This photo refers to our 220KV transmission line 220SDJB double circuit tension and ternimal lattice steel tower, with double earth wire. And the earth wire looks like cavel, this tower top peak seems a little different from other type 220SDJB tower due to its cavel shape, and this type tower weight a little higher. Some of their technical data as follow:Â
Tower number  (and tower type) | SDJB ternimal | Application scope | 220KV line |
Design condition | Nominal height(m) | steel weight(kg) | |
Conductor type | 2×LGJQ-300(1) | 18 | 22364.6 |
Earth wire type | 2×LGJ-70/40 | 21 | 25350.8 |
Max.wind speed(m/s) | 30 | 24 | 28940.5 |
Max.ice(mm) | 10 | 27 | 31093.7 |
Horizontal span(m) | 450 | Â | Â |
Vertical span(m) | 650 | Â | Â |
Angle | 0°~ 90° |  |  |
Remark: above technical data only references for our client, we can design every type for our overseas clients.
MEGATRO is a full service engineering company with a global reputation for delivering excellence and innovation in power transmission, transformation, distribution, and telecommunications systems. Our MEGATRO provide and design this 220KV transmission line 220SDJBdouble circuit tension and ternimal lattice steel tower mainly for our Chinese and overseas client. Since 2004, MEGATRO focus mainly international market and had export many kind of transmission structures to overseas clients. MEGATRO has been manufacturing lattice transmission tower & tapered steel poles for lighting, traffic control, communication and utility applications. MEGATRO pioneered the development of transmission tower, telecom tower, substation, and other steel structure and was also at the forefront in the design of Transmission tower.
Over 10 years of experience and innovation in engineering, designing and building towers has evolved MEGATRO into its current form:
- Full Turn-Key provider including site acquisition, engineering services, manufacturing,  field services-DAS, tech services, value added reseller and monitoring, maintenance and network ownership
- Specialize in developing supplying and building wireless and wired networks and in-building telecommunications systems, as well as energy infrastructure
- Single source from Design to System Integration
- Top quality, ISO 9001 registered
MEGATRO mainly design all kinds of towers and posts for:
- Telecoms
- Power transmission
- TV and Radio Broadcast
- Roads and City Development
- Wind energy solution
- Steel structure and workshop
Our complete selection of towers includes:
- Self-supporting
- Monopoles
- Guyed towers
- Custom-designed radar towers
- Broadcast towers
- Power transmission
MEGATRO also designs and manufactures tower related products including:
- Fall protection
- Antenna brackets
- Other accessories if needed by clients
Today, with over 10 years of experience and our commitment to excellence, MEGATRO remains an industry leader in the manufacture and design of steel tubular & angular & monopole structures for all Highway, Municipal, Custom, telecom, lighting and electric Utility applications. MEGATRO has a complete staff of professional engineering personnel trained in the PLS Pole program and three different manufacturing processes for producing steel towers, poles and other supports. We utilize the latest versions of PLS-CADD, PLS-POLE, TOWER, AutoCAD and other CAD software.
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The structure shall be designed according to load combinations given as per IEC 61936-1 and as illustrated below:
Normal loads
1 Dead weight load
2 Tension load
3 Erection load
4 wind load
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Exceptional loads
1 Switching forces
2 short-circuit forces
3 Loss of conductor tension
4 Earthquake forces
Moreover, MEGATRO is fully equipped and qualified to carry out Design Engineering services which includes:
√ Overhead Transmission line steel tower & Telecom steel tower
  Basic Design and Analysis
√ Shop Erection Drawings
√ As-Built Drawings
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MEGATRO performs in-house design activities specializing in electrical overhead transmission &telecom tower steel works, which include wind and earthquake loading, static analysis, stress analysis by finite element methods and fatigue. Our Engineering Department is boasting of highly qualified engineering who are conversant with international codes and standards. The work is carried out with extensive use of CAE/CAD via a large of computer network. The computer hardware & drafting software are liked to the CNC workshop equipment for downloading of information thereby eliminating error and saving valuable production time.
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Besides, MEGATRO is one of the few manufactures who assemble a face of 220KV transmission line 220SDJBdouble circuit tension and ternimal lattice steel tower. This attention to quality may not be the cheapest process but it does insure every tower meets our high standards of quality. And it helps to reduce on-site construction cost due to mismatched assemblies. After fabrication all 220KV transmission line 220SDJBdouble circuit tension and ternimal lattice steel towers are delivered to the galvanizing facility to be Hot DIP Galvanized. Towers are processed through the facility by Caustic Cleaning, Pickling, and then Fluxing. These strict procedures insure years of maintenance free towers. MEGATRO' 220KV transmission line 220SDJBdouble circuit tension and ternimal lattice steel tower systems can accommodate a variety of cross-arm. MEGATRO also offers a wide variety of accessories and mounts.
Other information:
Availability size: Based on the customer's requirements.
Material: Chinese material or as per clients requirement
Steel grades
Tower legs: Chinese steel Q345B, which equivalent to ASTM A572 GR50
Other webs, bracing and not stress plate and angle steel: Chinese Q235B, which equivalent to ASTM A36
Plates: Chinese steel Q345B, which equivalent to ASTM A572 GR50
Bolts: Bolt quality shall be Chinese Class 6.8 and 8.8, as per our Chinese standard, or ISO 898 standard or ASTM A394 type 0,1,2,3 requirements
The anti-theft bolts shall be Huck bolt Fasteners or approved equivalent. The fasteners shall be manufactured from high tensile steel A242 or equivalent and hot-dip galvanized in accordance with ASTM specification A153 and A394.
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Fabrication standard: Chinese Standard or other standard which client accepted
A) Dimension and tolerance for angle are according to GB/T1591-1994, similar to EN 10056-1/2
B) Hot dip galvanization in accordance with GB/T 13912-2002, which similar to ASTM A 123
C) The welding will be performance in accordance with AWS D1.1 or CWB standard
D) All fastener galvanization conform to ASTM A153 requirements.
Package: Both parties discuss before delivery
Port of Loading: Qingdao Port
Lead Time: One month or based on the customer's needs ( for time being our capacity about 5000 tons one month, and can meet client requirements)
Minimum order: 1 set
General Fabrication Requirements
Here is general fabrication requirements for our transmission tower; however, both parties must discuss all drawings and confirm all shop drawings, technical specification, and which standard to conform.
Before mass production, we must received all signed approved shop drawings and technical documents from our client.
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Our Fabrication shall be in strict accordance with detail Drawings prepared by the Contractor and approved by the Engineer. Fabrication shall begin after the approval of the shop assembly and tests.
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Shearing
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Shearing and cutting shall be performed carefully and all portions of the work which will be exposed to view after completion shall be finished neatly. Manually guided cutting torches shall not be used.
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All material over 13 (or 12) mm thick shall be cold sawn or machine flame cut.
Cropping or shearing shall be allowed for material thickness of 13 mm or less.
Flame cutting of high yield steel shall be preceded by a slight preheat operation by passing the cutting flame over the part to be cut.
All flame-cut edges shall be ground clean.
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Bending
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Bending shall be carried out in such a manner as to avoid indentation and surface damage. All bending over 5o, or high yield steel, shall be performed while the material is hot.
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Welding
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No welding shall be done unless prior approval has been obtained from the Engineer.
Welding shall not be allowed at tower attachment points for conductor, shield-wire, insulators or associated assemblies or brackets.
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Sub-punching
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All holes in structural steel less than 10 mm thickness may be punched to full size unless otherwise noted on the approved Drawings. Holes shown on the Drawings as drilled holes and all holes in structural steel 10 mm or more in thickness and tension members of cross-arms shall be drilled or sub-punched and reamed.
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All holes shall be clean cut and without torn or ragged edges. All burrs resulting from reaming or drilling shall be removed. All holes shall be cylindrical and perpendicular to the member.
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Where necessary to avoid distortion of the holes, holes close to the points of bends shall be made after bending.
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Punching
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For punching to full size, the diameter of the punch shall be 1.0 mm larger than the nominal diameter of the bolt, and the diameter of the die shall not be more than 1.5mm larger than the diameter of the punch. For sub-punching, the diameter of the punch shall be 4 mm smaller than the nominal diameter of the bolt, and the diameter of the die shall be not more than 2 mm larger than the diameter of the punch. Sub-punching for reamed work shall be such that after reaming no punch surface shall appear in the periphery of the hole.
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Hole Size
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Where holes are reamed or drilled, the diameter of the finished hole shall be not greater than the nominal diameter of the bolt plus 1.0 mm.
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Accuracy
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All holes shall be spaced accurately in accordance with the Drawings and shall be located on the gauge lines.
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The maximum allowable variation in hole spacing from that indicated on the Drawings for all bolt holes shall be 0.8 mm.
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Fabrication Tolerances
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A specification for tolerances shall be submitted for approval by the Engineer prior to commencement of fabrication.
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Bolt List
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A complete list of bolts showing their lengths and the members, which they are to connect shall be given on the erection diagrams.
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Locking Devices
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Locking devices for tower bolts will not be required, but point punching shall be performed.
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Anti-theft Fasteners
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Appropriate anti-theft fasteners for example Huck-bolting shall be applied on all the towers up to the level of anti-climbing devices, to prevent theft of tower members.
Piece Marks
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All pieces shall be stamped before galvanizing with the piece marks shown on the erection Drawings, with the marking not less than 20 mm high placed in the same relative location on all pieces. The marking shall be plainly visible after galvanizing.
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Galvanizing
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All material shall be hot-dip galvanized after fabrication in accordance with the latest revision of GB/T 13912-2002 or ASTM Specification A 123.
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Material that has been rejected because of bare spots or other coating defects shall either be stripped and re-galvanized, or the uncoated areas shall be recoated by an approved method.
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All plates and shapes which have been warped by the galvanizing process shall be straightened by being re-rolled or pressed. The material shall not be hammered or otherwise straightened in a manner that will injure the protective coating.
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Approval shall be secured from the Engineer if galvanizing is done outside of the Contractor's plant.
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All galvanized steelwork shall be protected against white storage stain by using an approved dichromate solution treatment immediately following galvanizing.
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APPLICABLE STANDARD AND CODES
All towers manufactured and design shall be generally in accordance with latest revision of the following standards except where specifically directed otherwise.
General
IEC 60826Â Â Â -Â Design criteria of overhead lines
IEC 60652Â Â Â -Â Loading tests on overhead line structures
ISO 1459Â Â Â -Â Metallic coatings - Protection against corrosion by Hot Dip Galvanizing
ISO 1461Â Â Â -Â Hot dip galvanized coatings on fabricated iron and steel articles
ISO 12944Â Â Â -Â Paint coatings, corrosion protection, and structural steelwork
ISO 898-1Â Â Â -Â Mechanical properties of fasteners. Part 1-Bolts, Screws and studs
ISO 630Â Â Â -Â Structural Steels - plates, wide flats, bars, sections and profiles
ISO 657Â Â Â -Â Hot rolled structural steel plates tolerances on dimensions and shape
ISO 7411Â Â Â -Â Hexagon Bolts for high strength structural bolting with large width across flats
ISO 657-5Â Â Â -Â Hot rolled Structural Steel Sections equal and unequal leg angles
ISO 7452Â Â Â -Â Hot rolled structural steel plates tolerances on dimensions and shape
BS EN 50341-1Â - Overhead electrical lines exceeding AC 45kV -General Requirements
BS 8004Â Â Â -Â Code of Practice for Foundations
BS 8110Â Â Â -Â Structural use of concrete
ANSI10-97Â Â Â - Design of latticed steel transmission structures
IEC 60050 (151)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â International Electro-technical Vocabulary
                                      Part 51 Electrical and Magnetic Devices
IEC 60050 (601)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Chapter 601: Generation, transmission and distribution of electricity-General
IEC 60050 (601)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Chapter 601: Generation, transmission and distribution of electricity-Operation
IEC 60059Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â IEC standard current ratings
Chinese Standard
No | Code | DESCRIPTION |
1 | GB/T2694-2003 | Power Transmission line Steel tower - Technical requirements for manufacturing |
2 | JGJ81-2002 | Technical specification for welding for steel structure of building |
3 | GB9787-88 | Measuring and allowable tolerance for hot-rolled equal angle |
4 | GB709-88 | Measuring and allowable tolerance for hot-rolled plate and strip |
5 | GB/T699-1999 | Quality Carbon Structural Steel |
6 | GB/T1591-1994 | Low alloy high strength structural Steel |
7 | GB700-88 | Carbon Structural Steel |
8 | GB222-84 | Method of sampling steel for determination of chemical composition and permissible variations |
9 | GB/T228-2002 | Method for Tensile testing of metals |
10 | GB/T232-1999 | Method for Bending test of metals |
11 | GB/T5117-1995 | Carbon Welding Rod |
12 | GB/T5118-1995 | Low Alloy Welding Rod |
13 | GB/T8110-1995 | Welding wires for gas shielding arc welding of carbon and low alloy steels |
14 | GB/T10045-2001 | Carbon steel flux cored electrodes for arc welding |
15 | JB/T7949-1999 | Weld outer dimensions for steel construction |
16 | GB50205-2001 | Test Standard for Acceptance of Steel Structure |
17 | GB/T470-1997 | Zinc Ingot |
18 | GB3098.1-2000 | Mechanical properties of fasteners-Part 1:Bolts, screws and studs |
19 | GB3098.2-2000 | Mechanical properties of fasteners-Part2: Nuts, and thread |
20 | GB3098.3-2000 | Mechanical properties of fasteners-Part3: Fastening screw |
21 | GB/T5780-2000 | Helical Bolts Grade C |
22 | GB/T41-2000 | Helical Nuts Grade C |
23 | GB/T90-2002 | Flat Washer Grade C |
24 | GB/T13912-2002 | Metal Coating, Technical Requirement and Test Method for Hot-dip galvanized Metal Parts |
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American Standards:
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