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control D ec fc force arm moment to end b to end b to en
2.11 1 1.05 1.05 2.11 0.00 1.10797 0.00285 2.58825 3 13 3 3.22 6.49 3.22 6.49 1.0
4.23 2 1.05 2.10 4.23 12.86 3.32392 0.00255 2.58825 9 12 9 6.43 12.97 6.43 12.97 2.16.34 3 1.05 3.14 6.34 14.65 5.53987 0.00225 2.58825 14 11 13 9.65 19.46 9.65 19.46 3.1
8.46 4 1.05 4.19 8.46 27.52 7.75582 0.00195 2.58825 20 10 17 12.86 25.95 12.86 25.95 4.1
10.57 5 1.05 5.24 10.57 11.0797 0.00165 2.58825 29 9 22 13.31 25.95 12.47 25.95 5.2
12.68 6 1.05 6.29 12.68 13.2957 0.00135 2.50466 33 8 22 13.76 25.95 12.07 25.95 6.2
14.80 7 1.05 7.34 14.80 15.5116 0.00105 2.24908 35 7 20 14.21 25.95 11.67 25.95 7.3
16.91 8 1.05 8.39 16.91 17.7276 0.00075 1.82149 32 6 16 14.65 25.95 11.28 25.95 8.3
19.03 9 1.05 9.43 19.03 18.8356 0.00045 1.2219 23 5 9 12.57 22.68 10.88 25.95 9.4
21.14 10 1.05 10.48 21.14 21.0515 0.00015 0.4503 9 4 3 10.48 19.41 10.48 25.95 10.4
S 10.48 115 208 134
2ND ESTIMATE
Axial load Pu = 225 kDistance to neutral axis c = 5 in
Beta factor b = 0.85
Compression block a = 5 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.001 34 0 11 0
2 0.91 6.51 -0.001 -20 -18 7 -11
3 1.83 9.79 -0.003 -61 -111 4 -37
4 0.97 13.07 -0.004 -61 -59 1 -35 0.12 13.42 -0.005 -61 -7 0 0
6 0.12 13.76 -0.005 -61 -7 0 0
7 0.12 14.10 -0.005 -61 -7 0 0
8 0.53 14.44 -0.005 -61 -32 -1 2
9 0.93 17.02 -0.007 -61 -57 -3 15
10 0.93 19.60 -0.008 -61 -57 -6 28
11 0.93 22.18 -0.010 -61 -57 -8 40
12 0.47 24.76 -0.011 -61 -28 -11 26
CONC 53 47
S -389 107
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b controlDA
ec fc force arm moment to end b to end b to en5.55 1 0.53 0.53 1.07 0.00 0.28299 0.00285 2.58825 1 13 1 3.22 6.49 3.22 6.49 0.5
11.10 2 0.53 1.06 2.14 12.86 0.84897 0.00255 2.58825 2 13 2 6.43 12.97 6.43 12.97 1.0
16.65 3 0.53 1.59 3.21 14.65 1.41496 0.00225 2.58825 4 12 4 9.65 19.46 9.65 19.46 1.5
22.20 4 0.53 2.12 4.27 27.52 1.98094 0.00195 2.58825 5 12 5 12.86 25.95 12.86 25.95 2.1
27.75 5 0.53 2.65 5.34 2.82991 0.00165 2.58825 7 11 7 13.31 25.95 11.60 25.95 2.6
33.30 6 0.53 3.18 6.41 3.3959 0.00135 2.50466 9 11 8 13.76 25.95 10.34 25.95 3.1
38.85 7 0.53 3.71 7.48 3.96188 0.00105 2.24908 9 10 8 14.21 25.95 9.08 25.95 3.7
44.40 8 0.53 4.24 8.55 4.52786 0.00075 1.82149 8 10 7 14.65 25.95 7.82 25.95 4.2
49.96 9 0.53 4.77 9.62 4.81085 0.00045 1.2219 6 9 5 9.98 25.63 6.56 25.95 4.7
55.51 10 0.53 5.30 10.68 5.37684 0.00015 0.4503 2 9 2 5.30 25.31 5.30 25.95 5.3
case 2
case 2
e 3 case 1
e 3 case 1
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
31/45
S 5.30 29 53 47
4TH ITERATION
Axial load Pu = 225 k
Distance to neutral axis c = 13 in
Beta factor b = 0.85
Compression block a = 11 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc'
= 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 43 37 7 22
3 1.83 9.79 0.001 21 33 4 11
4 0.97 13.07 0.000 -1 -1 1 0
5 0.12 13.42 0.000 -4 0 0 0
6 0.12 13.76 0.000 -6 -1 0 0
7 0.12 14.10 0.000 -8 -1 0 0
8 0.53 14.44 0.000 -11 -6 -1 0
9 0.93 17.02 -0.001 -28 -26 -3 7
10 0.93 19.60 -0.002 -46 -43 -6 21
11 0.93 22.18 -0.002 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 312 167
S 219 294
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control DA ec fc force arm moment to end b to end b to en
2.84 1 1.29 1.29 2.59 0.00 1.66778 0.00285 2.58825 4 13 5 3.22 6.49 3.22 6.49 1.2
5.67 2 1.29 2.57 5.19 12.86 5.00334 0.00255 2.58825 13 12 13 6.43 12.97 6.43 12.97 2.5
8.51 3 1.29 3.86 7.78 14.65 8.33889 0.00225 2.58825 22 11 19 9.65 19.46 9.65 19.46 3.8
11.34 4 1.29 5.14 10.38 27.52 11.6744 0.00195 2.58825 30 9 23 12.86 25.95 12.86 25.95 5.1
14.18 5 1.29 6.43 12.97 16.6778 0.00165 2.58825 43 8 29 13.31 25.95 12.86 25.95 6.4
17.01 6 1.29 7.72 15.56 20.0133 0.00135 2.50466 50 7 28 13.76 25.95 12.86 25.95 7.7
19.85 7 1.29 9.00 18.16 23.3489 0.00105 2.24908 53 5 24 14.21 25.95 12.86 25.95 9.0
22.68 8 1.29 10.29 20.75 26.6845 0.00075 1.82149 49 4 17 14.65 25.95 12.86 25.95 10.2
25.52 9 1.29 11.57 23.34 28.3522 0.00045 1.2219 35 3 8 13.76 21.32 12.86 25.95 11.5
28.35 10 1.29 12.86 25.94 31.6878 0.00015 0.4503 14 2 2 12.86 16.70 12.86 25.95 12.8
S 12.86 173 312 167
6TH ITERATION
Axial load Pu = 225 k
Distance to neutral axis c = 12 in
Beta factor b = 0.85
Compression block a = 11 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 41 35 7 21
3 1.83 9.79 0.001 18 29 4 9
4 0.97 13.07 0.000 -5 -5 1 0
5 0.12 13.42 0.000 -7 -1 0 0
6 0.12 13.76 0.000 -10 -1 0 0
7 0.12 14.10 0.000 -12 -1 0 0
8 0.53 14.44 0.000 -14 -8 -1 0
9 0.93 17.02 -0.001 -32 -30 -3 8
10 0.93 19.60 -0.002 -51 -47 -6 2311 0.93 22.18 -0.002 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 290 161
S 176 290
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control DA ec fc force arm moment to end b to end b to en
2.61 1 1.24 1.24 2.50 0.00 1.55074 0.00285 2.58825 4 13 4 3.22 6.49 3.22 6.49 1.2
5.22 2 1.24 2.48 5.00 12.86 4.65222 0.00255 2.58825 12 12 12 6.43 12.97 6.43 12.97 2.4
7.82 3 1.24 3.72 7.50 14.65 7.75369 0.00225 2.58825 20 11 18 9.65 19.46 9.65 19.46 3.7
e 3 case 1
e 3 case 1
case 2
case 2
-
7/30/2019 ACI318-08 Columna Rectangular Biaxial
32/45
10.43 4 1.24 4.96 10.00 27.52 10.8552 0.00195 2.58825 28 9 22 12.86 25.95 12.86 25.95 4.9
13.04 5 1.24 6.20 12.51 15.5074 0.00165 2.58825 40 8 27 13.31 25.95 12.79 25.95 6.2
15.65 6 1.24 7.44 15.01 18.6089 0.00135 2.50466 47 7 27 13.76 25.95 12.71 25.95 7.44
18.25 7 1.24 8.68 17.51 21.7103 0.00105 2.24908 49 6 23 14.21 25.95 12.63 25.95 8.6
20.86 8 1.24 9.92 20.01 24.8118 0.00075 1.82149 45 4 17 14.65 25.95 12.56 25.95 9.9
23.47 9 1.24 11.16 22.51 26.3626 0.00045 1.2219 32 3 9 13.53 21.58 12.48 25.95 11.1
26.08 10 1.24 12.40 25.01 29.464 0.00015 0.4503 13 2 2 12.40 17.22 12.40 25.95 12.4
S 12.40 161 290 161
8TH ITERATION
Axial load Pu = 225 k
Distance to neutral axis c = 13 in
Beta factor b = 0.85
Compression block a = 11 in
E = 29000 ksi d = 25 in
fy = 61 ksi D = 28 in
fc' = 3 ksi q = 41.28
STA A dist strain stress force arm moment
to end
1 0.00 3.23 0.002 61 0 11 0
2 0.91 6.51 0.001 43 37 7 23
3 1.83 9.79 0.001 21 35 4 11
4 0.97 13.07 0.000 0 0 1 0
5 0.12 13.42 0.000 -3 0 0 0
6 0.12 13.76 0.000 -5 -1 0 0
7 0.12 14.10 0.000 -7 -1 0 0
8 0.53 14.44 0.000 -10 -5 -1 0
9 0.93 17.02 -0.001 -27 -25 -3 7
10 0.93 19.60 -0.002 -44 -41 -6 20
11 0.93 22.18 -0.002 -61 -57 -8 40
12 0.47 24.76 -0.003 -61 -28 -11 26
CONC 312 163
S 225 290
Ec = 3145 ksi eo = 0.0016
b conc sec thick to end b control DA ec fc force arm moment to end b to end b to en
2.62 1 3.22 3.22 6.49 0.00 10.4315 0.00263 2.58825 27 12 27 3.22 6.49 3.22 6.49 1.3
5.25 2 3.22 6.43 12.97 12.86 31.2944 0.00189 2.58825 81 9 60 6.43 12.97 6.43 12.97 2.6
7.87 3 3.22 9.65 19.46 14.65 52.1574 0.00115 2.34871 123 6 58 9.65 19.46 9.65 19.46 3.9
10.50 4 3.22 12.86 25.95 27.52 73.0203 0.0004 1.11269 81 3 17 12.86 25.95 12.86 25.95 5.2
13.12 5 0.02 12.89 25.95 0.6027 2.9E-05 0.09187 0 1 0 13.31 25.95 12.89 25.95 6.5
15.75 6 0.02 12.91 25.95 0.6027 2.4E-05 0.07529 0 1 0 13.76 25.95 12.91 25.95 7.8
18.37 7 0.02 12.93 25.95 0.6027 1.9E-05 0.05865 0 1 0 14.21 25.95 12.93 25.95 9.1
21.00 8 0.02 12.96 25.95 0.6027 1.3E-05 0.04196 0 1 0 14.65 25.95 12.96 25.95 10.4
23.62 9 0.02 12.98 25.95 0.6027 8E-06 0.02522 0 1 0 13.83 21.24 12.98 25.95 11.7
26.25 10 0.02 13.00 25.95 0.6027 2.7E-06 0.00842 0 1 0 13.00 16.53 13.00 25.95 13.0
S 13.00 171 312 163
case 2 e 3 case 1
-
7/30/2019 ACI318-08 Colu