MONOPOLES FOR MONOPOLES FOR TRANSMISSION & DISTRIBUTION TRANSRAIL LIGHTING LTD Gammon Group Office: Boo ang, 20 /209 Boomrang,A-201/209 Chandivali farm road, Near chandivali studio, Andheri East,Mumbai 400072 M h Maharashtra, h India I di Tel: +91 (22) 40889696 Fax: +91(22) 40889666 Email:
[email protected] q@ URL: www.transraillighting.com Manufacturing Divn: Survey No. No 227/1 ,Khanvel Khanvel kherdi rd; Silvassa -396230 (U.T. Of D & N.H)`
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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 being Is b i used d world ld wide id
MAJOR PRJECTS & CLIENTS
USE OF MONOPOLES IN TRANSMISSION & DISTRIBUTION Transmission Monopoles are Pole Structure used as replacement of Lattice Type Towers. 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 problem off right bl i ht off way is i 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, 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. Above are jjust few cases where Monopole p installation can be the solution.
DESIGN METHODOLOGY Approach to the Design of Transmission line is Similar to the Lattice type structure. etc. is carried in accordance with structure Load Calculation & Line Clearance etc 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. : Code for design & Maintenance of Overhead Power Lines. Lines : Code for Design of Tubular pole for Transmission Line.
IS-5613 -1985 ASCE 48-05
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.
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Longitudinal load – Unbalanced force due to broken wire condition/ Stringing.
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Vertical Load – Dead weight of EW, EW Conductor & other Accessories. Accessories
g parameters All these values varies with respect to the following 1.
Type of line & Deviation angle.
2.
Properties of Conductor / Ground wire.
3.
Normal Span
4.
Wind Pressure Or wind zone.
5.
Specific height requirement / Terrain.
STEPS INVOLED FOR DESIGN OF TRANSMISSION MONOPOLE Step-1
- Decide the Geometry of the Structure & Its Approximate Height.
Step-2
- Wind Pressure Calculation.
Pr cal
Step-3
- Sag Tension Calculation
sag
Step-4
- Prepare Line Clearance Diagram
diagram
Step-5
- Load Calculations ( For Reliability, Security & safety Condition)
Step-6
- Analysis of Monopole structure.
Analysis
Load Calc
DIFFERENT PROFILES OF TUBULAR MONOPOLES
DIFFERENT PROFILES OF TUBULAR MONOPOLES
BASIS OF DESIGN: 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.
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 maintained i t i d below b l th yield the i ld stress t off Pole. P l
Stability & Stress analysis should be carried for each structural element. 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 can perform It f Li Linear & non linear li A l i With Analysis. Wi h the h linear li option i secondary d effect of structure displacement (i.e. P-Delta effect) is ignored, whereas in Non linear analysis P P-Delta Delta effect is considered.
PLS POLE can be run in two modes, Design g Check Mode or allowable span p Mode.
MANUFACTURING UNIT
MAXIMUM USAGE FOR EACH LOAD CASE FOR EACH ELEMENT TYPE
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. 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. section Utility shall be less than 100%. 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 =normall stress t d tto bending due b di fv =shear stress due to shear force ft =shear stress due to torsion fall =allowable (permitted) combined stress defined in ASCE
Standard 48-05. It is based on w/t ((multiple p flats). ) To calculate the unsupported 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. S.F. = Strength Factor for steel poles
Combine Allowable Bending & Axial Stresses for Polygonal Tubular Steel Pole Structures are as follows. For 16 Sided
565< √ Fy *w/t <958
y( y *w/t)) Fb= 0.852*Fy*(1.0-0.000522 √Fy For 12 Sided
p Mpa
630< √ Fy *w/t <958
Fb= 0.870*Fy*(1.0-0.000491 √Fy *w/t) For 8 Sided
for Fy Mpa
for Fy Mpa Mpa
565< √ Fy *w/t <958
Fb= 0.852*Fy*(1.0-0.000434 √Fy *w/t)
for Fy Mpa 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 PLS POLE ¾ ¾ ¾ ¾ ¾ ¾
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Performs Non linear Analysis. Generates Finite Element Model. Inbuilt codal provision for strength check. It has link with the PLS CADD (Wherein it can check for Allowable Span Mode) Pls_pole provides an user friendly interface. One can easily design the complex structures profiles i.e. H-frame , Y-frame ,Aframe etc. It also l check h k deflection d fl ti iin structure. t t It shows the W/T ratio for material strength check. Internationally accepted software for design and analysis and design. A l i and Analysis dd design i off allll ttypes off M Monopoles l – Transmission T i i & Di Distribution t ib ti Monopoles, Guyed Monopoles, Communication Monopoles etc.
CONSTRUCTION OF MONOPOLE Monopoles are Tubular Structures with the uniform Taper throughout the Length. Length It shall have polygonal cross section (i.e. (i e 8 sided, sided 12sided, 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 the connection. As a minimum, slip joints shall be designed to resist 50% 0% off
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
Monopoles p are constructed from High g Tensile steel conforming g to IS 2062 or 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 BASE PLATE WELDING
H.R.COIL SEAM WELDING S.A.W
CUT TO LENGTH
CUT TO LENGTH BENDING TO POLYGON (PRESS BREAK)
HOT DIP GALVANIZING
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 to maintain the Uniformity in thickness.
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
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 qualified lifi d approved d process by b Third Thi d 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 done with ith electrochemical l t h i l and d electro l t deposition d iti processes, the th mostt common method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc. Galvanization shall be confirming to BSEN 1461:1999 or equivalent.
POLE WITH 2-PART INSULATORS ¾
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Areas where electrical clearance is an issue and one can nott able bl to t design d i pole with arms with proper dimensions it can be replaced ep aced by insulated su a ed cross arms (2-part insulator). Use of insulated cross arm also reduce the manufacturing time.
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 intensity it iimposed d on soilil b by ffoundation. d ti Th The mostt iimportant t t aspectt off the foundation design is the necessary check for the stability of foundation under various load conditions. 1 1. Check For Bearing Capacity. Capacity 2. Check for Overturning Resistance. 3. Check For Sliding. 4 4. Check for Uplift. Uplift Structural design of concrete foundation comprises the design of base slab/Pedestal/block. The structural design of different elements of concrete 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 ¾
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Monopole Structure being Cantilever structure ,Moments at the base are critical. Due to heavy Overturning Moment shallow foundations are not cost effective, as the Large base area is required for stability. For Intense Overturning O Moments, Pile foundation f can be economical.
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. 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 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 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 Transferred is T f d by b Bearing. B i I is It i Adopted Ad d in i Hard H d Rock. R k 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. soil Pile foundation Design is Governed by , ¾ Capacity of Pile:- Capacity of Pile depends on its Length & Soil properties. 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 In buried type foundation, resistance to overturning is evaluated assuming that passive are developed above i earth th pressure conditions diti d l d on vertical ti l projections j ti b 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 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. • With this erection is faster.
APPLICATIONS OF MONOPOLE APPLICATIONS OF MONOPOLE p Transmission & Distribution: Monopoles are latest Alternative to Overhead 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: Signage s: structures.
Monopole structures Can be used for Unipole Signage
MONOP POLE FOR R CCTV C CAMERA
MONO OPOLE FO OR TRAN NSMISSION N LINE
MONO OPOLE FO OR TELEC COMMUN NICATION N
CRITERIA FOR DEFLECTION:
Monopole structure being slender structure large deflection can be permitted, as long as it does not affect its utility. 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: Type testing or destruction testing of Monopole structures can be carried out in the similar way as that of Transmission Latticed Tower.
Transmission line Monopoles / distribution Poles can be tested for true scale loading.
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 TEST NO.
TEST CASES
DESCRIPTION
1.
Case 1 (100%)
Reliability condition, 32o C & full wind.
2.
Case 2 (100%)
Reliability condition, 32o C & full wind, Single circuit strung.
3.
Case 3 (100%)
Security condition,32o C & Nil wind, i d TTop conductor d t broken. b k
Case 4 (100%)
Safety condition,32o C & Nil wind, Bottom conductor Stringing Stringing.
4.
5.
6.
Case 5 (100%)
Security condition,32o C & 75% Full wind, Ground wire broken.
Case 6 (100%)
Security condition,32o C & 75% Full wind, Top conductor broken.
Mill test report shall be available for each h major j componentt in i the th test t t structure. Load lines shall be attached to the load point on the prototype in a manner that simulates the inservice application as close as possible. Wind-on-structure loads shall be applied as concentrated loads at selected points on the structure. Load application shall consider the deflected position of structure. Sequence of load cases tested given in tab.1. Testing Facility is available at ‘Deoli
.
Plant‘ at Maharashtra
PROJECTS UNDERTAKEN CLIENT- Adani Town ship & Real estate Ltd. PROJECT- 66Kv D/C 3.1KmsTransmission Line SOFTWARE USEDUSED Pls_Pole (Power Line System) CONDUCTOR – ACSR PANTHER GROUND WIRE- GSW(Galvanized Steel Wire) SPAN- 230 Mts. TYPE OF POLESPA TYPE-
0-2 Deg Suspension monopole
PROJECTS UNDERTAKEN PB TYPE-
0-30Deg Tension Monopole
PC TYPE-
60-90Deg Tension Monopole
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Pole o e Design/Loads es g / oads on o Pole o e Structure St uctu e is s as pe per Loading oad g co condition dto g given e in IS:802(part1/sec1):1995
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Pole analysis is carried as per ASCE/SEI 48-05.
PROJECTS UNDERTAKEN CLIENT-
Jaguar Overseas
PROJECT- Electrification Project of 58 Rural Localities city of Benin ,Distribution poles ¾
Octagonal distribution Poles Description is given below: 13 Mtr- 430 daN 13 Mtr- 990daN 990 13 Mtr-1220 daN 11 Mtr-1250 daN 11.9 Mtr- 430 daN 11.9 Mtr- 990 daN 11.9 Mtr- 1220 daN 14 Mtr- 1250 daN
PROJECTS UNDERTAKEN CLIENT- OIA( Overseas Infrastructure Alliance ) PROJECT- Rural Electrification project ,Mozambique ¾
Octagonal Distribution Pole description MV 11Mtr. LV 8 Mtr.
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.
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The Project using Monopole are less subjected to ROW / Corridor problems. problems
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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 the lattice Structure.
¾Since
the space consumed is less, the spotting shall very well be optimized.
¾Aesthetically
¾Erection E ti
¾As
Monopoles has pleasant appearance.
off monopoles l is i 3 to t 4 times ti f t than faster th normall lattice l tti type t structures t t
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. ¾Monopole
structure being slender & Slip Jointed, has good damping properties. At Steady
wind i d pressure it has h higher hi h Amplitude A lit d off vibration ib ti with ith good d damping d i off about b t 0.2 0 2 – 0.3. 03
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
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Due to heavy Overturning Moment shallow foundations are not cost effective.
¾
As Monopole structure is constructed from the sheet, sheet wastage of Material is Higher.
¾
For installation of Monopole Structure Heavy cranes are required.
CONCLUSION ¾
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¾
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Transmission Line on Monopole can be cost effective in the urban areas, where the land price is high. Transmission T i i Line Li Monopole M l has h pleasant l t appearance & It is i structurally t t ll more stable. t bl 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. 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 g that is adjusted j to satisfyy all the design g criteria. 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
¾
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Poles, being flexible structures, are subjected to considerably large deflections e.g. 1 to 1.5m. 1 5m The major contribution in these deflections is from lateral loads, 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. controlled For angle poles, poles however, however lateral loads are not casual which cause permanent large lateral deflections. 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 poles for l is i usually ll 4mm. 4 Weight of Monopole structure is higher as compared to Lattice Structure.
PROCESSING AN EXPORT ORDER
COST COMPARISON COMPARISON OF MONOPOLE WITH LATTICE STRUCTURE
220 Kv DOUBLE CIRCUIT MONOPOLE SPAN - 300 S 300M CONDUCTOR - ZEBRA
TYPE OF STRUCTURE
BASE WIDTH
WT OF STRUCTURE
R.C.C R C C -M25 M25 Gr
STEEL
APPROX COST
LATTICE TYPE
8M X 8M
5 M.T
5 CU.M
600 KG
3500000
MONOPOLE
2M X 2M
8.1 M.T
35 CU.M
3200 KG
1000000
PROJECTS EXECUTED
Pallekele Cricket Stadium, Kandy
Gandhidham, Kutch
Kudlagi, Bellary
MCA Cricket Stadium, Pune
Punjab University Campus Campus, Chandigarh
Shivaji Terminal Delhi Metro Station, New Delhi
Telecom Monopole, IFFCO Township, Th Thane Paradip
Transrail Lighting Stadium Masts at World Cup Cricket Venue P ll k l (K d ) S k Pallekele(Kandy), Srii L Lanka
PROCESSING AN EXPORT ORDER
THANK YOU
