DESIGN OF BEAM

Description

Materials

Structural Steel

Modulous of Elasticity,E 200000 Mpa

Grade Fe250

Yield Stress 250 Mpa

Hardware

Grade 5.6

Permissible shear stress 310 Mpa

Permissible bearing stress 436 Mpa

Insulator Data

Tension Insulator

Weight/ string 142 kg

Single (1)/Double (2) string 1

Insulator on 1/ both(2) sides 1

Total weight of insulator 1 x 1 x 142 142 kg

Diameter of insulator disks 280 mm

Total length of Insulator 3.5 m

Suspension Insulator

Weight/ string 142 kg

Single (1)/Double (2) string 1

No of Insulators on (0/ 1) 1

Total weight of insulator 1 x 1 x 142 142 kg

Diameter of insulator disks 280 mm

Total length of Insulator 3.1 m

Conductor Data

Type ACSR ZEBRA

Diameter 28.62 mm

Unit Wt 1.620 (kg/m)

No of subconductors/phase 2

1/2 Span on one side = ( 37 - 2.00 - 2 x 3.10 )/2 14.4 m

Broken Span other side = 11.7 m

Mulltiplication factor Weight span 1.1

Jumper Details

Jumper length between tension & suspension insulators 3 m

Jumper length between suspension insulator & equipment 6.5 m

Loads

Conductor Tension

Tension per phase ( normal condition ) 1000 kg

Tension per phase ( short ckt. condition ) 1680 kg

Maximum deviation in Horizontal Plane 0 0

Maximum deviation in Vertical Plane 00

Live Load

Lineman with tool 150 kg

Wind Load

ResultsCalculation

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DESIGN OF BEAM

Description ResultsCalculation

Wind Load on Conductor & Insulators(Refer IS:802-1995 part-I/sec-I)

Wind Zone 4Basic Wind Speed, Vb 47 m/ sec

Factor K0 = 1.375

Reference wind speed, VR = 34.18 m/ sec

Beam level above Ground 11.7 m

Terrain Category 2Reliability level 1

Risk Coefficient, k1 1.00

Terrain, ht & str. size factor, k2 1.00

Design Wind speed, Vd 34.18 m/ sec

Design Wind Pressure, Pd ( 0.6 x 34.182)/ 1000 0.701 kN/m

2

Solidity ratio, f of beam 0.176 f

(For calculation of f, refer sheet ) 0.100Drag Coefficient for Structure, Cdt 3.02 0.200Drag coefficient for conductor, Cdc 1.00 HeightDrag coefficient for groundwire, Cdc 1.20 10Gust response factor, Gc = 1.88 20

Drag coefficient for Insulator, CdI 1.20 HeightGust response factor, GT & GI = 1.97 10

20

Wind pressure on Structure = Pd x Cdt xGT = 4.166 kN/m2

Wind pressure on Insulator = Pd x Cdi x GI x 0.5 = 0.828 kN/m2

Wind pressure on conductor = Pd x Cdc x Gc = 1.317 kN/m2

Factored wind pressure on shieldwire = Pd x Cdc x Gc = 1.581 kN/m2

Factor of Safety

Normal Condition (NC) 2

Short Ckt condition (SC) 1.5

Beam Details

Span 17 m

Hamper Width of Tower 2 m

Clear span 17 - 2 15 m

Phase to phase distance 4.5 m

Beam Width 2.000 m

Beam depth 2.000 m

Bracing Pattern

In Plan Part 1

Type (Prat (P)/ Howe(H)/ Cross (X) P

No of Panels 4

In Plan Part 2

Type (Prat (P)/ Howe(H)/ Cross (X) P

No of Panels 4

In Elevation Part 1

Type (Prat (P)/ Howe(H)/ Cross (X) P

No of Panels 4

In Elevation Part 2

Type (Prat (P)/ Howe(H)/ Cross (X) P

No of Panels 4

Trial SectionsMain leg

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DESIGN OF BEAM

Description ResultsCalculation

Part 1, L1 L90908

Part 2, L2 L1001008

Bracing in Plan Part 1, H1

Diagonals L55556

Verticals ( only for Howe Type)

Bracing in Plan Part 2, H2

Diagonals L45455

Verticals ( only for Howe Type)

Bracing in Elevation Part 1, V1

Diagonals L50506

Verticals ( only for Howe Type)

Bracing in Elevation Part 2, V2

Diagonals L45455

Verticals ( only for Howe Type)

Diaprham (Section X-X)

Verticals, Dv L60605

Horizontals, Dh L60605

Diagonals, Dd L45455

Strain Plate

Length 210 mm

Width 180 mmThickness 12 mm

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