Single Footing Design - Telecomm, Transmission & Guyed Tower & Pole - TIA 222F & ACI

7/22/2019 Single Footing Design - Telecomm, Transmission & Guyed Tower & Pole - TIA 222F & ACI

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A. GENERAL

1 Tower Height (m) = 72 m

2 Soil Class =

B. LOADINGS, Unfactored

Vertical load (kN) All VALUES ARE UNFACTORED

Condition Hx - kN Hy - kN F - kN

Max Compression = 47.939 46.269 745.950

Max Tension = -48.016 -48.228 -617.464

C. MATERIAL PROPERTIES

1 Soil angle of friction / frustum angle () = 250

[But this value should be EXACTLY 30 per TIA

2 Soil density (gs) = 1600 kg/m3 = 15.70 kN/m3 [But this v

3 Allowable soil bearing cap (all) = 1 kg/cm2

= 98.10 kN/m2

4 Concrete density (gc) = 2400 kg/m3

= 23.54 kN/m3

5 Surcharge (If any) Sur = 0.1 kg/cm2

= 9.81 kN/m2

6 Soil Type = Clean fine sand, silty or clayey fine to medium sand.

7 Soil angle of friction (Drained condition) (') = 250

8 Soil angle of friction (Undrained condition) (T) =0

D. DIMENSIONS

1 Pad / Footing

Footing Outer width / Length (BO) = 4.25 m

Footing Thickness (hp) or (T) = 0.5 m

2 Overall soil depth, above pad (h) = 2.45 m

Height of chimney above GL (h1) = 0.4 m

3 Chimney / Pedestal size/width (bc) = 0.6 m

4 Min of tower base width (Bb) = 7 m

5 Total depth (hp+h) = 2.95 m

5 Checking of free space between soil frustum, at GL

Add, width, due to soil frustum (Ba) = 1.14 m

Free space (sf) = -1.61 < 0 use eff frustum angle

Effective add width, due to soil frustum (Ba') = 1.14 m

Effective soil frustum angle (') = 25O

Width total frustum (Bt) = 6.53

E. UPLIFT CAPACITY

1 Concrete

Volume above GL (Vch1) = 0.14 m

Volume within frustum (Vch2) = 0.882 m

Volume below frustum (Vp) = 9.03125 m3

Vol. chimney / Pedestal (Vch1+Vch2) = 1.03 m

Counter Weight (Not Surcharge) (Cw) = 0.00 m3

Vol concrete total (Vc) = 10.06 m

Concrete weigth (Wc) = 236.79 kN

2 Soil Weight Calculation

A Method A

Volume Soil Cone (Vcone) = 29.05 m Eq OK

Volume of Soil just above the footing (Vsoil) = 43.37 m

Total Volume Soil (Vs) = 72.42 m

Soil weight (Method A, Ws) = 1137 kN

B Method B

Volume Soil Cone Qu = 14.73 m3

Single footing - Subjected to Compressive & Tensile Force (P), Shear Force (V) (No Moment)

Design Code TIA/EIA 222 F, ACI 318-99)

DESIGN CALCULATION OF

M=HR.h

Bo

hp

h

h1Ba

Bt

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Volume of Soil just above the footing (Vsoil) = 43.37 m

Total Volume Soil (Vs) = 58.10 m

Soil weight (Method B, Ws) = 912 kN [Coefficient of lateral earth pressure K = 0.5]

Total Soil Volume (Smaller of Method A & B) 912 kNSo Final Soil weight (Ws) = 912 kN

3 Checking of uplift Capacity

Total weight resisting uplift (Wc+Ws) = 1149 kN > 617.464 kN 1.86

222F Code provision for uplift Check - 1 (Wc+Ws)/1.5 = 766 > 617.464 ...OK

222F Code provision for uplift Check - 2 (Wc/1.25+Ws/2) = 645 > 617.464 ...OK

F. BEARING CAPACITY

1 Vertical Load from tower base (Downward) (Fc) = 745.95 kN

Concrete weight (Excluding soil weight) (Wc') = 78.93 kN

Maximum vertical load - (Compression Force) N max = 824.88 kN

Minimum vertical load - (Tension Force) N min = Tension force need NOT to be checked for bearing, if compression

Wind load combined with Load Combination? = Yes

2 Bending momnet, due to Sliding / Shear force

My = 160.60 kN e1 or ex = 0.195 Bo/6 = 0.708

Mx = 155.00 kN e2 or ey = 0.188 Bo/6 = 0.708

A Remember, Here footing has been designed for ONE WAY ECCENTRICITY (Uniaxial Moment), SO it should be checked for Mx,ex first

then again in another calculation the footing should be checked for My, ey (Here calculation for My, ey has not been shown)

(max) = 67.59 < 130.47 kN/m2 ...OK

qs = surcharge

T = Footing thickness

(min) = 43.36 < 130.47 kN/m2 ...OK

B For TWO WAY ECCENTRICITY (Biaxial Moment), below eq 1 must be satisfied FIRST. Most tower has biaxial moment for single

footing / Pile. If eq 1) passes then use eq 2) to calculate the footing's 4 corner pressure, otherwise increase footing size.

Eq 1) If this dont satisfy then increase footing size

Here, Wf Weigth of footing

c1 & c2 B and L

Eq 2) ( another eq is max = P / Az + P*e1*c1/I1 + P*e2*c2/I2)

(max) = 70.34 kN/m2

< 130.47 kN/m2

...OK

G. SLIDING (Sliding is important for Tower, specially Monopole or guyed pole or tapered pole)

Coefficient of friction, From table = 0.35 - 0.45 Input manually

Coefficient of friction, From Eq = tan (0.7*')

= 0.296

Finally use = 0.35

Allowable Coefficient of friction (SF = 1.5 ~ 2) a = / SF

a = 0.233

( )

( )

61

0.15 ,6

20.15 ,

3 (0.5 ) 6

ss

MAX

ss

eP

LLT for eq w

q BL

P LT for eq w

B L e

+

++-=

++->-

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Alloable equivalent passive fluid density a = Page 278, Donald P. Coduto

a = 113.193 lb/ft2 Foundation Design, Pprinciples and Practice

Note Factor of safety for is 1.5 to 2

Note Factor of safety for is 2 to 3

Here is 110 cft

Vfa =

Case 1, Considering Compression Force, Down Downward P = 167.70 kip Page 278, Donald P. Coduto

Case 2, Considering Tension Force, Upward Upward P = -138.81 kip Foundation Design, Pprinciples and Practice

Footing Weight = 17.74 kip

Footing Length B 13.94 ft

Footing Depth 9.68 ft

Developed shear at tower / pole / guy leg. V = 10.79 kip

Case 1 Vfa, case 1 = 117.20 kip < V ok

Case 2 Vfa, case 2 = 45.68 kip < V ok

Factor of safety SF (Min 1.5 by TIA 222F code) SF (Case 1) = = 10.86

Factor of safety SF (Min 1.5 by TIA 222F code) SF (Case 2) = = 4.23

H. OVERTURNING MOMENT

1 Resultan horizontal load (HR) = 66.63 kN

2 Moment overturning (Mov) = 223.20 kN < 1128.92 kN3 Moment resisting (Mres) = 1128.92 kN

4 Factor of safety SF (Min 1.5 by TIA 222F code) SF = 5.06 > 1.50 ok

I. DESIGN OF PAD

1 Concrete cover (d') = 70 mm

2 Material Grade

Concrete K-175 (fc') = 20.68 MPa 3.00 ksi

Steel Reinforcing Bar (U-39) (fy) = 413 MPa 59.90 ksi

3 Bending Moment

Pad cantilever length (lc) = 1.825 m

Compression

Soil pressure at the perpendicular side of chimney

Maximum (c)max = 67.59 kN/m2

Minimum (c)min = 43.36 kN/m2

Ultimate bending moment (Mu) = 99.11 kNm for 1 m' span

Uplift

Soil pressure at the perpendicular side of chimney

Design uplift pressure (up) = -34.18 kN/m2

Ultimate bending moment (Mu) = -56.93 kNm for 1 m' span

4 Reinforced concrete design for bending

min = 0.00366

max = 0.75*b

max = 0.01607

= 0.85 = 0.8

Upper pad

Mn (Mu/) = -71.16 kN db = 16 mm

Design width (b) = 1000 mm As1 = 201.06 mm2

Effective depth (d) = 430 mm

Rn Rn=Mn/bd2

= -0.38

Required area ratio of bar (req) = -0.0024

Required area of bar (Asreq) = -1042.35 mm

Spacing s=As1/Asreqxb = -192.89 mm Use D 16 - 136

Lower pad

Mn (Mu/) = 123.89 kN db = 16 mm

Design width (b) = 1000 mm As1 = 201.06 mm2

Effective depth (d) = 430 mm

Rn Rn=Mn/bd2

= 0.67

Required area ratio of bar (req) = 0.0042 Use 0.004220356

Required area of bar (Asreq) = 1814.75 mm

Spacing s=As1/Asreqxb = 110.79 mm Use D 16 - 136

nos = 30.22 Use 22

Development length

Minimun development length = 300 mm

Below p arts havent yet been checked.

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Basic 0.02.As.fy/(fc')0.5

= 365 mm

Minimum 0.06.db.fy = 11 mm

Available development length ldb = 430 mm

5 Concrete Bearing Capacity

A1 = 0.36 m ab = 2

A2 = 18.0625 m2

f = 0.7

Max load on the center of cap, (Fc)ver+Wch = 766.72 kN

Concrete Bearing Capacity f.0.85.fc'(ab.A1) = #REF! kN #REF! (Fc)ver+Wch #REF!

6 Checking of one-way shear along Section A-A (eff. Face chimney)

Strength reduction factor (f) = 0.65Compression

Web width (bw) = 4250.00 mm

Effective depth (d) = 430.00 mm

Factored shear force (Vu) = 79.25 kN

(Vc) = 1024.596 kN

(fVc) = 665.987 kN > Vu ...OK

Uplift

Factored shear force (Vu) = -62.473 kN

(fVc) = 665.987 kN > Vu ...OK

7 Checking of Punching Shear

bc = 1 (f) = 0.65

as = 20 (for corner colomn)

Compression

Chimney width (bc) = 0.6 m

Effective depth (d) = 0.43 m

Perimeter length (bo)=4.(bc+d) (bo) = 4.12 m

Factored shear force Vu=(c)(B2-(bc+d)

2) (Vu) = 1149.19 kN

Concrete shear strength (Vc) is the smallest amount of :

= 4028.20 kN

= 2744.13 kN

(Vc)min = 2685.47 kN

(fVc) = 1745.55 kN

= 2685.47 kN

(fVc) = 1745.55 kN > (Vu) ...OK

Uplift

Chimney width (bc) = 0.6 m

Effective depth (d) = 0.43 m

Chimney concrete cover (d') = 0.07 m

Perimeter length (bo)=4.(bc+d-2d') (bo) = 3.56 m

Factored shear force Vu=(up)(bo2-(bc-2d)

2) (Vu) = -430.93 kN

Concrete shear strength (Vc) is the smallest amount of :

= #REF! kN

= #REF! kN

(Vc)min = #REF! kN

(fVc) = #REF! kN

= #REF! kN

(fVc) = #REF! kN #REF! (Vu) #REF!

dbfV wcc '61=

12

42

' dbfV occ

c

+=

b

122

' dbf

b

daV oc

o

sc

+=

124

' d

bfV occ =

12

42

' dbfV occ

c

+=

b

122

' dbfb

daV oc

o

sc

+=

124

' d

bfV occ =

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J. DESIGN OF CHIMNEY

1 Material Grades

Concrete K225 (fc') = 18.63 MPa

Steel reinforcement bar (fy) = 413 MPa

2 Slenderness Evaluation

bc = 0.6 m k = 1

lu = 2.85 m r = 0.173 m

I = 0.0108 m4

A = 0.36 m2

For a braced frame klu/r = 16.454 < 34 ...OK

3 Axial and Moment Forces

Compression

Ru' = 66.63 kN

Pu' = 745.95 kN

Mu' = 189.88 kN.m

Uplift

Ru = 68.05 kN

Pu = -617.46 kN

Mu = 193.96 kN.m

4 Longitudinal Bar Design

rmin = 0.0034 b = 0.85

rmax = 0.0145 f = 0.8

According to Column interaction chart, available rebar

Number of rebar = 20 nos

Diameter of rebar = 16 mm Asreq = 0.000201062 m

rmin < r = 0.0112 < rmax OK

Development length

Minimum development length 8db = 128 mm or 155 mm

90 degrees standar hook = 259 mm

Available development length = 1825 mm > 128 mm OK

5 Stirrup Design

Steel U-24 fy = 240 MPa db = 10 mm

f = 0.65 Av = 0.000157 m

(Vu) = 66.626 kN

(fVs) = 133.204 kN

(fVc) = 604.185 kN

Maximum shear load for stirrup (fVs)max = 2134.788 kN > (fVs) OK

Maximum spacing smax = 250 mm Use D 10 - 150

(fVc)+(fVs) > (Vu) OK

K. Sloof

Ps = (60%P) = 447.570 kN

Steel U-39 fy = 413 MPa nos = 8

bs = 0.3 m dbs = 16

hs = 0.5 m

Depth of sloof hsl = 0.3 m

Minimum base width of tower Bb = 7 m

664.309 kN > 447.570 kN OK

Stirrup Design

fy = 240 MPa db = 10 mm

f = 0.65 Av = 0.000157 m

Maximum spacing smax = 250 mm Use D 10 - 200

dbfV wcc'

6

1=

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L. ESTIMATED VOLUME OF MATERIALS

1 Volume of concrete K-225 One leg = 11.11 m3

2 Weight of steel bar

Pad

Lower Use 22 D 16 1.58 kg/m =

Upper Use 22 D 16 1.58 kg/m =

3 Chimney

Longitudinal bar Use 20 D 16 1.58 kg/m =

Stirrup Use D 10 -150 0.62 kg/m =

4 Sloof Use 8 D 16 1.58 kg/m =

Use D 10 -200 0.62 kg/m =

Total =

5 Total 4 (four) leg of lattice tower

Volume of concrete K-175 = 44.43 m3

Weight of steel bar = 2400.83 kg

6 Excavation soil volume

One leg (EVs) = 11.59 m

One tower (EVs) = 46.37 m

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222F]

alue EXACTLY 16 kN/m3 per TIA 222F]

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use this SF for RCC building design

asses

...OK

...OK

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s

s

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172.76 kg

172.76 kg

90.06 kg

20.15 kg

88.48 kg

56.00 kg

600.21 kg

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Documents

Single Footing Design - Telecomm, Transmission & Guyed Tower & Pole - TIA 222F & ACI