counterfort-17m

Project

:

Title

: Design of Counterfort Type retainings walls

Revision

: R0 R0

Date

: 03 03.12.2015

Design report for Counterfort type retaining walls for approaches of bridges/ROB

Design Code

Project: Subject

Design of retaining wall (counter fort type)

RE-001

Date Revision

Introduction This document pertains to the design of c o u n t e r f o r t t y p e r e t ai n i n g w a l l s f o r a p p o a c h e s o f b r i d g e s for following heights 

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 Grade of Steel Cover to Reinforcement

M25 Fe 500

Foundations Walls

75 mm 50mm

Counter forts

40mm

Friction coefficient considered for design

0.5

 Angle of Internal friction for back fill

30 deg

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision

Basic Input

Remarks

Height of wall above Ground level

17 m

Depth of foundation

2 m ( FNL of abutment)

Total height of retaining wall , H

19 m

Concret M25 (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

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

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

 Angle of Internal friction of Back fill material

f

Unit weight of back fill material Grade of concrete Unit weight of concrete Grade of steel

240

3m

Clear spacing counterforts

Equivalent height for LL surcharge pressure

sst

1 8. 4 m 30.00 deg. 1.2 m 2 t/cum M25 2.5 t/cum Fe 500

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision

0.5 7

17

Df= 2

5

8

9

0 1 1 0.5

4.5

Kah calculation

0.6 Earth press

surcharge pressure

9

(ie horizontal c omponenet of active earth pressure)

angle of inclination of wall with horizontal

a

90.00 deg

angle of inclination of top surface of soil - horz

b

0.00 deg

1.57 rad 0.00

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

angle of wall friction

Date Revision 20.00 deg

d

Kh

0.280

Kv

0.102

Clear cover to reinforcement (walls)  

RE-001

0.35 rad as per columb's theory

50 mm 75 mm

f ootings

Check for stability (under Normal case) S.No Item description 1 Self weight of structure I Footing  14* 600/1000* 2.5

7

147.000

2

 500/1000*( 0)/1000* 2.5

0.000

 4.5+(0.5* 500/1000)

4.75

0.000

0.5*9.00* 0/1000* 2.5

0.000 0.000

 14-0.66*9.00 0.66* 4.5

8.06 2.97

0.000 0.000 0.000

23.00

 4.5+0.5* 500/1000

4.75

109.250

5

0.000

5 2

Mom(t.m)

Lever arm wrt toe

1 3 4 wall

II

Load(t)

6 Soil over  

21

0.5* 0* 4.5/1000* 2.5

( 500/1000)*( 19-( 600/1000))* 2.5 0.5*( 19-( 600/1000))*( 500500)/1000* 2.5

 14/2

0.00

 4.5+( 500/1000)+(0.33*( 500- 500)/1000)

0.00

 4.5+( 500/1000)+(0.66*( 500- 500)/1000)

wall (7)

0.5*( 19-( 600/1000))*( 500500)/1000* 2

heel (8)

 18.4*9.00* 2

toe

 4.5* 0* 2

0.00

0.5* 4.5

traingular component of earth fill over retaining wall(10)

0.5*(9.00)*(19.00- 19)* 2

0.00

0.666*9.00+ 500/1000+ 4.5

5 Vertical component of Backfill

0.5*0.102* 2*19.00^2

(9)

331.20

36.76

5

0.000

9.5

3146.400

2.25

0.000

10.994

0.000

5.00

183.778

Stabilising moment

3586.428

 14-0.5*9.00

 4.5+( 500/1000+0.5*( 500- 500)/1000)

V Horzontal loads Horizontal component (active) 0.5*0.280* 2*19.00^2

101.041

LL surcharge

12.763 113.804

1.2* 2*0.280* 19

0..42*19.00

7.98 9.5

806.307 121.249 927.556 t.m

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

Total Active Earth Pressure behind Retaining wall

RE-001

Date Revision

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' B/2-x'

(3586.428-927.556)/411.96

Pmax (P1) Net SBC at founding level Pmin (P2)

411.96/ 14*(1+6*0.546/ 14)

 14/2-6.454

36.31- 2* 2 411.96/ 14*(1-6*0.546/ 14)

6.454 m 0.546 m

b/6 = 2.33

36.31 t/sq.m 32.31 t/sq.m 22.543 t/sq.m

Design of foundation: Design of Toe slab: Earth pressure from bottom at tip, p1

36.31

Earth pressure at face of wall, P3

22.543+(( 14- 4.5)/ 14*(36.31-22.543))

31.88 t/sq.m

(36.31+31.88)/2

34.10 t/sq.m

 Average pressure Soil + self weight form top

( 600+ 0+ 600)/2000* 2.5+( 2-( 600+ 0+ 600)/2000)* 2

Net Pressur intensity

34.10- 4.3

36.31 t/sq.m

4.3 t/sq.m 29.80 t/sq.m

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision y

1.50 1.50 x

4.5 4.30

Load from top

31.88

Max. pr distr.

32.01

27.58

Net . Pr. Dist

27.58

UDL

Net Avg. Pr dist

36.31

Traingular  4.42 a/b

Moment Coefficients for UD L (slab fixing along three edges , )

Mx +ve

Mx +ve Mx -ve My +ve My -ve

Min depth as per balanced section

As per Engineering Monograph no 27 UDL

Mx-ve My +ve My-ve Rectr distribution Moments

= 0.32

0.034 0.018 0.021 0.006 Traingular distribution

Train'ler  

0.016 0.008 0.015 0.005

0.034*27.58*(4.5)^2+0.016*4.42*(4.5)^2

20.56

t.m

0.018*27.58*(4.5)^2+0.008*4.42*(4.5)^2

10.64

t.m

0.021*27.58*(4.5)^2+0.015*4.42*(4.5)^2

13.13

t.m

3.69

t.m

457.6

mm

0.006*27.58*(4.5)^2+0.005*4.42*(4.5)^2 SQRT(20.56*10000000/(1000*0.982))

>

517

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I Steel

RE-001

Date Revision

Ast x +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

720.00

sq.mm

min Ast

(0.0012*1000*( 600+ 0))

Check for Shear  UDL Max reaction

Tr ' ler   21

0.166*27.58*4.5+0.01*4.42*4.5

Tv

t at deff 

0.4024

N/sq.mm

0.3800

N/sq.mm

Vus/d

0.2240

kN/cm

Provide shear links

Provide Y8 shear links

Tc

for pt

=

0.49

Provide  Y20-125 Provide  Y16-150 Provide  Y16-125 Provide  Y12-150

(bot) (top) (bot) (top)

per meter 

x-dir  x-dir  Y-dir  Y-dir 

Design of heel slab : Earth pressure from bottom at tip Earth pressure at face of wall

22.54 t/sq.m 22.543+((9.00)/ 14*(36.31-22.543))

31.39 t/sq.m

(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

 Average pressure

-7.65 t/sq.m Y

1.50

1.50

X

9.0

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision 34.62

Load from top

22.54

Max. pr distr.

31.39 -12.08 -3.23 Net . Pr. Dist

-3.23

UDL

Net Avg. Pr dist

Traingular  -8.85

a/b

= 0.16

As per Engineering Monograph

Moment Coefficients for UD L

UDL

(slab fixing along three edges , )

Moments

Min depth as per balanced section Steel

Train'ler  no 27

Mx +ve

0.009

0.008

Mx-ve

0.005

0.004

My +ve

0.006

0.007

My-ve

0.001

0.002

-7.76

t.m

-3.97

t.m

-6.44

t.m

-1.65

t.m

281.1

mm

Ast x +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

Mx +ve

0.009*-3.23*(9.00)^2+0.008*-8.85*(9.00)^2

Mx -ve

0.005*-3.23*(9.00)^2+0.004*-8.85*(9.00)^2

My +ve

0.006*-3.23*(9.00)^2+0.007*-8.85*(9.00)^2

My -ve

0.001*-3.23*(9.00)^2+0.002*-8.85*(9.00)^2 SQRT(ABS(-7.76)*10000000/(1000*0.982))

>

517

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision

 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

720.00

sq.mm

(0.0012*1000*( 600+ 0))

Check for Shear  UDL Max reaction

Tr ' ler   -11

0.32*-3.23*9.0+0.0189*-8.85*9.0

Tv Tc

for pt

=

0.26

Vus/d Provide shear links

-0.2089

N/sq.mm

0.2650

N/sq.mm

-4.7395

kN/cm

per meter 

No shear is required Provide Provide Provide Provide

 Y16-150  Y12-100  Y16-150  Y10-125

(top) (bot) (top) (bot)

x-dir  x-dir  Y-dir  Y-dir 

Wall design : Height of wall Earth pressure Due to LL surcharge

 19-( 0+ 600)/1000 (18.40* 2*0.280) ( 2* 1.2*0.280)

18.40 m 10.300 t/sq.m 0.672 t/sq.m

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision

Y

1.50

1.50

a= b=

1.500 18.40 a/b = 0.082

18.40

 

X

3 .0 0 m

Moment Coefficients for UDL and Trainguler  (slab fixing along three edges , )

Moments

Mx +ve Mx-ve My +ve My-ve

Mx +ve Mx -ve My +ve My -ve

Min depth as per balanced section Steel

Ast x +ve  Ast x - ve  Ast y +ve  Ast y - ve min Ast

UDL(LL) 0.0052 0.0027 0.0033 0.0007

0.672 UDL(LL)

10.300 t/sq.m D'ler(Earth Pressure) Dist.

D'ler(EP)

As per Engineering Monograph no 27

0.0036 0.0019 0.0030 0.0005

0.0052*0.67*(18.40)^2 + 0.0036*10.30*(18.40)^2 0.0027*0.67*(18.40)^2 + 0.0019*10.30*(18.40)^2 0.0033*0.67*(18.40)^2 + 0.0030*10.30*(18.40)^2 0.0007*0.67*(18.40)^2 + 0.0005*10.30*(18.40)^2 SQRT(13.74*10000000/(1000*0.914))

13.74 7.24 11.21 1.90 380.3

t.m t.m t.m t.m mm

(13.74*10000000/(230*0.904*((2.00-0.10-8))) (7.24*10000000/(230*0.904*((2.00-0.10-8))) (11.21*10000000/(230*0.904*((2.00-0.10-8))) (1.90*10000000/(230*0.904*((2.00-0.10-8))) 0.0012*1000*2.0

1501.7 791.5 1225.7 208.0 750.00

sq.mm sq.mm sq.mm sq.mm sq.mm

<

417

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date Revision

Provide  Y16-125

Earth face

Provide  Y12-100

away from E/F x-dir 

x-dir 

Provide  Y16-125

Earth face

Provide  Y10-150

away from E/F y-dir 

y-dir 

Counter fort Design on Heel side Size at bottom

500.0*9,500.0

Maximum BM in One counterfort

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))

Depth required for balanced section

1913.98 t.m 6246.7 mm Provided 9500

1913.98*10000000/(0.914*240*(9500-91-90))

 Ast rerquired

mm

9362.9 Provide 14-Y32

(0.5*0.280* 2*( 19- 600*0.001)^2*3.00+ 1.2* 2*0.280*3.00*( 19- 600*0.001))

Shear force

321.4*10000/( 500*(9500-85))

321.4 t

.

tv

% of steel

Pt

0.203 %

Shear strength

tc

0.250

Vus/d

9648

0.7 N/sq.mm

<

tv

2.163 Hence Provide Y10-2L-150as Shear reinforcement

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I

RE-001

Date 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

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)

600.92 t.m

SQRT(600.92*10000000/( 500* .981))

Depth required for balanced section

3500.2 mm Provided 6365 4366.3

600.92*10000000/(0.914*240*(6365-91))

 Ast rerquired

Provide 6-Y32 (0.280* 2*(( 19- 600*0.001)*0.67)^2*3.00+ 1.2* 2*0.280*3.00*( 19600*0.001)*0.67)

Shear force .

tv

4824

280.1 t

280.1*10000/( 500*(6365-85))

0.9 N/sq.mm

Pt Shear strength

mm

0.152 % tc

0.230

Vus/d

<

tv

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 Maximum BM in One counterfort

500.0*3,163.5

Depth required for balanced section

SQRT(83.29*10000000/( 500* .981))

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)

83.29 t.m 1303.1 mm Provided 3164

 Ast rerquired

83.29*10000000/(0.914*240*(3164-91))

mm

1235.8 Provide 4-Y32

3216

Sheet no:

Project: Design Code

Subject

Design of retaining wall (counter fort type) _Case-I (0.280* 2*(( 19- 600*0.001)*0.333)^2*3.00+ 1.2* 2*0.280*3.00*( 19600*0.001)*0.333)

Shear force .

75.4*10000/( 500*(3164-85))

tv

Pt Shear strength

RE-001

Date Revision 75.4 t 0.5 N/sq.mm 0.203 %

tc

0.230

Vus/d

<

tv

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

Net Pressur at bottom

29.795 t/sq.m

Maximum BM in One counterfort ( spaced at 3.0m c/c)

29.795*3*4.5^2/2

Depth required for balanced section

SQRT(905.04*10000000/( 500* .981))

905.04 t.m 4295.50 mm Provide 3500

905.04*10000000/(0.914*240*(3500-91))

 Ast rerquired

=

mm

12102.69 sq.mm Provide 8-Y32

29.795* 4.5*2.5/3.5

Shear force Shear stress

Shear strength

95.77 t

tv 95.77*10000/( 500*(3500-85))

0.56 N/sq.mm

Pt

0.69 %

tc

0.23 N/sq.mm

Vus/d

1.654 kn/cm Hence Provide Y10-2L-150 as Shear reinforcement

Sheet no: