Bridge Pier

7/29/2019 Bridge Pier

1/18

Centre to centre of pier 20.00 m

RBL 551.00 m

Bed level of canal 570.00 m

Hard rock level; 549.50 m

Thickness of pier at top 1.20 m

Sode slope of the pier 12V:1H

Base width 2.53 mWidth of the trough 5.55 m

Depth of flow of water 4.80 m (including surge)

Thickness of bed slab of trough 0.75 m

Ground level 560.00 m

Top of deck slab of catwalk 575.65 m

Thickness of bearing 0.50 m

Thickness of bed block/pier cap 0.75 m

Assume thickness of well cap= 1.25 m

Size of the base 2.53m X 5.00m

Bottom of deck slab 569.25 m

Top of bed block level 568.75 m

Bottom of bed block 568.00 mHeight of pier 8.00 m

Horizontal seismic coefficient 0.08 g

Deepest bed level 549.50 m

Thickness of steining 0.70 m

Pier length below corbel 5 m

DESIGN OF WELL CAP

1


2/18

2. TENTATIVE SECTION OF THE PIER

575.65m

V1=343.93t V1=343.93t

on each bearing

H=37.22T

1.20m

1 1

12 12

V2=191.446t

2.53m

560.00m

551.00m

V1=

D

h

.50m

2


3/18

5.00m Myy

2.53m

Mxx

+VE

+VE

+VE

3


4/18

3. EVALUATION OF FORCES:

a)Dead load of super structure

R.L.of section under consideration 560.00 m

SL.NO. DESCRIPTION OF LOAD NO. V(t) transition

I TROUGH PORTION

1 Weight of side beams 2 20.00 X 1.00 X 4.02 X 2.40 385.92

2 Weight of fillets 2 20.00 X 1.50 X 0.78 X 2.40 111.60

3 Weight of chamfers 2 20.00 X 0.65 X 1.21 X 2.40 75.63

4 weight of bed slab 1 20.00 X 2.50 X 0.45 X 2.40 54.00

5 Weight of bottom stiffener 6 0.50 X 4.00 X 0.65 X 2.40 18.72

6 Weight of top stiffener 6 0.50 X 5.50 X 0.75 X 2.40 29.70

7 Weight of top wedge/ext beam 6 20.00 X 0.40 X 0.35 X 2.40 40.32

8 Weight of side stiffener 6 0.70 X 2.19 X 0.50 X 2.40 11.06

9 Weight of cat walk beam 1 20.00 X 0.30 X 0.75 X 2.40 10.80

10 Weight of cat walk slab 1 20.00 X 0.90 X 0.20 X 2.40 8.64

11 Weight of water 1 20.00 X 5.50 X 4.80 X 1.00 528.00

12 weight of wearing coat 1 20.00 X 1.65 X 0.08 X 2.40 5.94

13 Weight of railing 6 20.00 X 0.25 X 0.25 X 0.79 5.89

14 Live Load 1 20.00 X 1.20 X 1.00 X 1.00 24.00

15 Add for unforseen loads 5% 65.51

TOTAL 1375.72 1500 125.25721

II PIER CAP

1 pier cap 1 1.80 X 8.00 X 0.75 X 2.40 25.92 15.967145

III PIER

1 weight of corbel portion 1 1.18 X 5.15 X 2.00 X 2.40 29.05 93.482906

2 Weight of pier 1 1.87 X 5.00 X 7.25 X 2.40 162.40 3500

217.37 432

III FOUNDATION

1 Well cap 1 3.14 X 8.41 X 1.25 X 2.40 79.26 216.22

79.26

Total with well cap 1672.35

Total without well cap 1593.09 2148.22

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5/18

Earthquake forces

H= 15.65

DESCRIPTION OF LOAD NO.

seismic

factor He Ve L1 L2 M1 M2

m m t m m t-m t-m

I TROUGH PORTION

1 Weight of side beams 1 11.65 0.09 34.47 17.24 11.65 2.50 401.62 43.09

2 Weight of fillets 2 16.20 0.12 13.86 6.93 16.20 2.50 224.57 17.33

3 Weight of chamfers 2 12.75 0.10 7.39 3.70 12.75 2.50 94.27 9.24

4 weight of bed slab 1 16.53 0.13 6.84 3.42 16.53 2.50 113.07 8.55

5 Weight of bottom stiffener 6 15.98 0.12 2.29 1.15 15.98 2.50 36.63 2.87

6 Weight of top stiffener 6 15.40 0.12 3.51 1.75 15.40 2.50 54.01 4.38

7 Weight of top wedge/ext beam 2 15.28 0.12 4.72 2.36 15.28 2.50 72.14 5.90

8 Weight of side stiffener 2 14.86 0.11 1.26 0.63 14.86 2.50 18.71 1.57

9 Weight of cat walk beam 1 15.43 0.12 1.28 0.64 15.43 2.40 19.70 1.53

10 Weight of cat walk slab 1 15.55 0.12 1.03 0.52 15.55 1.60 16.02 0.82

11 weight of wearing coat 1 15.55 0.12 0.71 0.35 15.55 2.50 11.01 0.89

12 Weight of railing 6 16.25 0.12 0.73 0.37 16.25 1.60 11.92 0.59

TOTAL 78.10 39.05 1073.68 96.77

II PIER

1 pier cap 1 16.03 0.12 3.18 1.59 16.03 1.6 51.04 2.55

2 weight of corbel portion 1 14.65 0.11 3.26 1.63 14.65 2.50 47.80 4.08

3 Weight of pier 1 10.03 0.08 12.48 6.24 10.03 2.50 125.15 15.60

0.00

18.93 9.47 223.99 22.23

III FOUNDATION

1 Well cap 1 0.50 0.00 0.30 0.15 0.50 2.50 0.15 0.38

0.30 0.15 0.1519407 0.38

total 97.339 48.670 1297.818 119.383

SL.NO. h

H

1.5 ah

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6/18

Y1= 2.45 ey= -1.186265 m

X1= 26.67 ex= -24.16586 m

HYDRODYNAMIC FORCES (trough)

He

Horizontal hydrodynamic force=He=0.726pe y

Moment about C.G=Me=0.299pey2

y [m] 4.80

h[m] 12.40

i Dueto upstream water

a= 21.337 o

Cm= 0.570

Cs= 0.403

pe= 0.400 t/sq.m

He= 27.88 t

Me= 100% 55.12 t-m

-+

-=

h

y2

h

y

h

y2

h

y

2

CC m

s

h

y

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7/18

Dynamic force in the longitudinal direction in the trough

Discharge in the trough(max) 47.25 cumec

Cross sectional area of flow= 26.640 sq.m

Perimeter of the flow of water in the trough 15.150 m

Kinematic viscocity= 1.14E-06 sq.m/sec

Flow velocity 1.77 m/s

Reynolds No. 7500

Drag Coeffcient 0.123

Drag force 37.22 t

Hydraulic mean depth 1.758 m

Shear force due to water/m length= 1.758 kg

Total force 0.533 t

R.L. of application of force 578.050 mHeight above the bed block= 10.050 m

Increase in reaction due to drag force= 37.221 t

Force due to sliding friction:

Reaction sliding end when the loads are so placed as to produce maximum reaction on the other end

L.L reaction= 24.00 t

Impact factor 25.00%

Impact load 6.00 t

Impact load 6.00 t

Dead load reaction 41.27 t

Load due to water in flow direction force 37.22 t

84.49 t

Friction in sliding (Coeff of friction= 0.25 21.12 t

R.L. of point of application of force 568.00 m

7


8/18

Wind force

The inensity of wind pressure depends on the height of structure exposed to the

wind. Two cases are dealt for computing wind force

(a). When level of water in the river is at HFL

(b). When there is minimum water level

Average height of pier above GL= 8.00 m

Area of exposed structure 148.27 sq.m

Height of pier above GL= 10.00 m

Intensity of wind pressure 121.77 kg/sq.m

Area of exposed structure 148.27 sq.m

Add for catwalk area 30.00 sq.m

Total area= 178.27 sq.m

Total wind force on the structure= 21.71 t

l1 6.40 m

l2 3.60 m

y= 5.713 m

RL of point of application 565.71

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9/18

MOMENT OF INERTIA OF PIER AT BASE:

Area of the base

B= 2.533m

L= 5.000m

A = B x L = =12.67 m2

M.I. Of the foundation:

=6.77 m4

=26.39 m4

Coeff. Friction at the bearings= 0.90

12

3LB

Ixx=

-

12

3BL

I yy =-

LBX

X

Y

Y

1

4 3

2

9


10/18

SL.NO LOAD HX HyDIRECT

STRESSX

BENDING

STRESS

(fx)

BENDING

STRESS

(fy)

t t t t/sq.m m t/sq.m t/sq.m

1 DEAD LOAD 1593.09 125.77 negligible

-do- dry CONDITION 1065.09 84.09

5 FORCE DUE TO SLIDING FRICTION 21.12 8.00 31.60 0.00

6 WIND FORCE 21.71 16.21 0.00 33.34

13 EARTQUAKE FORCES -48.67 97.34 97.34 -3.84 as above 0.00 112.77

222.56

14 HYDRO DYNAMIC FORCES 27.88 10.31 5.22

DETAILS

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11/18

CASE V Hx Hy F/A Sfx Sfy f1 f2 f3

t t t t/sq.m t/sq.m t/sq.m t/sq.m t/sq.m t/sq.m

1 STATIC & DRY CONDITION 1065.091 21.707 84.086 0.000 -33.341 50.75 117.43 117.43

2 1593.091 21.707 21.123 125.770 0.000 -33.341 124.03 190.71 127.51

dirction of eq. along flow

4 CASE(1)+E.Q(NO. WIND FORCE) 1016.421 97.339 118.462 80.244 0.000 46.084 302.81 302.81 -142.32

5 CASE(2)+E.Q(NO. WIND LOAD) 1544.421 125.224 118.462 121.928 10.307 51.306 386.39 386.39 -142.54

dirction of eq along the bridge

6 CASE(1)+E.Q(NO. WIND FORCE) 1016.421 97.339 118.462 80.244 0.000 46.084 -32.52 193.01 226.35

7 CASE(2)+E.Q(NO. WIND LOAD) 1544.421 125.224 118.462 121.928 10.307 51.306 51.07 276.60 276.60

dirction of eq across thebridge

Min. stress -32.521 117.427 -142.539

Max. Stress 386.395 386.395 276.597

max Tension= -142.539 t/sq.m

Max. Compression= 386.395 t/sq.m

STATIC & WHEN THERE IS WATER (

IN TROUGH)

CONDITION

11


12/18

Design of well cap:

Diameter of well(internal) 4.40 m

External dia 5.80 m

Effective dia= Min of L+d or L+t 5.10 m

depth assumed 1.25 m

Intensity of loading= 95.985 t/sq.m

Assuming well cap to be partially fixed moment,

Moment at mid span= 78.018 t-m

Grade of concrete M 20

Permissible stress in steel 1900.00 kg/sq.cm

Permissiblebond stress= 8.00 kg/sq.cm

Permissible tensile strength in concrete= 20 kg/sq.cmWhether with Earthquake considered(Y/N)

Permissible compressive strength of concrete= 7 N/mm2

m= 13.3333

k= 0.3294

j= 0.8902

Q= 10.2634 bd2

Depth of well cap= 87.19 cm

Steel required at mid span & bottom of well cap (+ve moment)

Dia of the bar 25 mm

Area 4.91 sq.cm

Overall depth= 102.19 cmSay 125.00 cm

Effective depth= 117.50 cm

Area of steel= 39.26 sq.cm

Spacing= 12.50 cm c/c

Say 125 mm c/c

bQ

Mx

105

12


13/18

Steel required at bottom in lateral direction(across width of pier)

Moment= 39.009 t-m

Depth of well cap= 25.32 cm


Area 3.142 sq.cm

Overall depth= 39.32 cm

Say 125 cm




Say 150 mm c/c

Distance from face to of the support upto which radial reinforcement is to be

provided

Location of zero radial moment from centre= 1.47 m

Therefore distance from support= 1.43 m

Add for thickness= 2.13 m

This will be greater of the following

1. Ld=fs/4tbd = 148.44 cm

2. Point of inflection+d 220.75 cm

3. Point of inflection+12f 132.00 cm

Maximum= 220.75 cm

Say 220 cm

3

R

13


14/18

Area of reinforcement /width for -ve B.M. Mr at edges(radial rods)

Moment= 78.018 t-m

Depth of well cap=


Area 4.909 sq.cm

Overall depth= 125.00 cm




Say 125 mm c/c

Column dowel reinforcement:

Tensile stress -142.54 t/sq.m

Tensile force= -57.64 t


Dia of the bar 25.00 mm

Area 4.91 sq.cmSpacing= 16.18 cm c/c

Say 150.00 mm c/c

2

16

2WR

14


15/18

Distribution steel at top


ast= 3.14 sq.cm

Area of steel= @.12% of Ac 15 sq.cm

Spacing 20.94 cm c/c

Say 200 cm c/c

At the edge of slab, the mesh bars are free and are not capable of taking full tension. Therefore

20mm dia at 200 c/c circumferentail steel is provided for a length of up to 1.30m from the inner edgeIn the cntral region provide 20mm dia @ 200 c/c both ways

Check for shear

shear force= 607.91 kN

Shear stress 0.52 N/mm2

% of steel= 3.14 %

correction factor= 1.30 k

Permissible shear stress= 0.44 N/mm2

Permissible Shear stress kt 0.57 N/mm2

Balance shear - N/mm2

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-50.00

0.00

50.00

100.00

150.00

200.00

250.00

0 5.00

STRESS(t/sq.m

)

BASE WIDTH(m)

PIER DESIGN -STRESS AT FOUNDATIONCASE-6 (STRESS ES AT POINT1 & 2)

0.00

50.00

100.00

150.00

200.00

250.00

300.00

0 5.00

STRESS(t/sq.m

)

BASE WIDTH(m)


0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

450.00

0 5.00

STRESS(t/sq.m

)

BASE WIDTH(m)

PIER DESIGN -STRESS AT FOUNDATIONCASE-5. (STRESS ES AT POINT1 & 2)

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

0 5.00

STR

ESS(t/sq.m

)

BASE WIDTH(m)


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17/18

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

0 2.53

STRESS(t/sq.m

)

BASE WIDTH(m)

PIER DESIGN -STRESS AT FOUNDATION

CASE-3(@1 & 3)

0.00

50.00

100.00

150.00

200.00

250.00

0 2.53

STRESS(t/sq.m

)

BASE WIDTH(m)

PIER DESIGN -STRESS AT FOUNDATIONCASE-2(@1 & 2)

122.00

123.00

124.00

125.00

126.00

127.00

128.00

0 5.00

STRESS(t/sq.m

)

BASE WIDTH(m)


0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

0 2.53

STRESS(t/sq.m

)

BASE WIDTH(m)

PIER DESIGN -STRESS AT FOUNDATION

CASE-1(POINT@1 & 3)

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18/18

-200.00

-100.00

0.00

100.00

200.00

300.00

400.00

0 2.53STRESS(t/

sq.m

)

BASE WIDTH(m)

PIER DESIGN -STRESS AT FOUNDATIONCASE-3(POINT@1 & 3)

-200.00

-100.00

0.00

100.00

200.00

300.00

400.00

500.00

0 2.53STRESS(t

/sq.m

)

BASE WIDTH(m)


-50.00

0.00

50.00

100.00

150.00

200.00

250.00

0 2.53

STRESS(t/sq.m

)

BASE WIDTH(m)


0.00

50.00

100.00

150.00

200.00

250.00

300.00

0 2.53

STRESS(

t/sq.m

)

BASE WIDTH(m)


18

Bridge Pier

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