Design Struts Beam B1 B2 Bend Forces 04-02-14

8/12/2019 Design Struts Beam B1 B2 Bend Forces 04-02-14

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1

PIPE BEND FORCES


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Design of Strut (Beam

B1):

Force in the strut = 2.60 kN

Max. unsupported length of the strut = 2.785 m

Factored load = 2.6 1.5 = 3.9 kN

Size of the strut = 300 300 mm

Characteristic strength of concrete = 30 N/mm

Characteristic strength of reinforcement = 500 N/mm

Clear cover = 25 mm

Minimum eccentricity as per Cl.25.4, IS 456:2000 =30

300

500

2785

= 15.57 mm < 20mm

Moment due to minimum eccentricity = 0.02 3.9

= 0.078 kNm

Since the strut is monolithically constructed with Column, strut is assumed to be

held in position and direction at both ends

Effective length of strut (table 28, IS 456:2000) = 0.65 2785 = 1810 mm

Slenderness ratio (Cl.25.1.2, IS 456:2000) =300

1810= 6.03

= 6.03 < 12

Hence no slender

Self weight of the strut = 0.3 0.3 25

= 2.25 kN/m


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Bending moment due to self weight =10

785.225.25.1 2xx

= 2.62 kNm

Bending moment about major axis = 0.078 + 2.62

= 2.70 kNm

Bending moment about minor axis = 0.078 kNm

Provided longitudinal reinforcement = 4 - #12 mm (452 mm)

(0.50% of cross sectional area)

Check for combined axial load and biaxial bending as per Cl 39.6 of IS: 456 - 2000

bDf

Pu

ck

=30030030

100090.3

xx

x

= 0.0014

Corresponding uniaxial moment capacity

D

d'

=300

31 = 0.10

Reference to SP-16, chart 48

ckf

p =

30

1 = 0.033

2

ck

1ux

bDfM = 0.040

Mux1 & Muy1 = 0.040 30 300 300

= 32.40 kNm


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Puz = 0.45 30 (300 300 452) + 0.75 500 452

= 1378.40 kN

uz

u

P

P =

40.1378

90.3 = 0.0028

n = 1

Interaction ratio

0.10.1

40.32

078.0

40.32

70.2

= 0.08+ 0.0024 = 0.082 < 1 Hence safe


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Design of Strut (BeamB2):

Force in the strut = 86.10 kN

Max. unsupported length of the strut = 5.57 m

Factored load = 86.10 1.5 = 129.15 kN

Size of the strut = 300 300 mm

Characteristic strength of concrete = 30 N/mmCharacteristic strength of reinforcement = 500 N/mm

Clear cover = 25 mm

Minimum eccentricity as per Cl.25.4, IS 456:2000 =30

300

500

5570

= 21.14 mm > 20mm

Moment due to minimum eccentricity = 0.021 129.15

= 2.71 kNm

Since the strut is monolithically constructed with Column, strut is assumed to be

held in position and direction at both ends

Effective length of strut (table 28, IS 456:2000) = 0.65 5570 = 3620 mm

Slenderness ratio (Cl.25.1.2, IS 456:2000) =300

3620 = 12.10

= 12.10 > 12

Hence slender column

Additional moment (Cl.39.7.1, IS 456:2000) = 210.122000

3.015.129x

x

= 2.84 kNm > 2.71 kNm


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Self weight of the strut = 0.3 0.3 25

= 2.25 kN/m

Bending moment due to self weight =10

57.525.25.1 2xx

= 10.48 kNm

Bending moment about major axis = 2.84 + 10.48

= 13.32 kN-m

Bending moment about minor axis = 2.84 kNm

Provided longitudinal reinforcement = 8 - #12 mm (904 mm)

(1% of cross sectional area)

Check for combined axial load and biaxial bending as per Cl 39.6 of IS: 456 2000

bDf

Pu

ck

=30030030

100015.129

xx

x

= 0.048

Corresponding uniaxial moment capacity

D

d'

=300

31 = 0.10

Reference to SP-16, chart 48

ckf

p =

30

1 = 0.033

2

ck

1ux

bDf

M = 0.06

Mux1 & Muy1 = 0.06 30 300 300

= 48.60 kNm


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Puz = 0.45 30 (300 300 904) + 0.75 500 904

= 1541.79 kN

uz

u

P

P =

79.1541

15.129 = 0.08

n = 1.0

Interaction ratio

0.10.1

60.48

84.2

60.48

32.13

=

= 0.27 + 0.05 = 0.32 < 1 Hence safe


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Design of Encasement : ( 3.26 x 2.50 x 2.83m deep )

a) Load due to 2200dia (water pipe)

102.24

2

= 38 kN/m

Unit weight of water = 10 kN/m3

5.78)2.2232.2(4

22

= 8.75 kN/m (self wt. of pipe)

UDL = 38 + 8.75 = 46.75 kN/m

Load = 46.75 x 5 = 233.75 kN

b) Reaction due to flow velocity (1000 dia Pipe) = 77.0 kN

c) self weight of encasement (RCC Block) = 22.24

)26.383.2(

2

42.580.322.9 m

kN1.339255.242.5

Total Load = 233.75 + 77.0 + 339.11 = 649.86 kN say 650 KN

Bearing pressure = 2/75.795.226.3

650mkN

8.0 T/m2

< 15 T/m2


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Design of 20mm dia Bolt:

Total shear force = 4 T

No. of bolts provided = 8 nos

Shear force on each bolt =8

4 = 0.50 T

area of the Bolt = 20.24

= 3.14 cm2

Permissible shear stress = 800 kg/cm2

(as per IS : 800 , Table : 8.1)

Capacity of bolt (shear) = Tkg 51.2251280014.3

0.50 T < 2.51 T ; Hence safe.

Total horizontal force = 4 T

Moment = 4 x 0.70 = 2.80 Tm

c / c of bolt = 0.35 m

Tension in the bolt =35.0

80.2= 8.0 T

No. of bolts (Tension) = 4 nos

Tension on each bolt = 4

8

= 2.0 T

Total compressive force = 6.80 T


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Compressive force on each bolt =8

8.6 = 0.85 T

Net tension in the bolt = 2.0 0.85 = 1.15 T

Net area of the Bolt = 28.00.24

= 2.01 cm2

Permissible stress (Tension) = 1200 kg/cm2

(as per IS : 800 , Table : 8.1)

Capacity of bolt (Tension) = Tkg 41.22412120001.2

= 1.15 T < 2.41 T ;

Hence safe.

Design Struts Beam B1 B2 Bend Forces 04-02-14

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