Transmission Monopole

MONOPOLES FOR

MONOPOLES FOR 

TRANSMISSION & DISTRIBUTION

TRANSRAIL LIGHTING LTD

TRANSRAIL LIGHTING LTD

Gammon Group

Survey No 227/1 Khanvel kherdi rd; Survey No. 227/1 ,Khanvel kherdi rd;

INTRODUCTION

Nowadays most of the transmission utilities are facing problems in laying the transmission lines in urban areas due to severe Right of Way problems. This is in view of non availability of adequate land for installation of conventional lattice type towers.

To overcome these practical difficulties, new concept of

I b i d ld id

MAJOR PRJECTS & CLIENTS

MAJOR PRJECTS & CLIENTS

USE OF MONOPOLES IN TRANSMISSION & DISTRIBUTION

Transmission Monopoles are Pole Structure used as replacement of Lattice Type Towers This structure helps countering the constraints as Right of Way or Type Towers. This structure helps countering the constraints as Right of Way or Corridor width. Also for hilly terrains, a Monopole can be conveniently used against a Lattice Tower. The Monopoles adds to the aesthetics of the city too. The Transmission line using a Monopole can be accommodated on Highway Curbs.

These Monopole based lines can give handy solutions to ROW based problems, few of them are mentioned below:

¾Up gradation of line within the existing Corridor can be done using the Transmission line Monopole.

¾ These Monopole based lines can be constructed to feed Power to new industry from existing sub-stations, both situated in city areas, where the

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problem of right of way is severe.

¾ Relocate lines to take care of new railways / metros etc. In almost all metro cities, major work on new trains / Flyover is going on and the existing lines are required to be diverted. Use of Monopole towers can take care of such requirements.

¾ These Monopoles can be used where the Transmission Line is Parallel ¾ These Monopoles can be used, where the Transmission Line is Parallel to road.

¾These Monopoles can be used, where the Transmission Line is Passing through thick forest area, thus minimize the loss to environment.

DESIGN METHODOLOGY

Approach to the Design of Transmission line is Similar to the Lattice type

structure Load Calculation & Line Clearance etc is carried in accordance with structure. Load Calculation & Line Clearance etc. is carried in accordance with the Standards / as per the Customer Specification.

REFERENCE STANDARDS

IS -875 (Part-III) 1987 : Code for Wind Loads on Structure.

IS-802 (Part1/sec1) 1995 : Code for Transmission Line tower ( Material Loads & Permissible stresses.

IS-5613 -1985 : Code for design & Maintenance of Overhead Power Lines

Power Lines.

ASCE 48-05 : Code for Design of Tubular pole for Transmission Line.

INPUT DATA :

For Transmission Monopole Design input data is the forces i.e.

¾ Transverse load – Load on EW & Conductor due to the wind pressure & component

of Mechanical tension due to line angle deviation.

¾ Longitudinal load – Unbalanced force due to broken wire condition/ Stringing.

¾ Vertical Load Dead weight of EW Conductor & other Accessories

¾ Vertical Load – Dead weight of EW, Conductor & other Accessories.

All these values varies with respect to the following parametersg

1. Type of line & Deviation angle.

2. Properties of Conductor / Ground wire. 3. Normal Span

4. Wind Pressure Or wind zone.

STEPS INVOLED FOR DESIGN OF TRANSMISSION MONOPOLE

Step-1 - Decide the Geometry of the Structure & Its Approximate Height.

STEPS INVOLED FOR DESIGN OF TRANSMISSION MONOPOLE

Step-2 - Wind Pressure Calculation.

Step-3 - Sag Tension Calculation sag Pr cal

Step-4 - Prepare Line Clearance Diagram diagram

Step-5 - Load Calculations ( For Reliability, Security & safety Condition)

Step-6 - Analysis of Monopole structure. Analysis

DIFFERENT PROFILES OF TUBULAR MONOPOLES

DIFFERENT PROFILES OF TUBULAR MONOPOLES

BASIS OF DESIGN:

Approach to the calculation is based on the Elastic Limit Principles, Where load effects are compared with ultimate resistance of the structure.

BASIS OF DESIGN: 

In Elastic limit state, strength or Capacity of the pole is assessed by moment of resistance at Elastic Limit & the dimensions are decided. The maximum bending stresses arising out of the calculated bending moments are

i t i d b l th i ld t f P l maintained below the yield stress of Pole.

Stability & Stress analysis should be carried for each structural element. Consideration should be Given to the Load effect Resulting out of deflected Consideration should be Given to the Load effect Resulting out of deflected shape of Structure.

Finite element Model of the Structure shall be developed & Entire pole structure shall be Generated. Member in the deflected shape shall be adequately represented and the point of maximum Stress is adequately defined.

ANALYSIS :

ANALYSIS : 

Analysis of structure is carried using Power line software PLS-Pole. This software allows generating the finite element model of the Monopole by selecting the component & assembling them in to the finished structure.

I f Li & li A l i Wi h h li i d

It can perform Linear & non linear Analysis. With the linear option secondary effect of structure displacement (i.e. P-Delta effect) is ignored, whereas in Non linear analysis P-Delta effect is considered.

linear analysis P Delta effect is considered.

PLS POLE can be run in two modes, Design Check Mode or allowable spang p Mode.

DESIGN CHECK

DESIGN CHECK

• PLS -POLE can be run in two modes, Design Check Mode or allowable span

Mode.

STRENGTH CHECK:

PLS-POLE checks the section strength as per following standards. ASCE /SEI

¾ ASCE /SEI

¾ TIA / EIA -222F ¾ ANSI / TIA 222-G

Design checks

For each design load case, the analysis produces axial, bending, shear, and torsional stresses at the ends of each tubular element or at every Nodal point. Then Combine effect of these Stresses is Checked with the allowable stresses at that particular section Utility shall be less than 100%

ASCE STRENGTH CHECK

For transmission poles designed according to ASCE/ SEI Standard 48-05 (ASCE, 2006) the strength usage is calculated at each of the Nodal points as: SQRT { (fa + fb )2 + 3 (fv + ft )2 } / ( fall x S.F.)

Where: fa =normal stress due to axial load

fb l t d t b di

fb =normal stress due to bending fv =shear stress due to shear force ft =shear stress due to torsion

ft =shear stress due to torsion

fall =allowable (permitted) combined stress defined in ASCE Standard 48-05. It is based on w/t (multiple flats). To calculate the unsupported( p ) pp flat width "w", it is assumed that a steel plate bending radius of 4 times the plate thickness is used. For a corner point, w/t is the largest of the values for the two adjacent flat faces.

Combine Allowable Bending & Axial Stresses for Polygonal Tubular Steel Pole Structures are as follows.

Structures are as follows.

For 16 Sided 565< √ Fy *w/t <958 for Fy Mpa Fb= 0.852*Fy*(1.0-0.000522 √Fy *w/t)y ( y ) Mpap

For 12 Sided 630< √ Fy *w/t <958 for Fy Mpa Fb= 0.870*Fy*(1.0-0.000491 √Fy *w/t) Mpa

For 8 Sided 565< √ Fy *w/t <958 for Fy Mpa Fb= 0.852*Fy*(1.0-0.000434 √Fy *w/t) Mpa

Where,

Fy – Yield Strength

Fb – Allowable Combine bending & Axial Stress. t – Wall Thickness

w – Actual Flat side dimension but not less than dimension calculated using bend radius equal to 4t.

FEATURES OF PLS POLE

FEATURES OF PLS_POLE

¾ Performs Non linear Analysis. ¾ Generates Finite Element Model.

¾ Inbuilt codal provision for strength check.

¾ It has link with the PLS CADD (Wherein it can check for Allowable Span Mode) ¾ Pls_pole provides an user friendly interface.

¾ One can easily design the complex structures profiles i.e. H-frame , Y-frame

,A-frame etc.

It l h k d fl ti i t t

¾ It also check deflection in structure.

¾ It shows the W/T ratio for material strength check.

¾ Internationally accepted software for design and analysis and design.

A l i d d i f ll t f M l T i i & Di t ib ti

¾ Analysis and design of all types of Monopoles – Transmission & Distribution

CONSTRUCTION OF MONOPOLE

Monopoles are Tubular Structures with the uniform Taper throughout the Length It shall have polygonal cross section (i e 8 sided 12sided 16sided) Length. It shall have polygonal cross section (i.e. 8 sided, 12sided, 16sided) and shall be continuously tapered with longitudinal welding. There shall not be any circumferential welding. Monopoles shall be of two or more section with telescopic joint as per the required height.

To join two or more sections either of two joints are being used: 1.Slip Joint

2.Flange joint Slip joint:

Slip joints shall be designed to resist the maximum forces and moments at 0% f the connection. As a minimum, slip joints shall be designed to resist 50% of

CONSTRUCTION OF MONOPOLE

moment capacity of the lower strength tube. Taper above and below the joint shall be the same.

FLANGE JOINT:

Flange joints shall be designed to resist the maximum forces and moments at the connection. As a minimum, slip joints shall be designed to resist 50% of moment capacity of the lowest strength tube. Flexure stress in flange connection shall not exceed the specified minimum yield stress

connection shall not exceed the specified minimum yield stress

Monopoles are constructed from High Tensile steel conforming to IS 2062 orp g g

BSEN 10025 and cut in Trapezoidal shape and folded by pressing to required angle and Welded Longitudinally to form Polygonal section.

PROCESS OF MANUFACTURING: HIGH MASTS

CUT TO LENGTH

CUT TO LENGTH

H.R COILS are loaded on the Cut To Length machine.

C.T.L Machine Cuts the Coil in required width & and applies constant pressure width & and applies constant pressure to maintain the Uniformity in thickness.

PRESS BREAK MACHINE

PRESS BREAK MACHINE

FOLDING:

After cutting the coil in the required trapezium. It is then folded to the numbers of folds. By applying the load under the press break machine.

WELDING

There shall not be any circumferential welding. The welding of pole shaft shall be done by Submerged Arc Welding (SAW) process.

All Monopole shafts shall be provided with the rigid flange plate of suitable thickness with provision for fixing thickness with provision for fixing foundation bolts. This base plate shall be fillet welded to the Monopole shaft at two locations i.e. from inside and outside. The welding shall be done as per

lifi d d b Thi d

qualified approved process by Third Party Inspection agency.

Metal protection:

For metal protection of the Monopole, the entire fabricated Monopole is hot dip galvanized internally and externally.

Galvanization is the process of applying a protective zinc coating to metal, in order to prevent rusting and galvanic corrosion. Although galvanization can be

d ith l t h i l d l t d iti th t

done with electrochemical and electro deposition processes, the most common method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc.

submerged in a bath of molten zinc.

POLE WITH 2-PART INSULATORS

¾ Areas where electrical

clearance is an issue and t bl t d i one can not able to design pole with arms with proper dimensions it can be

replaced by insulated ep aced by su a ed cross arms (2-part insulator).

¾ Use of insulated cross arm

also reduce the manufacturing time.

FOUNDATION

FOUNDATION

The design of foundation consists of two parts – Stability analysis and structural design of foundation. The following subsection describes in detail about the two aspects.

Stability analysis aims at eliminating the possibility of failure of foundation by tilting, overturning, uprooting and siding due to load

i t it i d il b f d ti Th t i t t t f

intensity imposed on soil by foundation. The most important aspect of the foundation design is the necessary check for the stability of

foundation under various load conditions.

1 Check For Bearing Capacity 1. Check For Bearing Capacity.

2. Check for Overturning Resistance. 3. Check For Sliding.

4 Check for Uplift 4. Check for Uplift.

Structural design of concrete foundation comprises the design of base slab/Pedestal/block. The structural design of different elements of

slab/Pedestal/block. The structural design of different elements of concrete foundation.

TYPE OF FOUNDATION

TYPE OF FOUNDATION

Different Types of Foundation Are;

¾ Shallow foundation / Raft Foundation ¾ Pile foundation

¾ Buried foundation / Block Foundation

selection of type of foundation depends on various parameters such as,

1. Type of soil / soil stratum. 2. Intensity of load.

3. Space availability. 4. Economy.

¾ Monopole Structure being Cantilever structure ,Moments at the base are critical. ¾ Due to heavy Overturning Moment shallow foundations are not cost effective, as

the Large base area is required for stability.

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SHALLOW FOUNDATION

SHALLOW FOUNDATION

Shallow foundations can be recommended for the Lower intensity Loading. Shallow foundation Design is Governed by ,

¾ S.B.C of Soil :- Size of foundation & its dimensions are governed by S.B.C of Soil. Gross Pressure shall be maintained Lower than S.B.C of Soil.

¾ Stability Against Overturning :- To prevent the overturning / Tilting of

foundation at toe, foundation size is decided so that the Restoring Monet due to dead Load is greater than overturning Moment For Economic design to dead Load is greater than overturning Moment. For Economic design Earth cone shall be considered for Calculating the Dead Load ,Also Uplift of 20% can be permitted.

¾ Stability Against Sliding :-The friction between bottom of the footing and soil ¾ Stability Against Sliding : The friction between bottom of the footing and soil

resist the sliding of footing and shall be considered in the stability of foundation against sliding.

PILE FOUNDATION

PILE FOUNDATION

For the Structures where the large moments are to be transferred to the Substructure, Pile Foundation shall be adopted.

Type of Pile are classified as,

1. End Bearing pile :- In this case the Pile is socketed in Hard Stratum & Load

i T f d b B i I i Ad d i H d R k

is Transferred by Bearing. It is Adopted in Hard Rock.

2. Friction Pile :- In this Load Transfer is by the negative Skin Friction, that

develops between the wall of Pile & Soil in contact with it. It is Adopted in Cohesive soil

Cohesive soil.

Pile foundation Design is Governed by ,

¾ Capacity of Pile:- Capacity of Pile depends on its Length & Soil properties

¾ Capacity of Pile:- Capacity of Pile depends on its Length & Soil properties.

¾ No of Pile:- Based on the Capacity of Pile, No of pile & its arrangement required to carry the tension or compression is decided.

BURIED FOUNDATION

BURIED FOUNDATION

In buried type foundation, resistance to overturning is evaluated assuming that

i th diti d l d ti l j ti b

passive earth pressure conditions are developed on vertical projections above the toe of foundations.

Buried Type foundations are the Most Economical Foundations. It can be adopted for the structures where the Moment at the Base are less For Antenna adopted for the structures where the Moment at the Base are less.For Antenna Monopoles Buried Type foundation can be used, As the design is governed by the Deflection & moments at the base of monopole are less

Advantage of Buried foundation:

• For buried foundation base flange is not required. • For buried foundation Bolts are not required.

APPLICATIONS OF MONOPOLE

APPLICATIONS OF MONOPOLE

Transmission & Distribution: & Monopoles are latest Alternative to Overhead p

Transmission Lines lattice type self supporting towers. Widely being used in Gulf & European Countries.

CCTV Mast: Monopole structures are also used for mounting of CCTV

Cameras.

Telecommunication: Monopole structures are ideal for mounting antennas

for telecommunication.

Signage's: Monopole structures Can be used for Unipole Signage Signage s: Monopole structures Can be used for Unipole Signage

MON O N LINE _O POLE F O C AMERA N SMISSIO N O R TELE C R CCTV C O R TRA N C OMMU N P OLE FO R O POLE F O N ICATIO N MONO P MON O N

CRITERIA FOR DEFLECTION:

Monopole structure being slender structure large deflection can be permitted, as long as it does not affect its utility

as long as it does not affect its utility.

As there is no criteria for deflection, where deflection is considered critical it may be limited to 5% of the total height.

TRUE SCALE TESTING

TESTING: TESTING:

Type testing or destruction testing of Monopole structures can be carried out in the similar way as that of Transmission Latticed Tower.

/

ƒ Transmission line Monopoles /

distribution Poles can be tested for true scale loading.

scale loading.

ƒ The prototype shall be made of material

that is representative of the material that will be used in production.

Completely Automatic Tower Testing Station (Upto 85m

Structure) - Gammon Plant at Deoli

TRUE SCALE TESTING

ƒ Mill test report shall be available for

h j t i th t t TEST NO. TEST CASES DESCRIPTION

each major component in the test structure.

ƒ Load lines shall be attached to the

load point on the prototype in a 1. Case 1

(100%)

Reliability condition, 32o _{C & full wind.}

2. Case 2 Reliability condition, _{load point on the prototype in a} manner that simulates the in-service application as close as possible.

2. Case 2 (100%)

Reliability condition, 32o _{C & full wind, Single}

circuit strung. 3. Case 3

(100%)

Security condition,32o _{C & Nil}

i d T d t b k _{ƒ Wind-on-structure loads shall be} applied as concentrated loads at selected points on the structure. Load application shall consider the (100%) wind, Top conductor broken.

4. Case 4 (100%)

Safety condition,32o _{C & Nil}

wind, Bottom conductor

Stringing ƒ Load application shall consider the

deflected position of structure.

ƒ Sequence of load cases tested

given in tab.1. Stringing.

5. Case 5 (100%)

Security condition,32o _{C &}

75% Full wind, Ground wire

broken. _{given in tab.1.}

ƒ Testing Facility is available at ‘Deoli

Plant‘ at Maharashtra

.

(100%)

Security condition,32o _{C &}

75% Full wind, Top conductor broken.

PROJECTS UNDERTAKEN

PROJECTS UNDERTAKEN

CLIENT- Adani Town ship & Real estate Ltd.

PROJECT- 66Kv D/C 3.1KmsTransmission Line

SOFTWARE USED

SOFTWARE USED- Pls_Pole (Power Line System)

CONDUCTOR – ACSR PANTHER

GROUND WIRE- GSW(Galvanized Steel Wire) SPAN- 230 Mts.

TYPE OF

PROJECTS UNDERTAKEN

PROJECTS UNDERTAKEN

PB TYPE- 0-30Deg Tension Monopole PC TYPE- 60-90Deg Tension Monopole

¾ Pole Design/Loads on Pole Structure is as per Loading condition given in o e es g / oads o o e St uctu e s as pe oad g co d t o g e

IS:802(part1/sec1):1995

PROJECTS UNDERTAKEN

PROJECTS UNDERTAKEN

PROJECT- Electrification Project of 58 Rural Localities city of Benin ,Distribution poles

¾ Octagonal distribution Poles Description is given below: ƒ 13 Mtr- 430 daN 13 990 ƒ 13 Mtr- 990daN ƒ 13 Mtr-1220 daN ƒ 11 Mtr-1250 daN ƒ 11.9 Mtr- 430 daN ƒ 11.9 Mtr- 990 daN ƒ 11.9 Mtr- 1220 daN ƒ 14 Mtr- 1250 daN

PROJECTS UNDERTAKEN

PROJECTS UNDERTAKEN

PROJECT- Rural Electrification project ,Mozambique

¾ Octagonal Distribution Pole description ƒ MV 11Mtr.

ADVANTAGE OF MONOPOLE STRUCTURE

ADVANTAGE OF MONOPOLE STRUCTURE

¾ Space consumed by a monopole compared to a lattice structure of same capacity is much

less. Hence monopole structures become suitable for heavily populated and congested areas like metros and other cities.

¾ The Project using Monopole are less subjected to ROW / Corridor problems ¾ The Project using Monopole are less subjected to ROW / Corridor problems.

¾ As the Number of Pieces of monopoles are much lesser than the Lattice tower Structure

the chances of failure are less.

¾ Poles are subjected to lesser wind load as compared to Tower structure, Due to smaller

aerodynamic coefficient.

¾ Poles being Continuum Type offer more resistance to terrorist activities as compared with ¾ Poles being Continuum Type offer more resistance to terrorist activities as compared with

¾Since the space consumed is less, the spotting shall very well be optimized.

¾Aesthetically Monopoles has pleasant appearance.

E ti f l i 3 t 4 ti f t th l l tti t t t

¾Erection of monopoles is 3 to 4 times faster than normal lattice type structures

¾As the Body width of Monopole Structure is smaller than, Lattice Structures it helps in

Reduction physical dimensions as per the Clearances required. Pole Structures Should be Considered Flexible & Relatively large Deflections can be permitted. The deflection of Structure & Swing of Insulator can Significantly decrease wire Tension.

Structure & Swing of Insulator can Significantly decrease wire Tension.

¾Monopole structure being slender & Slip Jointed, has good damping properties. At Steady

i d it h hi h A lit d f ib ti ith d d i f b t 0 2 0 3 wind pressure it has higher Amplitude of vibration with good damping of about 0.2 – 0.3.

LIMITATIONS OF POLE STRUCTURES

LIMITATIONS OF POLE STRUCTURES

¾ As compared to the Lattice structure, monopoles are expensive.

¾ Monopole Structure being Cantilever structure ,Moments at the base are critical

¾ Due to heavy Overturning Moment shallow foundations are not cost effective.

¾ As Monopole structure is constructed from the sheet wastage of Material is ¾ As Monopole structure is constructed from the sheet, wastage of Material is

Higher.

CONCLUSION

¾ Transmission Line on Monopole can be cost effective in the urban areas, where the land

price is high.

T i i Li M l h l t & It i t t ll t bl

¾ Transmission Line Monopole has pleasant appearance & It is structurally more stable. ¾ Limiting the defection to one or one half percent (1 or ½%) of the structure height under

construction loading can eliminate the need for back guying structures during construction. For appearance, limiting deflections to five or ten percent (5 or 10%) of the structure height under maximum loading can keep a pole in a position. Another technique that is used to keep steel pole structure appearance aesthetically pleasing is to camber or rake the structures before erection. Cambering or raking makes the structure initially deformed so that when load is applied to the structure, it tends to become straight or appears less deformed.

¾ Sometimes, client restricts the base diameter due to space or other constraints that

indirectly limit the amount of taper. In such a case, the design output is only the wall thickness of pole segments that is adjusted to satisfy all the design criteria.g j y g

¾ In steel pole structures, the maximum allowable stress on the pole is related to the width

to thickness ratio for structures with polygonal cross-sections and by diameter to thickness ratios for structures with circular cross-sections.

¾ Poles, being flexible structures, are subjected to considerably large deflections e.g.

1 to 1 5m The major contribution in these deflections is from lateral loads which 1 to 1.5m. The major contribution in these deflections is from lateral loads, which are further increased by vertical loads due to P-Δ effects. For the tangent poles, this large deflection will be infrequent and occasional in its entire life span (i.e. when it is subjected to worst possible high wind/lateral loading). Hence, these large deflections need not to be controlled For angle poles however lateral loads large deflections need not to be controlled. For angle poles, however, lateral loads are not casual which cause permanent large lateral deflections.

¾ Most of the poles consist of 3 to 4 segments. A single pole segment usually has an

economical and optimal length of 12m. The minimum thickness of material used f l i ll 4

for poles is usually 4mm.

COST COMPARISON

COST COMPARISON

COMPARISON OF MONOPOLE WITH LATTICE STRUCTURE

220 Kv DOUBLE CIRCUIT MONOPOLE

SPAN - 300M

S 300

CONDUCTOR - ZEBRA

WT OF R C C M25 TYPE OF STRUCTURE BASE WIDTH WT OF

STRUCTURE

R.C.C -M25

Gr STEEL APPROX COST

LATTICE TYPE 8M X 8M 5 M.T 5 CU.M 600 KG 3500000

PROJECTS EXECUTED

PROJECTS EXECUTED

Kudlagi, Bellary _{MCA Cricket} Stadium, Pune

Punjab University Campus

Shivaji Terminal

Delhi Metro Telecom Monopole, _Th IFFCO Township, Campus,

Transrail Lighting Stadium Masts at World Cup Cricket Venue

-P ll k l (K

d ) S i L k

PROCESSING AN EXPORT ORDER

PROCESSING AN EXPORT ORDER

THANK YOU

THANK YOU