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Design report for Counterfort type retaining walls for approaches of bridges/ROB
Design report for Counterfort type retaining walls for approaches of bridges/ROB
Revision
Introduction
Height
above
GL
17 m
Depth of foundation
2 m
The net safe bearing capacity considered for the design is 33t/sq.m.
Material Properties
Grade of concrete
M25
Grade
of
Steel
Fe
500
Cover to Reinforcement
Foundations
75 mm
Walls
50mm
Counter
forts
40mm
Friction coefficient considered for design
0.5
This document pertains to the design of
c o unt er for t t y p e r et ai n i ng w a l l s fo r a ppo ac h es of br i dg es
fo r f ol l ow i ng h ei g hts
Revision
Basic Input Remarks
Height of wall above Ground level 17 m
Depth of foundation 2 m ( FNL of abutment) Concret M25
Total height of retaining wall , H 19 m (RCC)
19.00
Top width of wall wt 500 mm Steel Fe500
bottom width of wall wb 500 mm Q 0.981
thickness of footing at edge t1 600 mm J 0.914
t2 0 mm sst 240
Width of toe slab tw 4.5 m
width of heel slab hw 9.00 m
Total width of foundation 4.5+9.00+ 500/1000 14 m
Clear spacing counterforts
3 m
width of counterfort 500
mm
c/c spacing of counterforts 3.00 m
Average depth of soil fill over toe slab 0 m
Average depth of soil fill over heel slab 19.00-0.60 1 8. 4 m
Angle of Internal friction of Back fill material f 30.00 deg.
Equivalent height for LL surcharge pressure 1.2 m
Unit weight of back fill material 2 t/cum
Grade of concrete M25
Unit weight of concrete 2.5 t/cum
Design Code RE-001
Design of retaining wall (counter fort type) _Case-I Date
Revision Project: Subject 0.5 7 17 8 Df= 2 9 0 1 0.6
Earth press surcharge pressure
4.5 9
Kah calculation (ie horizontal c omponenet of active earth pressure)
angle of inclination of wall with horizontal a 90.00 deg 1.57 rad
angle of inclination of top surface of soil - horz b 0.00 deg 0.00
0.5 1 5
Revision
angle of wall friction d 20.00 deg 0.35 rad
Kh 0.280
Kv 0.102
Clear cover to reinforcement (walls) 50 mm
f ootings 75 mm
Check for stability (under Normal case)
S.No Load(t) Mom(t.m)
1 Self weight of structure
I Footing 1 21 14/2 7 147.000 2 0.000 4.5+(0.5* 500/1000) 4.75 0.000 3 0.000 14-0.66*9.00 8.06 0.000 4 0.000 0.66* 4.5 2.97 0.000 II wall 0.000 5 23.00 4.5+0.5* 500/1000 4.75 109.250 6 0.00 4.5+( 500/1000)+(0.33*( 500- 500)/1000) 5 0.000 2 Soil over wall (7) 0.00 4.5+( 500/1000)+(0.66*( 500- 500)/1000) 5 0.000 heel (8) 331.20 14-0.5*9.00 9.5 3146.400 toe (9) 0.00 0.5* 4.5 2.25 0.000 0.5*(9.00)*(19.00- 19)* 2 0.00 0.666*9.00+ 500/1000+ 4.5 10.994 0.000 36.76 4.5+( 500/1000+0.5*( 500- 500)/1000) 5.00 183.778 3586.428 Horzontal loads 0.5*0.280* 2*19.00^2 101.041 0..42*19.00 7.98 806.307 LLsurcharge 1.2*2*0.280*19 12.763 9.5 121.249 113.804 927.556 t.m
Item description Lever arm wrt toe
14* 600/1000* 2.5 500/1000*( 0)/1000* 2.5
as per columb's theory
0.5*9.00* 0/1000* 2.5 0.5* 0* 4.5/1000* 2.5 ( 500/1000)*( 19-( 600/1000))* 2.5 0.5*( 19-( 600/1000))*( 500-500)/1000* 2.5 0.5*( 19-( 600/1000))*( 500-500)/1000* 2 18.4*9.00* 2 4.5* 0* 2
traingular component of earth fill over retaining wall(10) 5 Vertical component of
Backfill 0.5*0.102* 2*19.00^2
Stabilising moment
Horizontal component (active)
Design Code RE-001
Design of retaining wall (counter fort type) _Case-I Date
Revision Project:
Subject
Total Active Earth Pressure behind Retaining wall 113.80
m
F.S against Overturning (S M / S Mo ) ROUNDUP(3586.428/927.556,1) 3.90 >2.0 Hence ok
F.S against sliding ( S V * m / S H) (411.96*0.5)/113.80 1.81 >1.5 Hence ok
X' (3586.428-927.556)/411.96 6.454 m b/6 =
B/2-x' 14/2-6.454 0.546 m 2.33
Pmax (P1) 411.96/ 14*(1+6*0.546/ 14) 36.31 t/sq.m
Net SBC at founding level 36.31- 2* 2 32.31 t/sq.m
Pmin (P2) 411.96/ 14*(1-6*0.546/ 14) 22.543 t/sq.m
Design of foundation: Design of Toe slab:
Earth pressure from bottom at tip, p1 36.31 36.31 t/sq.m
Earth pressure at face of wall, P3 22.543+(( 14- 4.5)/ 14*(36.31-22.543)) 31.88 t/sq.m
Average pressure (36.31+31.88)/2 34.10 t/sq.m
Soil + self weight form top ( 600+ 0+ 600)/2000* 2.5+( 2-( 600+ 0+ 600)/2000)* 2 4.3 t/sq.m
NetPressurintensity 34.10-4.3 29.80 t/sq.m
Revision y
1.50 1.50
x 4.5
4.30 Load from top
31.88 Max. pr distr.
36.31
32.01 27.58 Net . Pr. Dist
27.58 UDL Net Avg. Pr dist
Traingular
4.42
a/b = 0.32
Moment Coefficients for UD L UDL Train'ler
(slab fixing along three edges , ) Mx +ve 0.034 0.016
Mx-ve 0.018 0.008
My +ve 0.021 0.015
My-ve 0.006 0.005
Rectr distribution Traingular distribution
Moments Mx +ve 0.034*27.58*(4.5)^2+0.016*4.42*(4.5)^2 20.56 t.m
Mx -ve 0.018*27.58*(4.5)^2+0.008*4.42*(4.5)^2 10.64 t.m
My +ve 0.021*27.58*(4.5)^2+0.015*4.42*(4.5)^2 13.13 t.m
My -ve 0.006*27.58*(4.5)^2+0.005*4.42*(4.5)^2 3.69 t.m
Min depth as per balanced section SQRT(20.56*10000000/(1000*0.982)) 457.6 mm > 517
Design Code RE-001
Design of retaining wall (counter fort type) _Case-I Date
Revision Project:
Subject
Steel Astx+ve (20.56*10000000/(240*0.914*(( 600+ 0)- 75-8))) 1812.88 sq.mm top
Ast x - ve (10.64*10000000/(240*0.914*(( 600+ 0)- 75-8))) 938.30 sq.mm bot
Ast y +ve (13.13*10000000/(240*0.914*(( 600+ 0)- 75-8))) 1158.02 sq.mm top
Ast y - ve (3.69*10000000/(240*0.914*(( 600+ 0)- 75-8))) 325.16 sq.mm bot
min Ast (0.0012*1000*( 600+ 0)) 720.00 sq.mm
Check for Shear
UDL Tr ' ler
Max reaction 0.166*27.58*4.5+0.01*4.42*4.5 21 t at deff
Tv 0.4024 N/sq.mm
Tc for pt = 0.49 0.3800 N/sq.mm
Vus/d 0.2240 kN/cm per meter
Provide shear links Provide Y8 shear links
Provide Y20-125 (bot) x-dir
Provide Y16-150 (top) x-dir
Provide Y16-125 (bot) Y-dir
Provide Y12-150 (top) Y-dir
Design of heel slab :
Earthpressurefrombottomattip 22.54 t/sq.m
Earth pressure at face of wall 22.543+((9.00)/ 14*(36.31-22.543)) 31.39 t/sq.m
Average pressure (22.54+31.39)/2 26.97 t/sq.m
Soil + self weight form top ( 600+ 0+ 600)/2000* 2.5+( 19-(( 600+ 0+ 600)/1000)*0.5)*1.8 34.62 t/sq.m
Net Pressur intensity -34.62+26.97 -7.65 t/sq.m
Y
1.50
1.50
X 9.0
Revision
34.62 Load from top
22.54 Max. pr distr. 31.39
-12.08 -3.23
Net . Pr. Dist
-3.23 UDL NetAvg.Prdist
Traingular -8.85
a/b = 0.16
Moment Coefficients for UD L UDL Train'ler
(slab fixing along three edges , ) Mx +ve 0.009 0.008
Mx-ve 0.005 0.004 My +ve 0.006 0.007 My-ve 0.001 0.002 Moments Mx +ve 0.009*-3.23*(9.00)^2+0.008*-8.85*(9.00)^2 -7.76 t.m Mx -ve 0.005*-3.23*(9.00)^2+0.004*-8.85*(9.00)^2 -3.97 t.m My +ve 0.006*-3.23*(9.00)^2+0.007*-8.85*(9.00)^2 -6.44 t.m My -ve 0.001*-3.23*(9.00)^2+0.002*-8.85*(9.00)^2 -1.65 t.m
Min depth as per balanced section SQRT(ABS(-7.76)*10000000/(1000*0.982)) 281.1 mm > 517
Steel Astx+ve (ABS(-7.76)*10000000/(230*0.914*(( 600+ 0)- 75-8))) 714.14 sq.mm top
Ast x - ve (ABS(-3.97)*10000000/(230*0.914*(( 600+ 0)- 75-8))) 364.88 sq.mm bot
As per Engineering Monograph no 27
Design Code RE-001
Design of retaining wall (counter fort type) _Case-I Date
Revision Project:
Subject
Ast y +ve (ABS(-6.44)*10000000/(230*0.914*(( 600+ 0)- 75-8))) 592.48 sq.mm top
Ast y - ve (ABS(-1.65)*10000000/(230*0.914*(( 600+ 0)- 75-8))) 151.79 sq.mm bot
min Ast (0.0012*1000*( 600+ 0)) 720.00 sq.mm
Check for Shear
UDL Tr ' ler
Max reaction 0.32*-3.23*9.0+0.0189*-8.85*9.0 -11
Tv -0.2089 N/sq.mm
Tc for pt = 0.26 0.2650 N/sq.mm
Vus/d -4.7395 kN/cm per meter
Provide shear links No shear is required
Provide Y16-150 (top) x-dir
Provide Y12-100 (bot) x-dir
Provide Y16-150 (top) Y-dir
Provide Y10-125 (bot) Y-dir
Wall design :
Height of wall 19-( 0+ 600)/1000 18.40 m
Earth pressure (18.40* 2*0.280) 10.300 t/sq.m
Due to LL surcharge ( 2* 1.2*0.280) 0.672 t/sq.m
Revision Y 1.50 1.50 a= 1.500 b = 18.40 a/b = 0.082 18.40 X 0.672 10.300 t/sq.m
3 .0 0 m UDL(LL) D'ler(Earth Pressure) Dist.
Moment Coefficients for UDL and Trainguler UDL(LL) D'ler(EP)
(slab fixing along three edges , ) Mx +ve 0.0052 0.0036
Mx-ve 0.0027 0.0019 My +ve 0.0033 0.0030 My-ve 0.0007 0.0005 Moments Mx +ve 0.0052*0.67*(18.40)^2 + 0.0036*10.30*(18.40)^2 13.74 t.m Mx -ve 0.0027*0.67*(18.40)^2 + 0.0019*10.30*(18.40)^2 7.24 t.m My +ve 0.0033*0.67*(18.40)^2 + 0.0030*10.30*(18.40)^2 11.21 t.m My -ve 0.0007*0.67*(18.40)^2 + 0.0005*10.30*(18.40)^2 1.90 t.m
Min depth as per balanced section SQRT(13.74*10000000/(1000*0.914)) 380.3 mm < 417
Steel Astx+ve (13.74*10000000/(230*0.904*((2.00-0.10-8))) 1501.7 sq.mm
Ast x - ve (7.24*10000000/(230*0.904*((2.00-0.10-8))) 791.5 sq.mm
Ast y +ve (11.21*10000000/(230*0.904*((2.00-0.10-8))) 1225.7 sq.mm
Ast y - ve (1.90*10000000/(230*0.904*((2.00-0.10-8))) 208.0 sq.mm
min Ast 0.0012*1000*2.0 750.00 sq.mm
As per Engineering Monograph no 27
Design Code RE-001
Design of retaining wall (counter fort type) _Case-I Date
Revision Project:
Subject
Provide Y16-125 Earth face x-dir
Provide Y12-100 away from E/F x-dir
Provide Y16-125 Earth face y-dir
Provide Y10-150 away from E/F y-dir
Counter fort Design on Heel side
Size at bottom 500.0*9,500.0
Maximum BM in One counterfort
1913.98 t.m
Depth required for balanced section 6246.7 mm
Provided 9500 mm Ast rerquired 9362.9 Provide 14-Y32 9648 Shear force 321.4 t . tv 0.7 N/sq.mm % of steel Pt 0.203 % Shear strength tc 0.250 < tv Vus/d 2.163
Hence Provide Y10-2L-150as Shear reinforcement
0.5*(0.280* 2*( 19- 600*0.001)*3.00*0.3333*( 19- 600*0.001)^2+ 1.2* 2*0.280*3.00*0.5*( 19- 600*0.001)^2) SQRT(1913.98*10000000/( 500* .981)) 1913.98*10000000/(0.914*240*(9500-91-90)) (0.5*0.280* 2*( 19- 600*0.001)^2*3.00+ 1.2* 2*0.280*3.00*( 19- 600*0.001)) 321.4*10000/( 500*(9500-85)) Sheet no:
Revision Curtailment
Counter fort Design on Heel side
Size at section where the reinf curtailed ( 500.0*6,365.0
Maximum BM in One counterfort
600.92 t.m
Depth required for balanced section 3500.2 mm
Provided 6365 mm Ast rerquired 4366.3 Provide 6-Y32 4824 Shear force 280.1 t . tv 0.9 N/sq.mm Pt 0.152 % Shear strength tc 0.230 < tv Vus/d 3.310 kn/cm
Hence Provide Y10-2L-150 as Shear reinforcement Counter fort Design on Heel side
Size at section where the reinf curtailed 500.0*3,163.5
Maximum BM in One counterfort
83.29 t.m
Depth required for balanced section 1303.1 mm
Provided 3164 mm Ast rerquired 1235.8 Provide 4-Y32 3216 0.5*(0.280* 2*( 19- 600*0.001)*0.67*3.00*0.3333*(( 19- 600*0.001)*0.67)^2+ 1.2* 2*0.280*3.00*0.5*(( 19- 600*0.001)*0.67)^2) SQRT(600.92*10000000/( 500* .981)) 600.92*10000000/(0.914*240*(6365-91)) (0.280* 2*(( 600*0.001)*0.67)^2*3.00+ 1.2* 2*0.280*3.00*( 19-600*0.001)*0.67) 280.1*10000/( 500*(6365-85)) 0.5*(0.280* 2*( 19- 600*0.001)*0.333*3.00*0.3333*(( 19- 600*0.001)*0.333)^2+ 1.2* 2*0.280*3.00*0.5*(( 19- 600*0.001)*0.333)^2) SQRT(83.29*10000000/( 500* .981)) 83.29*10000000/(0.914*240*(3164-91))
Design Code RE-001
Design of retaining wall (counter fort type) _Case-I Date
Revision Project: Subject Shear force 75.4 t . tv 0.5 N/sq.mm Pt 0.203 % Shear strength tc 0.230 < tv Vus/d 1.299 kn/cm
Hence Provide Y10-2L-125 as Shear reinforcement Counter fort Design on TOE side
Size at bottom 500.0*3,500.0
AVG Base pressure at bottom on toe side 34.095 t/sq.m
NetPressuratbottom 29.795 t/sq.m
Maximum BM in One counterfort ( spaced at 3.0m c/c) 905.04 t.m =
Depthrequiredforbalancedsection 4295.50 mm
Provide 3500 mm Ast rerquired 12102.69 sq.mm Provide 8-Y32 Shearforce 95.77 t Shear stress tv 0.56 N/sq.mm Pt 0.69 % Shear strength tc 0.23 N/sq.mm Vus/d 1.654 kn/cm
Hence Provide Y10-2L-150 as Shear reinforcement (0.280* 2*(( 600*0.001)*0.333)^2*3.00+ 1.2* 2*0.280*3.00*( 19-600*0.001)*0.333) 75.4*10000/( 500*(3164-85)) 29.795*3*4.5^2/2 SQRT(905.04*10000000/( 500* .981)) 905.04*10000000/(0.914*240*(3500-91)) 29.795* 4.5*2.5/3.5 95.77*10000/( 500*(3500-85)) Sheet no:
