MEGTRO self-supporting Four-legs tubular communication tower
This photo refers to our self-supporting Four-legs tubular communication tower, it is widely used in our Chinese market. Some of technical features of this tower as follow:
MEGATRO self-supporting Four-legs tubular communication tower are mainly fabricated with circular hollow sections which are specially designed to reduce the number of individual members. We strongly believe that less number of tower members means less fabrication time, less handling and storing problem, less erection time, less chances of misplacing, more efficient in term of man hour per tower, higher productivity with a very cost effective solution. The recommend height of this structure is 30m, 45m, 60m and 76m and suitable for either 1~3 operator usage.
MEGATRO self-supporting Four-legs tubular communication tower consists of tower body, platform, lightning rod, ladder, antenna support and other steel components, and by hot galvanized anti-corrosion treatment, mainly for microwave, ultrashort wave, wireless network signal transmission and transmission.
Products Name: Mobile Communication Tower
Application: Communication accessories
Material: Q420/Q235/Q345 or customized
Minimum yield strength: 355mpa
Minimum ultimate tensile strength: 490mpa
Max ultimate tensile strength: 620mpa
Maximum Design Wind Speed: 30m/s
Spare Parts:All necessary parts, e.g. Antenna Mount Pole and Brackets, Climbing Steps, Safety Guide Cable, Lightning Rod, Mounting Bracket for Obstruction Light, Holding Down Bolts/Nuts, And All Other Bolt and Nuts Required for Erection and installation.
Here is the design strength of our Chinese tower bolts
|Item||Grade||Anti-push strength (N/mm2)||Anti-shear strength (N/mm2)|
|Chinese 35 steel||190||/|
|Chinese 45 steel||215||/|
Remark: above technical data only references for our client, we can design every type for our overseas clients.
Cards of quality. And it helps to reduce on-site construction cost due to mismatched assemblies. After fabrication all self-supporting Four-legs tubular communication tower 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. All finished surfaces shall be level and free of tears, burrs, clots and impurities.
Except otherwise specified elsewhere in the specification, the surface treatment and corrosion protection for all metal parts shall be in conformity with the latest revision of the standards listed below:
ASTM A 123 zinc (hot-dipped galvanized) coating on iron and steel products
DIN 55928 Protective painting of steel structure instructions
DIN 55945 Painting materials-Notions
DIN 18363 Paint work-Buildings
DIN 18364 Surface protection work for steel
DIN 53210 Determination of rust degree
DIN 55151 Determination of adhesion
ISO4628/3 Determination of rust penetration
MEGATRO' self-supporting Four-legs tubular communication tower systems can accommodate a variety of cross-arm. MEGATRO also offers a wide variety of accessories and mounts.
Availability size: Based on the customer's requirements.
Material: Chinese material or as per clients requirement
Tower loading legs: Chinese steel Q420B, which equivalent to ASTM A572 GR60
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 Huckbolt 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.
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 ton
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.
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.
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.
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.
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.
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.
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.
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.
Where necessary to avoid distortion of the holes, holes close to the points of bends shall be made after bending.
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.
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.
All holes shall be spaced accurately in accordance with the Drawings and shall be located on the gauge lines.
The maximum allowable variation in hole spacing from that indicated on the Drawings for all bolt holes shall be 0.8 mm.
A specification for tolerances shall be submitted for approval by the Engineer prior to commencement of fabrication.
A complete list of bolts showing their lengths and the members, which they are to connect shall be given on the erection diagrams.
Each steel tower shall be provided with step bolts on one of the legs for single circuit steel tower and on two diagonally opposite legs for double circuit steel tower from approximately 2.5 meters above ground level to the cross arm and from thereon to each ground wire peak. Step bolts shall be furnished for each leg extension in an amount of 25% of the step bolt holes. These bolts shall not be less than 16 mm or 3/4" diameter, double nut type, 18 cm or 7" long with 35 mm or 1 5/8"diameter, symmetrical head, two hexagon nuts and spring washers, spaced not more than 45 cm or 18" apart. Each bolt shall withstand without permanent deformation a vertical load of at least 137 kg applied at the bolt head. If any technical specification, we will discuss with our client and confirm before mass production.
Locking devices for tower bolts will not be required, but point punching shall be performed.
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.
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.
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.
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.
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.
Approval shall be secured from the Engineer if galvanizing is done outside of the Contractor's plant.
All galvanized steelwork shall be protected against white storage stain by using an approved dichromate solution treatment immediately following galvanizing.
Shop Assembly and Inspection
All built-up assemblies shall be shop bolted complete with washers, after galvanizing, and shipped as a unit. When specified in the Purchase Order, MEGATRO shall completely assemble in the presence of Owner one (1) structure of each type before the first shipment of such structures. Any errors in the shop detail drawings or shop work shown by this assembly shall be immediately corrected. MEGATRO's proposal shall include the work required for these shop assemblies. Any material rejected by Owner for failure to conform with this specification or the Purchase Order shall be corrected or replaced by MEGATRO. The fact that material has been inspected, or Owner has waived the right to inspect any material, shall not prevent rejection of the material if it is found not to be in proper condition o r to have fabrication inaccuracies preventing proper assembly.
Design Calculations and Drawings
Our MEGATRO can perform complete design calculations, design drawings and shop detail drawings of each structure and submit checked calculations and drawings for Owner's review and distribution in the quantity, manner and time set forth in the Purchase Order. Our drawings consist of the following:
Design drawings showing structure dimensions, conductor clearance diagrams and schedule of member sizes, bolt sizes and material specifications.
Erection drawings showing each individual member with its identification mark, location and position of outstanding leg of angles, with number, diameter and length of bolts for connection; and typical details to large scale where a number of members frame together.
Shop detail drawings showing all dimensions, draw for tension diagonals, and all shearing punching, bevel cutting, grinding, bending and identification mark for each member.
A complete Bill of Material for each structure showing the number, kind, size, length, weight and identification mark for each member including all bolts.
(Remark: only PO confirmed, our MEGATRO can start shop drawings for client.)
All pieces shall be distinctively marked with erection marks clearly visible after galvanizing, corresponding to those on the erection drawings. Steel tower steel stamping dies, minimum 16 mm or 5/8" high, shall be used and special care shall be taken to see that all erection marks are made in such a manner as not to be obliterated in transit, or in any way damage the galvanizing or impair the strength of the member.
In marking the members, each marking shall be prefixed by letters, which indicate the type of the steel tower. For members that are used in more than one type of steel tower, all steel tower-type designations shall appear on the marking.
In addition, the members shall be marked with water -proof ink stencil 25 mm. or 1.0" high after galvanizing to facilitate in yarding the members and erecting the steel towers.
The diameter and the length of the bolt shall be marked on each bolt end so as to be visible after galvanizing.
An additional Contractor identification mark shall be stamped immediately in front of the piece identification marks. This Contractor identification mark shall be submitted to Owner for acceptance and registration prior to first use.
Identification marks shall be located conspicuously to permit easy reading. Marking of like pieces shall be identical in location, and pieces over 14 feet in length shall be marked at both ends.
Identification marks shall be applied as follows:
Before galvanizing stamp with 2.0mm deep, 15.0mm minimum height steel die letters and numerals. After galvanizing neatly stencil a 6.0mm wide straight line, to underline the identification marks, made with durable paint or ink that will adhere to the galvanized surface and remain legible.
All small items that are not adaptable to die marking and are not boxed shall be identified by either attaching die stamped steel tags or plastic tags with permanent markings. The tags shall be attached with non-corrosive wire.
Preparation for Shipping and Storage
To facilitate segregation of steel tower parts at the stockyard and to maximize the efficiency of erection, packaging of steel towers shall be as follows:
All steel tower parts, including stub angles, plates and steel tower parts member shall be color coded. The color code shall be painted on both ends of the steel tower parts for all angular members and around the edges for plates. The color codes shall be as specified in the Technical Data Sheets. All stub angles shall be packaged per unit steel tower per type i.e., four (4) pieces per bundle.
All cleats including bolts and nuts with spring washers for stub angles shall be packaged per unit steel tower per type in wooden boxes with corresponding color code painted on all corners of the box.
All basic body steel towers shall be packaged per unit steel tower per type. Each package shall not exceed three (3) metric tons. The contents of each package per unit steel tower per type shall be identical for any succeeding unit type. The numbering of each package shall indicate steel tower type (basic), steel tower number and number of pieces included in the package.
MG -Basic/Steel tower No./Package No./Qty. in this package
MG -Basic/ 1 of 200/ 2/ 8
All bolts and nuts with spring washers shall be package in tin cans or wooden boxes per unit steel tower per type and numbered as follows:
MG Bolts (Basic)/Steel tower No./Package No./Quantity
All plates and gussets for the basic steel tower shall be package in wooden boxes per unit steel tower per type and numbered as follows:
MG Plates (Basic)/Steel tower No./Package No./Quantity
All body extension steel tower parts shall be package per unit steel tower per type. The weight of each package shall not be more than three (3) metric tons. The contents of each package per unit per steel tower shall be identical for any succeeding unit steel tower. The numbering of each package shall indicate the steel tower type and extension steel tower number, and number of pieces included in the package.
MG Body Ext./Steel tower No./Package No./Quantity
MG Body Ext./Steel tower No./Package No./Quantity
All bolts and nuts with washers and plates for the body extensions shall be packaged in wooden boxes per unit steel tower per type and numbered as follows:
MG Plates & Bolts/Steel tower No./Package No./Quantity
All steel tower parts/members shall be marked as indicated in the steel tower parts list. The markings shall be embossed, the size of which will be approved by the our client.
All package numbers for the steel tower shall be in label form. The size of the label shall be 5 cm x 10 cm. The label shall be waterproof and all letterings on the label shall be printed. This label shall be attached on every bundle of package. Each bundle or package shall have at least two (2) labels, each label is visible on each side of the bundle.
All bundle or packages for steel tower shall be properly strapped to avoid disintegration of the bundle when subjected to unnecessary impact. The strap shall be properly placed so that the breakage of one (1) or two (2) straps will not allow disintegration of the bundle or package.
Smaller pieces shall be bundled, with all the pieces in any bundle having the same mark.
All small pieces such as bolts and connections for ground wire and insulators shall be packed in boxes of not over 70 kg gross weight each. Bolts of different size or length shall be wrapped in separate sacks before boxing. Description, quantity, bolt size, and length shall be clearly marked on the outside of the sacks and boxes.
When specified in the Purchase Order, bundling and packaging shall be in lots for each individual structure. Boxes or other containers shall be clearly marked to indicate the type of steel tower for which the enclosed material is intended, and the quantity and marks or description of contents shall be shown on the outside.
Shipping shall be as specified by the Purchase Order and shall be in complete steel tower lots. All identifications shown on bundles, boxes or other containers shall be included on Contractor's shipping and packaging lists.
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.
IEC 60826 - Design criteria of overhead lines
IEC 60652 - Loading tests on overhead line structures
ISO 1459 - Metallic coatings - Protection against corrosion by Hot Dip Galvanizing
ISO 1461 - Hot dip galvanized coatings on fabricated iron and steel articles
ISO 12944 - Paint coatings, corrosion protection, and structural steelwork
ISO 898-1 - Mechanical properties of fasteners. Part 1-Bolts, Screws and studs
ISO 630 - Structural Steels - plates, wide flats, bars, sections and profiles
ISO 657 - Hot rolled structural steel plates tolerances on dimensions and shape
ISO 7411 - Hexagon Bolts for high strength structural bolting with large width across flats
ISO 657-5 - Hot rolled Structural Steel Sections equal and unequal leg angles
ISO 7452 - Hot rolled structural steel plates tolerances on dimensions and shape
BS EN 50341-1 - Overhead electrical lines exceeding AC 45kV -General Requirements
BS 8004 - Code of Practice for Foundations
BS 8220 - Structural use of concrete
ANSI10-97 - Design of latticed steel transmission structures
IEC 60050 (151) International Electro-technical Vocabulary
Part 51 Electrical and Magnetic Devices
IEC 60050 (601) Chapter 601: Generation, transmission and distribution of electricity-General
IEC 60050 (601) Chapter 601: Generation, transmission and distribution of electricity-Operation
IEC 60059 IEC standard current ratings
|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/T8220-1995||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|
|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|
|ASTM A6/A6M||Standard specification for general requirements for rolled structural steel bars, plates, and sheet piling.|
|ASTM - 6||- General Requirements for delivery of Rolled Steel Plates, Shapes, sheet Piling Bars for structural used|
|ASTM A36/A36-M-97a||Standard specification for Carbon structural steel|
|ASTM A123 / A123M-02||Standard specification for Zinc (Hot-Dip Galvanized) Coatings on iron and steel products|
|ASTM A143 / A143M-03||Standard Practise for Safeguarding Against Embitterment of Hot-Dip Galvanized Structural Steel Products and Procedure for Detecting Embitterment|
|ASTM A153/ A153M-05||Standard specification for zinc coating (Hot-Dip) on iron and steel hardware|
|ASTM A - 194||- Grade for bolt|
|ASTM A239||Standard practice for locating the thinnest spot in a zinc (Galvanized) Coating on Iron or Steel Articles|
|ASTM A242||Standard specification for High-Strength Low-Alloy Structural steel|
|ASTM A307||Standard Specification for Carbon Steel Bolts and Studs, 60000 PSI Tensile strength|
|ASTM A370-06||Standard Test Methods and Definitions for Mechanical Testing of Steel Products|
|ASTM A325||Standard Specification for structural bolts, steel, Heat treated 120/105 ksi minimum tensile strength|
|ASTM A-325 or A-354||- Galvanized hexagonal head of connection bolt|
|ASTM A325-97||Standard Specification for High-strength Bolts for structural steel Joints|
|ASTM A384 / A384M-02||Standard Practise for Safeguarding Against Warpage and Distortion During Hot-Dip Galvanizing of Steel Assemblies.|
|ASTM A394-93||Standard Specification for steel Transmission Tower, Bolts, Zinc Coated and Bare|
|ASTMA - 563||- Class and size of nuts|
|ASTMA - 572||- Chemical composition of steel|
|ASTM A572/A572-97c||Standard specification for High-Strength Low-Alloy Columbium-Vanadium Structural steel|
|ASTMA - 615||- The anchor bolt material|
|ASTM A673 / A673M-07||Standard Specification for Sampling Procedure for Impact Testing of Structural Steel|
|ASTM B201||Standard practice for testing Chromatic coating on Zinc and Cadmium surfaces|
|ASTM E94-93||Standard Guide for Radiographic Testing|
|ASTM E 709-95||Standard Guide for Magnetic Particle Examination|
|ASCE Manual 72||- Load testing a simple structure|
|ASCE 10-97||Standard Design of latticed steel transmission structures|
|AWS D1.1||American Welding Society D1,1/D1,1M structural Welding code- Steel|
|ANSI B-182-2||Bolts, nuts and washers dimensions|
DIN VDE 0101 - Isokeraunic Level
VDE 0201 - Climatic and environmental conditions
CVDE 0210 - Minimum safety factors under simultaneous working loads
ISO R898 Mechanical Properties of Fasteners
BS EN ISO 1461:1991 - High dip galvanized coatings on fabricated iron and steel articles. Specifications and standards
A) BS 5950: Welding Terms And Symbols
B) BS 729: Hot - Dip Galvanised Coating On Iron And Steel Articles
C) BS 2901: Filler Rods And Wires For Gas Shielded Arc Welding: Part 1 Ferritic Steels
D) BS 3692: ISO Metric Precision Hexagon Bolts, Screws And Nuts
E) BS 4360: Weldable Structural Steel
F ) BS 5135: Metal - Arc Welding Of Carbon And Carbon Manganese Steel
G) BS 5950: Part 1: Code Of Practice For Loading Latticed Tower & Masts
Part 2: Guide To The Background And Use Of Part 1"Code OF Practice For Loading"
Part 3: Strength Assessment of Members
H) DD 133 (1986): Code Of Practice For Loading Latticed Tower & Masts
I) BS 4592 (1987): Part 2: Specification For Expanded Metal Grating Panels
J) BS 4592 (1977): Code Of Practice For Protective Coating Of Iron And Steel Structure Against Corrosion
K) BS 4190: Bracing & Flanged Bolts
L) BS 4190: Rolled Steel sections, Flats & Plates
If any special requirement, we can design and discuss with client.