EMPLOYER :
POWER GRID COMPANY OF BANGLADESH LIMITED (PGCB ) CONTRACT NO. : PGCB/DANIDA/1
DESIGN-BUILD AND TURNKEY CONTRACT FOR CONSTRUCTION OF 132kV JOYDEVPUR - KABIRPUR - TANGAIL TRANSMISSION LINE PROJECT TI TL E :
Design Calculation for Foundation of Auto Transformer D O CU M E N T N O . :
S U B M I T T A L N O. :
JDP/A26/001
S E CT CT I O N : 1 2 , Building and civil engineering works
DESIGNED BY : Md. Giasuddin
CH E C K E D B Y :
A P P R OV E D B Y :
R EV . N O. :
M A N U F A CT U R E R :
DATE :
19 Nov '05
Paper Size A4
E:\PROJECTS FOR EXECUTION\Joydevpur - Kabirpur Tangail OHL\Joydevpur Substation\Design Calculation\Static Cal of Foundation For Auto Transformer
CONTRACTOR : MTH
JGAARD A/S - LINDPRO A/S JV
ID:
r o e s u , n o i t c u d o r . p n e e R d d . i n b i r e r o e f y h t l t c n i o r t i s a s i m r y t o i f r n o i h e t h t u a d s n s a e t r p n x e e m t u u c o o t d h i s w i h s t e n i t i r a s t p h d g r i i r h l l t a o e t v r e r e u s s e o r l c e i s W d
EMPLOYER :
POWER GRID COMPANY OF BANGLADESH LIMITED (PGCB ) CONTRACT NO. : PGCB/DANIDA/1
DESIGN-BUILD AND TURNKEY CONTRACT FOR CONSTRUCTION OF 132kV JOYDEVPUR - KABIRPUR - TANGAIL TRANSMISSION LINE PROJECT TI TL E :
Design Calculation for Foundation of Auto Transformer DOCUM EN T N O. :
SUBM I TTA L N O. :
JDP/A26/001
S E CT I O N : 1 2 , Building and civil engineering works
DESIGNED BY : Md. Giasuddin
CH ECK ED B Y :
A P P R OV ED BY :
REV. N O. :
M A N UFA CTURER :
DATE :
19 Nov '05
Paper Size A4
E:\PROJECTS FOR EXECUTION\Joydevpur - Kabirpur Tangail OHL\Joydevpur Substation\Design Calculation\Static Cal of Foundation For Auto Transformer
CONTRACTOR : MTH
JGAARD A/S - LINDPRO A/S JV
ID:
r o e s u , n o i t c u d o r . p n e e R d d . i n b i r e o r f e y h l t t c n i o r t i s a s i m r y t o i f n r o i h e t h t u a d s n s a e t r n p e x e m t u u c o o t d h i s w i h t s e n i t i r s a t p h d g r i r i h l l t a o e t v e r r e u s s e o r l c e i s W d
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station 1. GENERAL 1.1 Considerations : a) Raft foundation is considered for a 132kV Transformer. b) The bottom of the raft is at a depth of 1.0m from existing ground surface. 2
c) Soil bearing capacity is considered 90.04 kN/m minimum value from BH-4, BH-5 & BH-7. d) The Top of bund wall is 200mm above the finished switchyard surface level.
1.2 Soil Data: Allowable bearing capacity of soil is considered : Unit weight of soil : Frustum angle : Water Table from EGL :
90.04 kN/sqm 17.94 kN/cum. 15.00 Deg. 2.50 m
1.3Material Properties : Concrete………………...…fc'= Reinforcing Steel…………..f = Concrete Clear Cover……….= Unit Weight of Concrete…….=
20 N/mm2 415 N/mm2 60 mm 24.0 kN/cum.
2. DESIGN DATA AND FOUNDATI ON GEOMET RY : ( Reference Dwg no. 56.20.3-03-3537) Transformer's Length = 6.80 m Transformer's Width = 5.10 m Height of Transformer = 5.00 m Total Weight of Tx. ( with Oil ) = 72,000 Kg Weight of Oil = 19,000 Kg Density of Oil = 840 Kg/cum. Total volume of oil = 22.62 Cum Pit volume reqd. below the stone ( 125% of oil vol. ) = 28.27 Cum Inside length of pit considered = 7.80 m Inside width of pit considered = 5.80 m Surface area of the pit = 41.47 sqm. Width of Tx. Supporting Pedestal = 2.68 m Length of Tx. Supporting Pedestal = 3.89 m Area of Tx. Supporting Pedestal = 10.4 sqm. Net surface area of the pit = 31.0 sqm. Average Depth required = 0.9 m Provided depth below Grating = 0.90 m Thickness of grating = 0.05 m Thickness of gravel layer on top of grating = 0.225 m Free height above gravel top = 0.05 m Max. height of pit wall above base slab = 1.225 m Center of Tx.
Center of Foundation
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station Center of Foundation
3. LOA D CAL CULAT ION Transformer Length, L = 6.80 m Transformer Width, B = 5.10 m Transformer Height above top of Pedestal, H = 5.00 m Total weight of Transformer ( with oil ) = 720.00 kN
3.1 Wind load calculation - as per BNBC Maximum wind velocity , Vb = 160.0 km/hr Height of top of transformer from FSYL = 5.20 m
q z = cc c I c z v
( Specified in the Contract specification) ( Ref. Bangladesh National Building Code 1993, Chapter 2;Page 6-33)
2 b
For exposure B , Cz at Top = 0.85 For exposure B , Cz at Bottom = 0.801 Velocity to Pressure conversion coefficient, Cc = 4.72E-05 Structure Importance Factor CI = 1.25
q z = 1.284 kN/m2 = 1.210 kN/m2
Design Wind Pressure, p z = c Gc pq z
; at Top ; at Bottom ( Ref. Bangladesh National Building Code 1993, Chapter 2;Page 6-34)
L/B = 1.33 H/B = 0.98 , p .
-
Gust Co-efficient, CG = 1 .30
Design Wind Pressure, p z = 1.335 kN/m2 = 1.258 kN/m2 Average Pressure , Pz = 1.29671 kN/m2 ∴ Force results from Wind = 1.297*6.8*5.1 = 44.97 kN
; at Top ; at Bottom
3.2 Seismic load calculation - as per BNBC Design Base Shear is given by :
V
( Ref. Bangladesh National Building Code 1993, Chapter 2;Page 6-53) ( for Zone 2 ) ( with essential Facilities ) ( For RCC wall System )
ZICW =
R
Where, Z = Seismic Zone Co-efficient = 0.15 I = Structure Importance Factor = 1.25 R = Response Modification Coefficient = 6 C = Numerical coefficien t system is given by : C =
1.25S
T
2
3
S = Site coefficient for soil characteristics = 1.5 T = Fundamental period of vibration is given by : T = Ct ( hn ) Ct = 0.049
3
4
( For all type of non braced RCC structure )
hn = 5.00 m T = 0.164 Sec C = 6.262 W = Total Seismic dead load =Transformer Weight = 720.00 kN Design base shear V = 140.90 kN
4. SOIL STABI LI TY CHECK
828.0 kN
4.1 Check for Soil Bearing Capacity : Weight of each Transformer with 15% impact = 828.00 kN Weight of Transformer supporting Pedestal = 306.50 kN Length of foundation pad = 8.800 m Width of foundation pad = 6.800 m Thickness of foundation pad = 0.300 m
140.0 kN
CL of Foundation
Load Application on Foundation
MT H J GAARD A/S - L INDPRO A/S J V
CL of Foundation
Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station Weight of Pad = 430.85 kN Width of Bund Wall = 0.200 m Total Length of Bund wall = 28.540 m Height of Bund wall = 1.225 m Weight of Bund wall = 167.82 kN Total area of the Yard within bundwall = 41.47 m2 Area of Tx. supporting Pedestal = 10.43 m2 Net area to be filled with gravel = 31.04 m2 Thickness of Gravel = 0.225 m Weight of gravel = 111.76 kN
Load Application on Foundation
Total Vertical Load = 828+306.5 +430.85+167 .82+111.76 = 1844.93 kN Maximum Moment at base due to Max. Horizontal Load =140.9*1.525 = 214.87 kN.m Eccentricity for Horizontal load = 214.87/1844.93 = 0.116 m Net Eccentricity = 0.116+0.600 = 0.716 m Q = Fzb = 1844.93 kN kNs A = LxB = 59.84
2
m
e = el = 0.716 m
m
L /6 = 1.467
>e
6e (1+ ) A L Q 6e = (1) A L
So;q max = and;q min
Q
qmax = 43.54 kN/m2 Gross allowable soil pressure = 90.04 + γsDf = 107.98 kN/m2
So it's OK.
Net Upward Pressure = 43.54-γ'sDf = 35.60 kN/m2
4.2 Check for Settlement : Settlement of a Soil layer is given by :
S=
cc p + Δp H log10 0 1 + e0 p0 Where, Cc = Compression Index = 0.258
e0 = Initial Void ratio = 0.989 H = Thickness of the Soil Layer = 5.00 m p0 = The original Soil Pressure at the mid point of the
From soil test report of BH-4. From soil test report of BH-4. From soil test report of BH-4.
layer = γ∗H/2 = 45.00 kN/m2 Δ p = Change In Pressure = qmax - γDf = 25.60 kN/m2
S = 0.1269 ft. = 1.524 inch. Which is less than 2.0" , so OK.
5. STRUC TURA L DESIGN 5.1 Design of Pit Wall : Angle of repose for backfilled soil, φ = 0.00 Deg Coefficient of earth pressure , Ka = ( 1-sin φ ) / ( 1-sin φ ) = 1.00 Unit weight of soil = 17.94 kN/cum Height of soil at toe side above base = 0.000 m Height of soil at heel side above slab = 0.700 m PL above heel side soil = 0.200 m Thickness of stem = 0.200 m Thickness of base slab = 0.300 m Superimposed live load at heel side = 10.00 kN/sqm
Applied L oading : Unit Weight of Gravel Fill = 16 kN/cum. Unit Weight of Brick = 19 kN/cum. Unit Weight of Sand Fill = 15 kN/cum. 2
Pressure due to Backfill P1= 1/2*K pγh *1.0 = 4.40 kN
( Per meter of width )
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station ( For Backfill φ is considered 0 Degree ) K a = ( 1-Sinφ )/( 1+Sinφ ) = 1.0 Pressure due Surcharge load P2 =10.0+ ( 0.175*16+0.075*19+0.075*15)*0.7 = 13.75 kN ( Per meter of width ) So Moment about point A = 4.41*0.233+13.75*0.35 = 5.835 kN.m ( Per meter of width ) Factored Moment = 5.838*1.5 = 8.752 kN.m " Let us check with minimum reinforcement. As per ACI code, Ratio of minimum reinforcement ( in SI unit) is given by =1.4/fy
ρmin= 0.003373494 ρf y ⎛ M u =φρf y bd 2 ⎜1-0.59 f'c ⎝ ∴
⎞ ⎟ ...;Where ⎠
Mu
d=
φρf y b(1-0.59
ρf y
fc'
φ
= )
= 0.9
; d Provided =200-100-10/2= 95 mm; OK
85 mm
5.1.1 - R einforcement Calculation : Vertical Reinforcement Mdes =Mu/0.9 = 9.725 kN.m Assuming depth of stress block, a = 6.94 mm Area of steel, As = M*1000000/(0.9*fy*(d-a/2)) = 284.47 mm2 (Ref. -Design of concrete structure, By-Nilson & Winter,Page 83 ,10th Ed.)
Check for a a = As*fy/(.85*fc'*b) = 6.94 mm Consideration is OK, So As = 284.47 mm2/m As per Code Min Rebar Required = 0.004bt = 400.00 mm2/m Consider bar Size = 10.0 mm So Nos. of Bars = 5 Nos Spacing = 200.00 mm Provide φ 10mm @ 200mm at both face of the wall.
Horizontal Reinforcement : As per Code Min Rebar Required = 0.002bt = 400.00 mm2/m Consider bar Size = 10.0 mm So Nos. of Bars = 5 Nos Spacing = 1000/5 = 200.00 mm Provide φ 10mm @ 200mm at both face of the wall.
Check for shear : Shear force , V = 18.14 kN Factored shear , Vu = 27.21 kN Where, b= 1000 mm d = 95 mm So, vc= Vc/bd = 0.286 N/mm2 AS per ACI Shear Stress applied to concrete should be less than
0.17 f c '
This is much greater than applied stress so consideration is quite Ok.
5.2 Design of Transformer Supporting Pedestal : ( Reference Dwg no. 56.20.3-03-3537) Length of Pedestal = 3.890 m Width of Pedestal = 2.680 m Hight of Pedestal = 1.225 m Weight of Pedestal = 306.50 kN Total Weight of Tx. ( with Oil ) = 720.00 kN
Design L oads: Compression =720.0+306.5 = 1026.50 kN Moment M = 172.6025
Max. or Min. stress on the section =
σ
max/min
=
P A
±
Mc I
3
I = bh /12 = 6.24E+12 mm4 Maximum stress on the section = 0.06 Mpa, Compressive Stresse is within acceptable limit, so no rebar is r equired from structural point of view.
2
N/mm ; In present case which is coming 0.76 Mpa.
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station 2
2
But as per code Minimun Rebar = 0.0018*Ag = 0.0018*3890*2680 mm . = 18766 mm . So Use 94 nos. of dia 16mm Bar for Vertical Reinforcement. Use dia 10mm bar @ 200mm c/c for tie.
5.3. Design of Base Slab Foundation Layout Center of Tx.
Center of Foundation
5.3.1 Check for P unching of the Base : Base Thickness, t = 300 mm Clear Cover = 60 mm Consider Max Bar size = 20 mm
d =300-60-20/2 = 230 mm Punching Perimeter = (2680+3890)*2 = 13140 mm Punching Area = 13140*230 = 3022200 mm2 Vertical Forces = 1026.50 kN Punching stress developed by Tx. = 1026.5*1000/ 3022200 = 0.340 Mpa AS per ACI Shear Stress applied to concrete should be less than
0.33
f c '
Mpa
In present case which is coming 1.48 Mpa. So OK.
5.3.2 Bottom Reinforcement Along L ong Direction : For right side Net Upward Pressure by soil = 35.60 kN/m2 Max Moment Developed at Pedestal face at Bottom = 35.6*3.055^2/2 = 166.147 kN.m/m Design moment = 170.42/0.9 = 184.607 kN.m/m Base Thickness, t = 300 mm Clear Cover = 60 mm Consider Bar size = 20 mm
d =300-60-20/2 = 230 mm Assuming depth of stress block, a = 60.39 mm Area of steel, As = M*1000000/(0.9*fy*(d-a/2)) = 2473.73 mm2
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station Check for stress block,a a = As*fy/(0.85*fc'*b) = 60.39 mm Consideration is OK, So As = 2473.73 mm2 Minimum reinforcement = 0.18 % = 540.00 mm2/m
Consider bar Size = 20 mm So Nos. of Bars = 7.87 Nos
Spacing = 127 mm
Say 120mm
For L eft Side Max Moment Developed at Pedestal face at Bottom = 35.6*1.855^2/2 = 61.257 kN.m/m Design moment = 61.257/0.9 = 68.063 kN.m/m Base Thickness, t = 300 mm Clear Cover = 60 mm Consider Bar size = 20 mm
d =300-60-20/2 = 230 mm Assuming depth of stress block, a = 20.23 mm Area of steel, As = M*1000000/(0.9*fy*(d-a/2)) = 828.76 mm2 Check for stress block,a a = As*fy/(0.85*fc'*b) = 20.23 mm Consideration is OK, So As = 828.76 mm2 Minimum reinforcement = 0.18 % = 540.00 mm2/m
Consider bar Size = 20 mm So Nos. of Bars = 2.64 Nos
Spacing = 379 mm
Say 240mm
5.3.3 Bottom Reinforcement Along Short Direction : Net Upward Pressure by soil = 43.54 -γ'sDf = 35.60 kN/m2 Max Moment Developed at Pedestal face at Bottom = 35.6*2.16^2/2 = 83.057 kN.m/m Design moment = 83.057/0.9 = 92.286 kN.m/m Base Thickness, t = 300 mm Clear Cover = 60 mm Consider Bar size = 12 mm d =300-60-12/2-20 =214 mm ( Bars to be placed on top of long Bars) Assuming depth of stress block, a = 30.34 mm Area of steel, As = M*1000000/(0.9*fy*(d-a/2)) = 1242.69 mm2 Check for stress block,a a = As*fy/(0.85*fc'*b) = 30.34 mm Consideration is OK, So As = 1242.69 mm2 Minimum reinforcement = 0.18 % = 540.00 mm2/m
Consider bar Size = 12 mm So Nos. of Bars = 10.99 Nos
Spacing = 91 mm
Say 90 mm
Calculation For Bar Curtailment Max Moment Developed at 0.75 m far from Pedestal face at Bottom = 35.6*1.41^2/2 = 35.392 kN.m/m Design moment = 35.392/0.9 = 39.325 kN.m/m Base Thickness, t = 300 mm Clear Cover = 60 mm Consider Bar size = 12 mm d =300-60-12/2-20 =214 mm ( Bars to be placed on top of long Bars) Assuming depth of stress block, a = 12.37 mm Area of steel, As = M*1000000/(0.9*fy*(d-a/2)) = 506.64 mm2 Check for stress block,a a = As*fy/(0.85*fc'*b) = 12.37 mm Consideration is OK, So As = 506.64 mm2 Minimum reinforcement = 0.18 % = 540.00 mm2/m
Consider bar Size = 12 mm So Nos. of Bars = 4.77 Nos
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station Spacing = 209 mm
Say 180 mm
Point of curtailment = 750+(12 times dia of bar ; i.e 12*12 = 144mm use 250mm) 250 = 1000mm from face of Padestal.
5.3.4 Top Reinforcement Calculation along both direction : Max Hogging Moment Developed = 35.6*( 3.0550.40)^2/8 = 31.368 kN.m/m Design moment = 27.165/0.9 = 34.854 kN.m/m Base Thickness, t = 300 mm Clear Cover = 60 mm Consider Max Bar size = 12 mm
d =300-60-12/2 = 234 mm Assuming depth of stress block, a = 9.95 mm Area of steel, As = M*1000000/(0.9*fy*(d-a/2)) = 407.45 mm2 Check for stress block,a a = As*fy/(0.85*fc'*b) = 9.95 mm Consideration is OK, So As = 407.45 mm2 Minimum reinforcement = 0.18 % = 540.00 mm2/m
Consider bar Size = 12 mm So Nos. of Bars = 4.77 Nos
Spacing = 209 mm 6. DESIGN OF GRA TI NGS L ayout of Gr atings :
Steel of Fy 275.0 Mpa shall be used for gratings. Main bar : 50X6 Flat Spacing of main bar : 30 mm c/c Secondary bar dia. = 12 mm
Say 200mm
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station Spacing of secondary bar : Thickness of gravel paving = Unit weight of gravel = Max span of main bar =
100 mm c/c 225 mm 16.00 kN/cum 1.698 m
6.1 Design of main bar : Self weight of grating : 0.56 kN/sqm Self weight of gravel : 3.60 kN/sqm Assumed live load : 2.00 kN/sqm Total load per unit area = 6.16 kN/sqm Uniform Distributed Load per main bar = 0.185 kN/m
Check for bending stress : 2
Max bending moment = 0.185*1.698 /8 = 0.067kN.m 2
Zxx of main bar = 6*50 /6 = 2500 mm3 Max bending stress = 0.067*10^6/2500 = 26.64 Mpa Allowable bending stress = 0.6*Fy = 0.6*275 = 165.00 Mpa
; So OK.
Check for shear stress : Max shear force = 0.157 kN Max shear stress = 0.52 Mpa Allowable Shear stress = 0.346*Fy = 0.346*275 = 95.15 Mpa
; So OK.
Check for max deflection : Ixx of main bar = 6*50^3/12 = 62500 mm4 Modulus of elasticity of steel = 200000 Mpa 4
= = . Allowable Maximum deflection = l/325 = 5.22 mm
; So OK.
6.2 Design of grating supporting channel : Max span of channel = 2.505 m Load from grating per channel = 6.16*2.505 = 15.431 kN/m Max bending moment , M = 12.104kN.m Max end shear, V = 19.327 kN Provide : ISMC 200
Check for bending stress : Total depth, D = 200 mm Sectional Area, A = 2828 mm2 r y = 22.3 mm Flange thickness, T = 10.40 mm Web thickness, tw = 6.1 mm Zxx = 182500 mm3 Ixx = 18251000 mm4 Leff / r yy = 2700/22.3= 112.33 3
When
703 X10 Cb
Fy
≤
l ≤ r
3
3516 X10 Cb
Fy
2 ⎡ ⎤ Fy l 2 ⎢ r ⎥ F ≤ 0.60F Fb = ⎢ − y y 3 3 10550 X 10 Cb ⎥ ⎢ ⎥ ⎣ ⎦ 2 Where C b = 1.75 + 1 .05 * (M 1 / M 2) + 0.3(M 1 / M 2)
(
)
Consider ends of channel are not to carry any moment so 2nd and 3rd term of the above equation can be ignored. So C b = 1.75 Bending Stress = M/Z = 12.1*10^6/182500 = 66.32 Mpa ∴ Fb = 0.535*275 = 147.13 Mpa > 66.32 Mpa ; So OK.
Check for shear stress : Shear stress = V/A = 19.327*1000/2828 = 6.83 Mpa Allowable Shear stress = 0.346*Fy = 0.346*275 = 95.15 Mpa
> 6.83 Mpa ; So OK.
MT H J GAARD A/S - L INDPRO A/S J V Design of Transformer Foundation ; J oydevpur 132/33kV Sub-station Check for max deflection : 4
Max central deflection = 5wl /384EI = 2.17 mm Allowable Max. deflection = l/325 =2825/325 = 7.71 mm
; So OK.
MT H JGAARD A/S - LINDPRO A/S JV Design of Transformer Foundation ; Joydevpur 132/33kV Sub-station Contents
Page No.
1. General
03
1.1 Considerations :
03
1.2 Soil Data:
03
1.3 Material Properties :
03
2. Design Data Foundation Geometry :
03
3. Load Calculation :
04
3.1 Wind load calculation - as per BNBC
04
3.2 Seismic load calculation - as per BNBC
04
4. Soil Stability Check
04
4.1 Check for Soil Bearing Capacity :
04
4.2 Check for Settlement :
05
5. Structural Design :
05
5.1 Design of Pit Wall :
05
5.1.1 - Reinforcement Calculation :
06
5.2 Design of Transformer Supporting Pedestal :
06
5.3. Design of Base Slab
07
5.3.1 Check for Punching of the Base :
07
5.3.2 Bottom Reinforcement Along Long Direction :
07
5.3.3 Bottom Reinforcement Along Short Direction :
08
5.3.4 Top Reinforcement Calculation along both direction :
09
6. Design of Grating :
09
6.1 Design of main bar :
10
6.2 Design of grating supporting channel :
10
Giasuddin / BEL
Date : 19 Nov '05
MT H JGAARD A/S - LINDPRO A/S JV Design of Transformer Foundation ; Joydevpur 132/33kV Sub-station Contents
Page No.
1. General
03
1.1 Considerations :
03
1.2 Soil Data:
03
1.3 Material Properties :
03
2. Design Data Foundation Geometry :
03
3. Load Calculation :
04
3.1 Wind load calculation - as per BNBC
04
3.2 Seismic load calculation - as per BNBC
04
4. Soil Stability Check
04
4.1 Check for Soil Bearing Capacity :
04
4.2 Check for Settlement :
05
5. Structural Design :
05
5.1 Design of Pit Wall :
05
5.1.1 - Reinforcement Calculation :
06
5.2 Design of Transformer Supporting Pedestal :
06
5.3. Design of Base Slab
07
5.3.1 Check for Punching of the Base :
07
5.3.2 Bottom Reinforcement Along Long Direction :
07
5.3.3 Bottom Reinforcement Along Short Direction :
08
5.3.4 Top Reinforcement Calculation along both direction :
09
6. Design of Grating :
09
6.1 Design of main bar :
10
6.2 Design of grating supporting channel :
10
Giasuddin / BEL
Date : 19 Nov '05
