Rcc 4.0c.f Re Wall

DESIGN CONSTANTS HEIGHT ABOVE GROUND LEVEL OVERALL HEIGHT (H) SAFE BEARING CAPACITY Ht. of Stem Unit weight of soil GRADE OF CONCRETE (fck) GRADE OF STEEL (fy) ᶲ µ Ka Kp Surcharge Density of r.c.c Preliminary Dimensions Minimum depth of foundation Provide Foundation Depth Overall Depth Base width Maximum toe Width Provide toe width Thickness of base slab provide thickness of base slab Thickness of stem near base height of stem (h) Pressure at bottom Maximum B.M Mu For Fe 500 steel ( SP 16, P.N. 10)

Mu therefore d provide effective depth d cover provide d Top Width Heel width

= = = = = = = = = = = =

4m 6m 307.34 kN/m^2 5.5 m 18 kN/m^3 20 500 34 0.5 0.283 3.535 20.000 kN/m^2 25.000 kN/m^2

= = =

1.367 m 2m 6m 0.6H-0.7H

= = = = = = = = = = = = = = = = =

5m 1.667 m 1.8 m H/15-H/20

0.400 0.5 m

5.5 m 33.67 kN/m^2 239.796 kN/m^2 359.694 kN/m^2 0.133fckbd^2 367.727 mm 450 mm 50 mm 500 mm 400 mm 2700 mm

Stability Calculation

HORIZONTAL LOAD

Considering seismic action

Load Type

Horizontal load (kN)

perpendicul ar distance (m)

Active earth pressure

91.67

2.00

Earthquake Horizontal force surcharge Ph= Sliding force Overturning Moment

113.65 33.95 239.27

= =

3.60 3

239.270 kN 694.335 kN-m

VERTICAL LOADS W1 = wt. of rectangular portion of stem, per metre length. W2= wt. of triangular portion of stem W3 = wt. of base slab. W4 = wt. of soil on heel slab. W5 = wt due to surcharge

S.No 1 2 3 4 5

Designation W1 W2 W3 W4 W5 ΣW=

ΣW.x= Net moment at toe x= 1.71 eccentricity e = Max pressure P(max) = P(min) = P at junction of stem and toe = P at junction of stem and heel = F.O.S against overturning F.O.S against sliding = Sliding force = Resisting force = F.O.S = Hence Shear key is Required

0.79 < 173.422 < 4.848 > 112.735 65.535 2.099 > 239.270 222.838 0.931 <

Force(kN) 55 6.875 62.5 267.3 54 445.675

Design of stem Pressure at base of stem (P) h At support Mu d At support Mu/bd^2 pt Ast required Ast provided

= = = = = = = =

33.667 kN-m^2 5.000 188.825 kN-m 445.455 0.952 0.245 % 1102.5 mm^2 1339.733 mm^2

Distribution Steel in stem Avg. thickness of stem provide minimum 0.12% steel of bD Ast required Ast provided

450 mm 540 mm^2 560.714 mm^2

Check for shear shear force τv pt τc

τc

Design of toe slab total downward force net pressure net pressure at stem toe junction shear force C.G from stem toe junction B.M at C.G Mu Mu/bd^2 pt Ast Required Ast provided Distribution steel Provide 12% Ast required Ast provided Check for Shear S.F at Critical Shear τv pt (required)

110.1462281213 0.220 N/mm2 0.298 % 0.383 N/mm2

> = = = = = = = = = = = = = = = = = = = = = =

τv

self wt. of toe slab 12.5 kN/m 160.922 100.235 235.041 0.970 227.922 341.883 1.368 0.353 1588.5 mm^2 1674.67 mm^2

600 mm^2 654.167 mm^2 160.443 0.32 N/mm^2 0.35

pt(provided) τc τc

= = = >

0.372 0.42 τv

Design of heel slab Width of Heel total downward pressure upward soil pressure.

2.7 wt of SOIL+ wt of heel slab+ wt of surcharge 355.05 95.02

= =

acting away from heel stem junction towards heel = Total s.f Bending moment Mu Mu/bd^2 pt τv pt τc Ast required Ast provided pt (required) pt(provided)

Distribution Steel Provide pt Ast provided

0.96 = = = = = = = = = = =

= = = = = =

260.03 387.91 581.87 2.327 0.642 0.578 0.64 0.598 3210 mm^2 4088.5417 mm^2 0.64 0.909 0.12 % 785 mm^2

Design of shear key Assume a shear key at a distance of Shear key, height =

0.3 0.3

Width = 2

h1 = m where 300mm loose soil not considered h2 = 3.514 m So, Passive Pressure, Pp = Cp * density of soil * (h2^2-h1^2)/2 Pp = 265.591 Kn FOS sliding = 0.9*(F+Pp)/(Pa2 Cos(∞) + Pa1) FOS sliding = Ast = Half the main reinforcement of stem are anchored in key Ast provided

Ast in shear key

=

=

m m

1.930 > 540 669.867 753.6 mm^2

=

1423.467

3.6 -

-

4.2

0.3

wl^2/12

smic action

moment (kN-m) 183.33

409.15 101.85 Mo =

694.33

Moment perpendicular about distance from toe toe(kN(m) m) 2.1 115.5 1.87 12.83333 2.50 156.25 3.65 975.645 3.65 197.1 MR 1457.33

0.8333333333 SAFE 307.34 SAFE 0 SAFE

1.5 SAFE

1.5 NOTSAFE

No tension at base

sp16 pg48 provide

IS:456-2000 pg 73 X1 (known)= X (known)= X2 (known)=

16 dia bars @

150 c/c

10 dia bars @

140 c/c

0.25 0.30 0.50

net pressure A B C 173.422 112.735

Y1 (known)= Y (unknown)= Y2 (known)=

4.848

16 dia bars @

120 c/c

10 dia bars @

120 c/c

0.36 0.38 0.48

X1 (known)= X (known)= X2 (known)=

0.25 0.37 0.50

SOIL+ wt of heel slab+ wt of surcharge

X1 (known)= X (known)= X2 (known)=

0.75 0.909 1

Y1 (known)= Y (unknown)= Y2 (known)=

0.36 0.42 0.48

net pressure D B 65.535

4.848

Y1 (known)= Y (unknown)= Y2 (known)=

0.56 0.60 0.62

25 dia bars @

120 c/c

10 dia bars @

100 c/c

on lower face

1.8

m from toem from toe

1.5 Safe

mm2 12 dia bars @ 753.6 mm2

> OK

540 mm2

150 c/c

Seismic Force Calculation As per IS:1893-2016 clause 6.2 Horizontal force Fh= αhWm αh= βIαo 0.0875 Fh= 78.58638 Vertical force Fv= αvWm Fh= 112.2663

Fh = αh = Wm = β= I= αo = αv =

Horizontal seismic force to be resisted Design horizontal seismic coeff. Wt. of mass under consideration ignoring reduction due to buoyancy or up Coeff. Depending upon the soil-foundation system Importance factor horizontal seismic coeff. Design vertical seismic coeff.

Z I R Sa/g

Ah

= =

0.36 1.5 3 0.42 0.42

=

0.0378 0.036871 0.038777

Av λ α i

=

0.0252 2.1 0 0

2.21

take maximum

2.21

δ φ

17.33 34

1+Av= 1-Av=

1.0252 0.9748

cos^2(φ-λ-α)= cosλcos^2αcos(δ+α+λ)= sin(φ+δ)sin(φ-i-λ)= cos(α-i)cos(δ+α+λ)=

0.7225 0.9417 0.4113 0.9424

1+Av*cos^2(φ-λ-α)/cosλcos^2αcos(δ+α+λ)= 0.7865 1-Av*cos^2(φ-λ-α)/cosλcos^2αcos(δ+α+λ)= 0.7479 ((1/(1+sqrt((sin(φ+δ)sin(φ-i-λ)/cos(α-i)cos(δ+α+λ)))^2 Ca= Ca=

0.3626

0.2852 2.0624 take maximum Ca= 2.0624

cos^2(φ+λ-α)= cosλcos^2αcos(δ+α+λ)= sin(φ-δ)sin(φ+i-λ)= cos(α-i)cos(δ-α+λ)=

0.7225 0.9417 0.1511 0.9424

1+Av*cos^2(φ-λ-α)/cosλcos^2αcos(δ+α+λ)= 0.787 1-Av*cos^2(φ-λ-α)/cosλcos^2αcos(δ+α+λ)= 0.748 ((1/(1+sqrt((sin(φ+δ)sin(φ-i-λ)/cos(α-i)cos(δ+α+λ)))^2

0.510

Cp= 1.542573 Cp= 1.466738 take minimum Cp= 1.466738

Dynamic earth pressure= Dynamic passive pressure=

296.985 528.026

net seismic acting

113.653

eduction due to buoyancy or uplif

degree radians 2.21 0.0386 0 0.0000 0 0.0000

0.999256201 1.00 1.00

17.33 34

cosα cos(α-i)

1 1

0.3025 0.5934

0.955 0.829

ANNEXURE FOR WIND FORCE

Basic wind speed is considered as

55 m/s as Fig-1 of IS 875 (Part 3).

Design wind speed: (As per Cl. 5.3, of IS: 875) Vz

=

Vb k1 k2 k3

Where, Vz

=

Design wind speed at any height z in m/s;

Vb

=

Basic wind speed

=

55

k1

=

Probability factor (Risk co-efficient) = (From Table 1, for power plant structures)

1

k2

=

Terrain, height and structure size factor (From Table 2, for Terrain Category 2, Class A)

=

k3

=

Topography factor (From Cl. 5.3.3.1, considering ground slop less than 3°)

=

1.0

=

0.6

Design wind pressure, Pz

m/s

As given in the table

Vz²

Where, Pz

=

Design wind pressure in N/m² at height z.

Vz

=

Desing wind velocity in m/s at height z.

WIND PRESSURE ON VARIOUS COMPONENTS ON THE EXPOSED AREA: [Exposed area means effective frontal area ‘Ae’ as indicated in Cl. 6.3; IS: 875 (Part 3)] The wind force on that particular component shall be obtained by multiplying the frontal area ‘Ae’ of that component with the respective wind pressure values as below: Wind Pressure based on height of structure: (Without force co-efficient) The co-efficient shall be as per Table-4, IS: 875 (Part 3) based on the H/B ratio.

Height (m)

k2

Vz (m/s)

Pz (N/m²)

Pz (kg/m²)

Upto 10m

0.91

50.05

1503

151

Horizontal load due to wind on boundary wall Height of boundary wall = 5 m thickness of boundary wa = 0.40 m length of boundary wall = 1 m b/h = 0.2 Cf

= 1.2

F

= Cf*A*Pz = 1.2x2.5x1x1.51 = 9.06 KN

Vertical load of boundary wall = .23x25x2.5 = 14.4 KN