20-TMSS-01-R0

TRANSMISSION MATERIALS STANDARD SPECIFICATION

20-TMSS-01, Rev. 0

TABLE OF CONTENTS 1.0

SCOPE

2.0

CROSS REFERENCES

3.0

APPLICABLE CODES AND STANDARDS

4.0

DESIGN AND CONSTRUCTION REQUIREMENTS 4.1 4.2 4.3 4.4 4.5

5.0

Design Materials Detailing Fabrication Markings

INSPECTION AND TESTING 5.1 5.2

Inspection Requirements Testing Requirements

6.0

PACKING AND SHIPPING

7.0

DOCUMENTATION REQUIREMENTS 7.1 7.2

8.0

General Drawings

DATA SCHEDULE

20TMSS01R0/MAA

Date of Approval: August 20, 2006

PAGE NO. 2 OF 30


1.0

20-TMSS-01, Rev. 0

SCOPE

This Transmission Material Standard Specification (TMSS) specifies the minimum technical requirements for design, engineering, manufacture, inspection, testing and performance of Transmission Line and Substation Latticed Steel Structures to be used on the transmission system of Saudi Electricity Company (SEC), Saudi Arabia.

2.0

CROSS REFERENCES This Material Standard Specification shall be read in conjunction with the latest revision of SEC General Specification No. 01-TMSS-01, titled "General Requirements for All Equipment/Materials" which shall be considered as an integral part of this TMSS. This TMSS shall also be read in conjunction with SEC Purchase Order or Contract Schedules for project, as applicable.

3.0

APPLICABLE CODES AND STANDARDS The latest revisions of the following Codes and Standards shall be applicable for the equipment/material covered in this TMSS. The vendor/manufacturer may propose equipment/material conforming to equivalent Industry Codes and Standards other than that quoted hereunder without jeopardizing the requirements of this TMSS, in which case he shall submit a copy of the proposed standards and shall submit a written proof that the proposed standards are equivalent in all significant respects to the standards specified. 3.1

ASTM A36M

Standard Specification for Carbon Structural Steel

3.2

ASTM A90M

Standard Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc Alloy Coatings

3.3

ASTM A123M

Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products

3.4

ASTM A143

Standard Practice for Safeguarding Against Embrittlement of Hot-Dip Galvanized Structural Steel Products and Procedure for Detecting Embrittlement

3.5

ASTM A153M

Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware

3.6

ASTM A239

Standard Practice for Locating the Thinnest Spot in a Zinc (Galvanized) Coating on Iron or Steel Articles

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4.0

20-TMSS-01, Rev. 0

3.7

ASTM A384

Standard Practice for Safeguarding Against Warpage and Distortion During Hot-Dip Galvanizing of Steel Assemblies

3.8

ASTM A385

Standard Practice for Providing High Quality Zinc Coatings (Hot-Dip)

3.9

ASTM A394

Standard Specification for Steel Transmission Tower Bolts, Zinc-Coated and Bare

3.10

ASTM F436

Standard Specification for Hardened Steel Washers

3.11

ASTM A563M

Standard Specification for Carbon and Alloy Steel Nuts

3.12

ASTM A572M

Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel

3.13

ASCE 10-97

ASCE Standard “Design of Latticed Steel Transmission Structures”

3.14

CRC

Guide to Design Criteria for Metal Compression Members

3.15

AISC, Part 5

Specification for Structural Steel Buildings

3.16

IEC 60652

Loading Tests on Overhead Line Towers

3.17

AWS D 1.1M

Structural Welding Code, Steel

3.18

SASO/SSA39

Mechanical Testing of Welding Joints

3.19

SASO/SSA 107

Tensile Testing of Steel

3.20

SASO/SSA 157

Charpy Method for Impact Test on Metals

DESIGN AND CONSTRUCTION REQUIREMENTS 4.1

Design 4.1.1

20TMSS01R0/MAA

Unless otherwise specified, all structures shall conform in all respects to the detailed requirements hereinafter stated. All structures and their components, in case of new structure designs, shall be designed in accordance with ASCE Standard 10-97 “Design of Latticed Steel Transmission Structures” and shall withstand without failure the stresses resulting from the factored loading combinations specified in TES-P-122.05, Part I, unless otherwise specified in the project Date of Approval: August 20, 2006

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20-TMSS-01, Rev. 0

technical specifications/scope of work. The structures shall be designed for all combinations of body and leg extensions including unequal leg extensions. 4.1.2

Types of structures and configuration requirements shall be as specified in the Data Schedule.

4.1.3

Minimum Thickness of Members The minimum thickness of the members shall be: a.

Leg Angles and compression members in cross-arms and ground wire peaks 6 mm

b.

Gusset plates

6 mm

c.

Connection plates

5 mm

d.

Other stress carrying members

5 mm

e.

Redundant members not carrying calculated stress 4 mm

f.

Stub Angles

8 mm

4.1.4

Minimum width of connected angles shall be 45 mm.

4.1.5

Thickness of stub angles shall be 2 millimeters more than the thickness of the corresponding leg extensions to which they will be connected.

4.1.6

Maximum Allowable Slenderness Ratios (L/r) a.

b.

20TMSS01R0/MAA

Compression members i.

Main Leg and cross-arm members

150

ii.

Other members carrying calculated Stress

200

iii

Redundant or secondary members without calculated stress

250

Tension-only members i

Hanger members (cross-arm)

375

ii.

Other tension members

500


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20-TMSS-01, Rev. 0

The determination of slenderness ratios (L/r) and the allowable compressive stresses shall be based on equations and factors given in the ASCE Standard 10-97. Where SEC standard tower structures are required, SEC certified fabrication drawings will be provided to the manufacturer/supplier. 4.2

Materials 4.2.1

Structural Steel a.

b.

4.2.2

20TMSS01R0/MAA

Except as noted, any combination of the following steels shall be used. The steel shall be made either by the open hearth, basic oxygen or electric furnace process and shall conform to the latest revision of the following ASTM Specifications: ASTM A36M

250 MPa (36,000 psi) minimum yield stress

ASTM A572M

345 MPa (50,000 psi) minimum yield stress, Grade 50

Structural steels as per standards other than those specified above may be used provided the proposed steels have characteristics at least equal to or better than those of the specified steels. Prior written approval shall be obtained from SEC. Acceptance of any proposed alternative steel will be at the discretion of SEC.

Bolts, Nuts, Palnuts and Washers a.

All bolts, nuts and washers shall be furnished by the Supplier and shall comply with the latest revisions of ASTM A394, ASTM A563M and ASTM F436 respectively. The diameter of the bolts shall not be less than 16 mm. Five percent (5%) extra bolts of each size (length) per type per structure shall be furnished.

b.

The galvanizing of bolts, nuts, washers and palnuts shall be in accordance with ASTM A153M. Bolts shall be galvanized in such a manner that the zinc in the thread will not interfere with the application of nuts. Re-threading of bolts after galvanizing shall not be permitted.

c.

Bolts shall be of such length so as to pass entirely through the nuts with a minimum projection of three (3) full threads and a maximum projection of 20 mm. No more than 3 mm of the threaded portion of the bolt shall be inside the structural members. The nuts shall fit the bolts snugly. Date of Approval: August 20, 2006

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4.2.3

20-TMSS-01, Rev. 0

d.

The Supplier shall furnish one type of connection bolts and nuts for tangent/suspension type structures. However, for angle/dead-end type structures, two types of connection bolts may be used. All bolts shall be provided with hot-dip galvanized steel palnuts.

e.

Step-bolts shall be Φ 16 mm x 180 mm or Φ 20 mm x 180 mm, as specified in the data schedule and shall conform to the latest revision of ASTM A394. Each bolt shall be supplied with two (2) nuts but without washers and palnuts.

Structure Member Galvanizing a.

Structural steel members, including the stub angles, shall be hotdip galvanized after fabrication in accordance with the requirements of ASTM A123M except that the minimum coating thickness shall be as follows: i.

130 microns, equivalent to 915 g/m 2 for all structures located in the coastal area

ii.

86 microns, equivalent to 610 g/m2 for all structures located in the inland area

The requred zinc coating thickness shall be specified in the Data Schedule. Uniformity of coating shall be determined by Preece Test per ASTM A239 or by Weight of Coating Test per ASTM A90M. The limits on uniformity shall be: Preece Test: One minute dips

9 minimum (for 915 g/m²) 6 minimum (for 610 g/m²)

Weight of Coating Test: Minimum thickness as average in 3300 mm 2 area

20TMSS01R0/MAA

130 µm (for 915 g/m²) 86 µm (for 610 g/m²)

b.

Special coatings, such as painting or other color coating agents may be applied after galvanizing on the structures located in the coastal area if specified in the Data Schedule and shall be mutually agreed upon between the Supplier and SEC prior to their use.

c.

Stub angles shall be hot-dip galvanized over their entire length. Date of Approval: August 20, 2006

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4.3

20-TMSS-01, Rev. 0

d.

All galvanizing practices shall be done in accordance with the recommendations of ASTM A143, ASTM A384, and ASTM A385.

e.

Embrittlement tests shall be conducted on structural steel of ASTM A572M as recommended in ASTM A143.

Detailing 4.3.1

Drawings Structure detail drawings shall consist of outline drawings, erection drawings, shop detail drawings and bill of materials. The outline drawings shall show the complete design information, dimensions and member sizes. The outline drawings shall also include the following information related to the design of structures: a.

Description of phase conductors, overhead ground wires/OPGW, controlling sag and tension conditions, etc.

b.

Design spans (ruling span, wind and weight spans)

c.

Clearance diagrams and loading tree diagrams, etc. (may be on separate drawings)

d.

Maximum foundation reactions (along the vertical and along the leg slope) with and without structure overload capacity factors

Erection drawings shall show the complete assembly of the structure indicating clearly the positioning of the members. Each member shall be piece-marked and the number and lengths of bolts shall be given for each connection. Shop details may be shown either by assembled sections (in place) or piece by piece (knocked down). 4.3.2

Shop Detail Drawings Shop detail drawings shall be reviewed and approved by SEC regarding compliance with this specification and the strength requirements of the design. The review and approval of the shop detail drawings only includes the strength of connections.

4.3.3

Connections Usual detailing practice is to connect members directly to each other with minimum eccentricity. Specific joint details are required and shall be shown on the design drawings.

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4.3.4

20-TMSS-01, Rev. 0

Bolt Spacing Minimum bolt spacing and edge distances shall not be underrun by mill or standard fabrication tolerances. End distances, edge distances, and center-to-center hole spacing shall include provisions for mill and fabrication tolerances to ensure that minimum dimensions are provided in the fabricated members.

4.3.5

Materials Detail drawings shall clearly specify member and connection materials by ASTM specification and grade designation.

4.3.6

Tension-Only Members Tension-only members shall be detailed sufficiently short to provide draw. Shortness for the required draw must consider the length and size of the members. To facilitate erection, these members should have at least two bolts on each end. Members 4.50 meters in length, or less, shall be detailed 3 mm short. Members more than 4.50 meters long shall be detailed 3 mm short, plus 1.5 mm for each additional 3.00 meters or fraction thereof. If such members are spliced, the draw should provide the slippage at the splice.

4.3.7

Shop Assembly Before starting mass fabrication of structures, one structure of each type including all combinations of body and leg extensions shall be shop-assembled and preferably vertically erected on a suitable foundation bed to assure proper fit of all parts as finally manufactured. Shop assembly shall be witnessed by SEC/SEC approved independent inspection agency. Following shall be kept in view during shop assembly:

20TMSS01R0/MAA

a.

Each member shall be checked carefully while assembling the structure and conflicts, if any, between actual assembly work and the drawings shall be rectified and shown on the detailed drawings.

b.

Length of each member, position of holes and interface with other members shall be checked accurately for proper fitness.

c.

Quantity of each member and bolts shall be checked and verified with the bill of materials and the drawings shall be corrected, if necessary.

d.

Eventual modifications shall be examined and performed on the assembled structure, if necessary, without modifying the functionality of the structure. Date of Approval: August 20, 2006

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e.

20-TMSS-01, Rev. 0

Drawings, bill of materials, sizes of bolts and fillers, etc., shall be put up-to-date accordingly in all details before starting mass fabrication.

All changes/modifications incorporated in the drawings shall be brought to the notice of SEC with corrected final copies of the drawings for approval. The manufacturer shall also submit the details of all the changes/modifications carried out. 4.3.8

4.4

Other Considerations a.

All dimensions on detail drawings shall be shown in SI units with dimensional accuracy to the nearest 1.5 mm.

b.

Provision for attachment of hot line maintenance equipment, danger/number signs, circuit designation/phase identification signs, aerial patrol signs and grounding connections or other construction/ maintenance aids shall also be included in the detail drawings.

c.

The details of like members in all four faces of square base towers shall be made the same as far as practicable.

d.

Provision for fixing anti-climbing devices, their location and details shall be included in the detail drawings.

Fabrication 4.4.1

Fabrication shall be done in accordance with this Specification and the latest edition of the AISC Manual of Steel Construction, Part 5, Specification for Structural Steel Buildings. Cutting of steel members by power saw or shearing is preferred.

4.4.2

The slope of surfaces of bolted parts in contact with the bolt head and nut shall not exceed 1:20 with respect to a plane normal to the bolt axis. Bolted parts shall fit solidly together when assembled and shall not be separated by gaskets or any other interposed compressible material.

4.4.3

Splices of leg angle members shall be butt splices, except that lap splices may be used if the lower angle is larger than the upper angle and the thickness of the larger angle is not more than 22 mm.

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20-TMSS-01, Rev. 0

a.

Lap splices, located on battered legs below the tower waist, shall generally have the upper section lapped on outside of lower section unless difference in section sizes makes it impracticable.

b.

The inside angle of lap splices and stub legs shall be ground at the heel to fit the fillet of the outside angle. A gauge clearance of 2 mm shall be provided between splice faces to account for the galvanizing coating thickness. A clearance of about 3 mm is optional for lap splices of 200 mm by 200 mm angles and greater.

c.

Leg splice points shall normally be above, and as close as is practical to brace points.

4.4.4

Connections of members shall be detailed in such a manner as to minimize eccentricity. All parts shall be accessible for inspection and cleaning.

4.4.5

Where gusset plates are used, web members designed for compression should, as far as practical, be connected to the main members with at least one bolt. Diagonal (web) members designed for tension only may be connected entirely by a gusset to avoid the use of fillers. Where fillers are required at two or more adjacent holes, a single plate filler shall be used instead of ring fillers.

4.4.6

When bolts carrying computed stress pass through fillers thicker than 6 mm, the fillers shall be extended beyond the spliced material and the filler extension shall be secured by enough bolts to distribute the total stress in the members less the stress carried by bolts connecting to main members directly, uniformly over the combined section of the member and the filler, or an equivalent number of bolts shall be included in the connection.

4.4.7

Detailed requirements for conductor and overhead ground wire attachment points shall be provided on the Structure Erection Drawings. Hangers, when required and unless otherwise shown on the drawings, shall be free to move in the longitudinal direction of the transmission line and rigid in the direction transverse to the line. Holes for moving parts shall be drilled and cambered unless otherwise specified. Such holes shall have adequate bearing area and in addition to the normal edge distance shall have an extra 6 mm edge distance to provide for wear. The thickness of plates for conductor and ground wire attachments shall not be less than 16 mm.

4.4.8

Redundant bracings shall be required between the upper and lower chords of cross-arms when diagonal braces are used between the two lower chords of an arm.

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20-TMSS-01, Rev. 0

4.4.9

Structural materials shall be straight (within AISC tolerance) before being laid out or worked in any manner. Straightening will not be permitted.

4.4.10

Shearing and cutting shall be performed carefully and all portions, which will be exposed to view after completion, shall be neatly finished. All burrs shall be removed. Ends shall be squared within 1.5 degrees.

4.4.11

Copes and re-entrant cuts shall be filleted before cutting.

4.4.12

All bending shall be done in such a manner that the full section and member length will be maintained within 5 percent reduction and that the physical properties of the material will not be impaired. Bending shall be made across the grain structure of the material.

4.4.13

a.

Members bent hot shall be heated in a non-oxidizing flame over a sufficient area to prevent excessive deformation.

b.

Hot bends shall be nested for slow cooling in air. In cases where bends are near splices, the upset metal shall be forged smooth for full bearing on the contact surface.

c.

All bends shall be finished free from waves and folds. The practice of cutting out sections and welding to facilitate the bending of bent members will not be permitted.

Punching shall be done before galvanizing in such a manner as to produce cylindrical holes normal to the plane of the material. The holes shall not be out of round, or taper from the top to bottom in excess of 1.5 mm. The punchers and dies shall be maintained in such condition as to produce clean holes, free from burrs, folds depressed or upset edges. Bolt holes shall be 1.5 mm larger than the nominal diameter of the bolts. The dies for all sub-punched holes, and the drill for sub-drilled holes, shall be at least 1.5 mm smaller than the nominal diameter of the bolts. Drifting to enlarge holes shall not be permitted.

4.4.14

20TMSS01R0/MAA

Welding of structure members, filling or plugging of defective parts and mispunched holes shall not be permitted in tower fabrication. When holes are mispunched so that the net section of a member is decreased, the member shall be discarded. However, if welding cannot be avoided and is required in certain structure components, such as for rigging/attachment plates, prior written approval from SEC shall be obtained. In such cases welding procedures shall Date of Approval: August 20, 2006

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20-TMSS-01, Rev. 0

comply with ANSI/AWS D1.1M and SEC General Welding Criteria TES-W-1. Special care shall be taken regarding seal welds to assure proper galvanizing and to avoid acid “bleeding” at pockets in structural assemblies. 4.4.15

All holes in materials over 20 mm in thickness shall either be drilled or sub-drilled and reamed. For high tensile steels (yield point equal or greater than 345 MPa) holes shall be directly drilled at the definitive diameter or punched and reamed out. The difference between the punched and reamed diameter shall not be more than 4 mm.

4.4.16

All angles connected by one leg only shall have the gauge line as close to the back of the angle as practicable.

4.4.17

All compression members that have two angles back-to-back shall have stitch bolts.

4.4.18

Cross bracing angles shall not be coped where they cross each other. If the connection cannot be made without cutting, both angles shall be cut and a gusset plate shall be used to connect them at their intersection.

4.4.19

Bracing angles, used in tension only, shall have 1.5 mm draw for every 3 meters of length and an additional 1.5 mm draw for each extra joint.

4.4.20

Materials shall be heated to bend, except plates, which may be bent cold.

4.4.21

When a material is bent, all holes near the bend shall be punched after the bend is made.

4.4.22

Cutting the outstanding legs of angles or flanges of channels and then welding at the bend point shall not be permitted.

4.4.23

Unless otherwise specified, all connections shall be bolted and all members carrying calculated stresses shall be connected by at least two bolts. Secondary redundant members may be connected by one bolt, which shall be placed on the inner gauge line.

4.4.24

Splices in corner legs of structures or extensions shall be located immediately above horizontal members, if possible, or above diagonal brace connections. The holes for splices shall be staggered to give maximum net cross-sectionional area.

4.4.25

Structure members shall have the flat surfaces up where practicable. There shall be no pockets or depressions, which will retain water. Unavoidable depressions shall have drain holes. In general, horizontal angles shall be placed with the outstanding legs on top.

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4.4.26

4.5

5.0

20-TMSS-01, Rev. 0

Diagonally opposite legs of the structures and extensions shall be punched for step bolts. The holes shall be spaced on the inner gauge line of alternate faces and shall be 400 mm on centers. The step bolts shall be placed on the two diagonally opposite legs starting 3000 mm above the top of concrete foundation. The step bolt holes shall be spaced so that any combination of assembled structure body; body extension and leg extension shall result in 400 mm spacing of entire step bolt ladder. Holes for removable step bolts below the anticlimbing device shall be provided at a maximum 400 mm spacing to a point 1000 mm above the top of concrete foundation.

Markings 4.5.1

Each structure member shall have a mark for structure type and a number conforming to the piece-mark on the erection drawings stamped with a metal die. For galvanized materials, these marks shall be stamped prior to galvanizing. Marks shall be a minimum of 12.7 mm (1/2 inch) high. The marks shall be placed, preferably, near one end in the same relative position on each member, so as to be easily seen after assembly of structure.

4.5.2

High strength steel members shall include a suffix “H”, on the piecemark, whereas mild steel members shall not have any suffix.

4.5.3

As an option (if specified in the SOW/TS and requested in the data schedule), each structure member shall be stamped with a two letters mark identifying the name of the transmission line between two substations, for which the structure material is being manufactured.

4.5.4

All bolt heads shall have raised marks of grade of steel.

INSPECTION AND TESTING In addition to the requirements specified in 01-TMSS-01, the following shall be fulfilled: The Supplier shall make adequate tests and inspections to determine the conformity of materials furnished under this Specification with the requirements invoked. SEC or its designated representative will conduct acceptance inspection and witness testing at the manufacturer's plant. 5.1

Inspection Requirements 5.1.1

20TMSS01R0/MAA

Inspection shall cover material certification, material handling, cutting and piece-mark identification procedures, bending, nondestructive testing, galvanizing, fit-up requirements, dimensional check and bundling for shipment. Date of Approval: August 20, 2006

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5.2

20-TMSS-01, Rev. 0

5.1.2

Visual inspection shall include checks for satisfactory workmanship, materials, and freedom from surface defects.

5.1.3

SEC designated representative shall have free access at all times while work is being carried on, to all parts of the Supplier's plant which concerns the work.

5.1.4

Inspection may be made during all stages of manufacturing, testing and shipping. Inspection may be at the point of shipment or delivery or construction site, etc., at SEC’s option. However, inspection and acceptance shall not relieve the Supplier of his responsibility for conformance with this specification.

Testing Requirements Mill test reports of materials shall be furnished to SEC prior to start of FullScale Structure Loading Test and/or full-scale fabrication. 5.2.1

Shop Fit Tests The Supplier, at his expense, shall fabricate per approved detail drawings and assemble in accordance with approved erection drawings the designated structure type components. The structure bodies shall be assembled in sections and shall demonstrate that each section fits the adjacent section, that the leg extensions fit all body extensions and that Supplier shall provide to SEC a certificate of the Proof of Fit Test for each structure type, all associated body and leg extensions, and stub angles that have been assembled satisfactorily.

5.2.2

Proof Tests The latticed steel structures shall be proof tested in accordance with this Specification. The proof test will verify the adequacy of the members and their connections to withstand the static design loads specified for that structure as an individual entity under controlled conditions.

5.2.3

Full-Scale Loading Tests When SEC desires full-scale loading tests, it shall be as stated in the Data Schedule. The Supplier shall then include in his proposal, as a separate item, the cost of the tests. For full-scale structure loading tests, each of the structures designated shall have the same steel members as specified in the design, fabricated in accordance with approved detailed drawings, and assembled in accordance with approved erection drawings. The

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20-TMSS-01, Rev. 0


structure shall be tested on a rigid foundation at SEC approved tower test facility in a manner that will best simulate the design conditions. The tests shall be performed on a galvanized structure with the longest body and leg extensions. The rigid foundation at the test facility shall not cause any movement of the structure. a.

Rigging for Test The Supplier shall submit for approval by SEC, diagrams showing the proposed scheme for applying and measuring loads and determining deflections of critical points.

b.

All load measuring devices shall be calibrated in the presence of SEC designated representative or be certified by a qualified independent testing agency immediately before and after testing.

c.

Test Loads Test loads shall be the same as the factored design loads indicated on the design drawings and the test program approved by SEC. Separate tests may be made for each combination of loading shown on the approved design drawings, but shall be made for each loading, which controls the design of a member: i.

Loads shall be applied in five steps of 50%, 75%, 90%, 95% and 100% of the specified design-factored loads. After each step, except for 100% load step, sufficient hold time (at least three minutes) shall be allowed for reading deflections and to permit inspectors observing the test to check for signs of structural distress. The 100% load for each loading combination shall be held for five minutes. Loads within any loading combination may generally be applied in any sequence provided all factored loads in a combination are applied simultaneously.

ii.

For each load level, the applied load measurements shall be considered acceptable if they are within the l imits given below: Load level (%)

Acceptable range (%)

50 75 90 95 100

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49 to 51 74 to 76 89 to 91 94 to 96 100 to 102

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20-TMSS-01, Rev. 0

The applied loads within the hold time shall be adjusted to bring into the acceptable limits. iii.

Each structure to be tested shall withstand each factored loading combination specified without failure. Failure shall be defined as the inability of steel structure to withstand the applied loads within the hold time for each step or the application of additional loads such as: •

Any noticeable permanent distortion of a member, or elongation of bolt holes of more than 1 mm

•

Any shear failure in bolts

•

Any member failure in compression or bending

The following shall not be considered as failures: •

•

•

Residual bowing of members designed for tension only; Ovalization of no more than one-half of the holes in a connection; and Slight deformation of no more than one-half of the bolts in a connection.

In case of failure, test reports of failed members shall be furnished to SEC and the design of the failed members shall be modified. These modifications must be approved by SEC before retesting for the loading condition, which caused failure and for all untested combinations until the structure has been found satisfactory. Retesting of successfully completed tests is not required. iv.

20TMSS01R0/MAA

Load lines shall be attached to the load points on steel structures in a manner that simulates the in-service load application as much as possible. The attachment hardware for the test shall have the same degree of movement as in the in-service hardware. If the applied loads are not measured at the point of application and sheaves (only roller bearing type permitted) are to be located between point of load application and the load measuring device, then an additional 5% load may be added to all applied loads to offset friction drag in the rigging. This requirement can be adjusted where the Supplier can verify the actual friction drag.


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d.

5.2.4

20-TMSS-01, Rev. 0

v.

Where the Vee-strings or other multi-leg insulator assemblies are part of the structure design, test loads shall be applied at the conductor attachment points. The Veestrings shall be simulated using a series of straps to ensure complete transverse and vertical articulation, (i.e., the linkage shall not be capable of withstanding compressive forces).

vi.

Wind loads on structure body shall be applied at panel points.

Destruction Tests i.

Prototype structures of each type (as specified in the data schedule) shall be tested to destruction. The destruction tests shall be made after satisfactory completion of all the required tests. Generally, the loading for destruction tests shall be made by increasing the transverse loads in increments to failure.

ii.

Each member of the structure fabricated for testing purposes shall be punched as “TEST”. The Supplier shall not supply any of the undamaged materials, which were part of the tested structures against the delivery requirements. All structure test materials shall be scrapped. All structure material after destruction testing shall remain the property of the Supplier.

iii.

Upon completion of testing, disassembly of the structure shall include inspection of all members for any evidence of excessive permanent set, shear failure of bolts, or member failure in bearing not determined during the fullscale testing program.

iv.

All design and detailing defects determined during the tests or during the disassembly shall be considered as having incurred and shall be corrected on all structures of that type and also other types not tested having similar configuration, details or design concept.

Deflections (During Structure Tests) Structure deflections under load shall be measured and recorded to provide at least the following information: a.

20TMSS01R0/MAA

Longitudinal and transverse deflections at ground wire peaks, ends of conductor cross-arms, center of structure bridge (when applicable) and at structure waist


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5.2.5

20-TMSS-01, Rev. 0

b.

Horizontal rotation of the structure at the bridge and waist levels

c.

Deflection readings shall be recorded for the "before-load", "load-on", and "load-off" conditions as well as during intermediate holds during loading. All deflections shall be referenced to common base readings, such as the initial positions, taken before any test loads are applied.

d.

SEC reserves the right to request modification of the structure design after review of the structure deflection tests results.

Test Reports Within forty five (45) days after completion of the structure loading tests, the Supplier shall furnish a full and comprehensive report (four copies) of each structure test, which shall include detailed diagrams and tabulations showing values and methods of load application and deflection records of each load test, photographs of test set-up and description (with photographs) of all failures, if any. The report shall include mill test reports of the materials used and the results of any tensile tests of specimens cut from any members, which failed during the testing program. Particular emphasis shall be placed on the determination of the yield point of the material.

5.2.6

Test Acceptance The Supplier, upon receipt of written acceptance from SEC for the satisfactory performance of the structure loading tests, may start fabrication of the structures except those members requiring modifications. Fabrication of these members shall not commence until revised detail and erection drawings have been reviewed and approved by SEC.

6.0

PACKING AND SHIPPING In addition to the packing and shipping requirements specified in 01-TMSS-01, the following shall be fulfilled: 6.1

All materials, prior to shipping, shall be dipped in a suitable solution such as sodium bichromate to protect the galvanizing from “White Rust” corrosion during transit. Full details of the treatment proposed shall be submitted to SEC for approval. The effectiveness of the treatment shall be verified in accordance with ASTM B201.

6.2

All parts designed for bolting together shall be shipped unassembled. The parts for each structure shall be bundled together in one or more bundles and each bundle shall be tagged indicating the structure type and height. In no case

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shall parts of two or more structures be bundled together. When any one structure involves more than one bundle, all bundles for any one structure shall be shipped in the same transporting unit.

7.0

6.3

Small parts, such as U-bolts, structure bolts, ring fillers, nuts, palnuts and clip angles, shall be shipped in bulk with like items packaged separately, and with none weighing more than 136 kilograms. Steel nuts shall be oil treated and run up on bolt to fill all threads. Each box or keg shall be clearly marked with a description and quantity of its contents. The marking shall be waterproof. Shipment of bolts and/or other small items in bags is not allowed unless the bag is then placed in a sealed box or keg. Kegs or boxes shall be securely fastened with galvanized, or other suitable straps to wooden pallets for shipment.

6.4

SEC shall specify the anticipated number and locations of delivery points.

6.5

Prior to shipment, three (3) copies of a master bundling list indicating the contents of each bundle, box, keg and pallet shall be furnished by the Supplier as well as a shipping list for each delivery point.

6.6

In cases where bundling is by structure components, the bundling list shall also state the number of bundles, boxes or kegs necessary to assemble each complete structure part.

6.7

SEC or designated representative shall unload the individual bundles upon delivery at the designated delivery points and sign a receipt for them.

6.8

When truck shipment is authorized by SEC, all written shipping instructions furnished shall be complied with by the Supplier. In general, the Supplier shall provide notification at least 48 hours in advance of delivery to assure that unloading personnel and equipment will be available.

6.9

Reasonable care shall be exercised in the bundling and shipment of steel. Any expense incurred due to the careless bundling or shipment of steel shall be considered as a legitimate back charge against the Supplier.

DOCUMENTATION REQUIREMENTS 7.1

General In addition to documentations specified in 01-TMSS-01, the following information shall be supplied by the Manufacturer/Supplier: 7.1.1

Manufacturing Schedule and Progress Reports a.

20TMSS01R0/MAA

The Supplier shall prepare a detailed Schedule and submit it with the Data Schedule of this specification. Time allocations, milestones, and test dates shall be included. Date of Approval: August 20, 2006

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b.

7.1.2

7.1.3

20-TMSS-01, Rev. 0

The Supplier shall furnish three (3) copies of monthly progress reports showing the status of manufactured component parts of structures, expected test date of prototype structures, quantity of ready for shipment/delivery and assembly structure units for SEC verification that project milestone will be met.

Design information and drawings to be supplied with the proposal for review: a.

Calculated shipping weight of each structure, excluding stub angles, leg extensions, body extensions, and bolts and nuts

b.

Calculated shipping weight of stub angles, leg extensions, body extensions, and bolts and nuts

c.

Factored foundation reactions (including structure overload capacity factors)

d.

Type of material of components (ASTM designation, if applicable)

e.

Description of structure members, including thicknesses, lengths, and method of connections

f.

The Supplier shall submit with his proposal four (4) prints of the preliminary design drawings for each structure type. These design drawings shall show one-line drawings of each structure with calculated stresses in all members and size of each member shown thereon. These drawings shall also give the maximum unit stresses, design formula and design loadings used in the design of the structure.

Documentation to be supplied to SEC for review and acceptance: Final design calculations for tower members, stub angles and other appurtenances, including connections on the following:

20TMSS01R0/MAA

a.

For each loading case, the total shear and axial forces, moments, stresses, section moduli and deflections

b.

For the critical loading case, including foundation movement, total shear and axial forces, moments, stresses, section moduli and deflections, and also the bolt stresses in member connections

c.

After acceptance of a proposal, the successful Supplier shall submit within ten (10) days to SEC a tabulated list of all drawings to be used within the agreed time frame, three (3) Date of Approval: August 20, 2006

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20-TMSS-01, Rev. 0

prints of erection drawings and three (3) prints of each shop drawing. Within four (4) weeks after receipt of acceptance of designs, the Supplier shall submit for acceptance, the foundation setting drawings for the types of foundation specified on the Structure Conceptual Drawings. One set of the above drawings will be returned to the Supplier with indication of acceptance or with comments and/or correction. Where a correction is required, or unless otherwise specified, three (3) sets of revised prints, plainly marked "Revised" and dated, shall be sent to SEC for review and comments. All design and detail drawings shall be accepted by SEC in writing before fabrication. The Supplier shall be responsible for the correctness of dimensions and details on the working drawings and the acceptance of the detail drawings by SEC will not relieve the Supplier of this responsibility. In the event of any errors in detailing are found in the fabrication or erection of the structures, the Supplier shall correct and revise the drawings and furnish new drawings without cost to SEC. 7.1.4

Final Drawing Information a.

An erection drawing and drawings for each type of structure shall be submitted by the Supplier. These drawings shall show the identification marks, location of each member, size, number and location of bolts and a complete list of parts, their identification marks and dimensions. These drawings shall also show total weight per structure, by extension, by leg, and by body.

b.

Supplier shall furnish to SEC all final design drawings, shop detail drawings, erection drawings, and stub setting drawings of each structure type in original or Mylar drawings as well as in digital format on a CD compatible with Intergraph (Microstation) CADD System (digital microstation *DGN format). Reproduced prints from the above tracings shall be clear and legible. SEC reserves the right to retain the drawings permanently and at its discretion may be used for future design fabrication and erection of similar or identical structures. Drawings of stub setting drawings shall be sent at least four weeks, or an agreed time frame, prior to initial shipment of the stub angles. Shop detail drawings shall be sent at the time steel fabrication is started, or an agreed time frame. Erection

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drawings shall be sent at least four weeks or an agreed time frame, prior to initial shipment of steel towers. c.

7.1.5

7.2

Design calculations shall be submitted in Adobe Portable Document Format (PDF) files in a CD. These shall also include structure outline drawings.

Test Reports a.

Certified mill test reports for all materials

b.

Certified welding reports for each structure, if any

c.

Test reports on coating thickness

d.

Report of all structure testing, when required, including photos, diagrams, loading trees, etc.

Drawings 7.2.1

General a.

All design drawings shall be to SEC drawing standard sizes: A = 711 mm x 1016 mm B = 508 mm x 711 mm C = 356 mm x 508 mm D = 279 mm x 432 mm E = 211 mm x 297 mm

7.2.2

b.

Detail and erection drawings shall be on size 711 mm x 1016 mm sheets. No drawing shall contain design details of more than one (1) structure type.

c.

All design drawings to be provided under Turnkey Contract shall conform to the latest revision of SEC Engineering Drawing Standard SEEDS-II.

Types of Drawings Required a.

Design drawings shall consist of, but not limited to, the following: i. ii. iii.

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Structure outline and dimensions Structure loading trees Structure and Foundation design information/calculations


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iv

Structure details: • •

b.

Sizes of main, secondary and redundant members Distances between joints/connections

Shop Detail Drawings shall show i. ii. iii. iv. v. vi.

Each panel All parts or pieces with identification marks All information required for fabrication including, but not limited to, dimensions for cutting and punching All holes, hole sizes, batters and distances between each Enlarged details where necessary to provide clarity A bill of materials for all materials shown on the drawing, including: • • •

c.

20-TMSS-01, Rev. 0

The mark designating the part or piece A description of each part Number of pieces required

Erection Drawings Basic Structure Erection Drawings shall show: i.

The position, assembly number and part marks of each member, including cross-arms, shall be shown on a single sheet, if possible

ii.

Size and number of bolts required for each connection

iii.

A bill of materials showing: • • • • •

iv.

d.

Structure Body Extension and Leg Extension Erection Drawings shall show the same information required for the basic structure (items i to iii above). Additional sheets may be used as required.

Stub Angle Drawings shall show i. ii. iii.

20TMSS01R0/MAA

Number of parts required Description of parts including size and weight Mark used for each part Complete bolt list showing size and length Cross-reference to appropriate shop detail drawings

Stub setting dimensions, angles, and batter (in mm per cm of rise) Part marks and position of each Bend point or bend line Date of Approval: August 20, 2006

PAGE NO. 24 OF 30


iv.

A bill of materials showing: • • • • •

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20-TMSS-01, Rev. 0

Number of parts required Description of parts including size and weight Mark used for each part Complete bolt list showing size and length Cross-reference to appropriate shop detail drawings


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20-TMSS-01, Rev. 0


8.0

DATA SCHEDULE

LATTICED STEEL STRUCTURES SEC Enquiry No.

Date:

SEC Purchase Order No. or Contract No.

Date:

SEC PTS No./Project Title with J.O. No. REFERENCE SECTION NO.

3.0

DESCRIPTION

'A'

'B'

'C'

APPLICABLE CODES AND STANDARDS Applicable Industry Standards

4.0

DESIGN AND CONSTRUCTION REQUIREMENTS

4.1.2.

Line Voltage 69kV/110kV/115kV/132kV/230kV/380kV Structure Types Tangent/Suspension Small Angle Light Angle Medium Angle Heavy Angle Dead-end

'A'- SEC SPECIFIED DATA/PARAMETERS 'B'- BIDDER/SUPPLIER/VENDOR/CONTRACTOR PROPOSED DATA/PARAMETERS 'C'- REMARKS SUPPORTING THE PROPOSED DEVIATION IN COLUMN 'B' (*)- DATA/PARAMETERS TO BE PROVIDED/PROPOSED BY THE BIDDER/SUPPLIER/ VENDOR/CONTRACTOR IN COLUMN 'B'.

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8.0

DATA SCHEDULE

LATTICED STEEL STRUCTURES REFERENCE SECTION NO.

DESCRIPTION

'A'

'B'

'C'

Transposition Gantry Structure Configuration (single/double circuit, vertical/horizontal/delta) Conductor Bundle (single/twin/quad) Number of Ground Wires (one/two) Height of Basic Structure Body, meters

*

Complete Structure (maximum), meters

*

Complete Structure (minimum), meters

*

Structure Base Width, meters

*

Spacing between Ground Wire peak and upper Cross-arm, meters

*

Spacing between upper Cross-arm and middle Cross-arm, meters

*

Spacing between middle Cross-arm and bottom Cross-arm, meters

*

Weight of Structure Parts in kg Basic Structure Body

*

Maximum Body Extension

*

Maximum Single Leg Extension

*

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20-TMSS-01, Rev. 0


8.0

DATA SCHEDULE

LATTICED STEEL STRUCTURES REFERENCE SECTION NO. 4.2

DESCRIPTION

Material Specification (angles and plates)

*

Material Specification (bolts, nuts, palnuts and washers)

*

'C'

130/86 µm

Material Specification (angles and plates)

*

Galvanizing thickness for nuts, bolts and washers

53 µm

Painting after Galvanizing

Yes/No

Step bolt diameter

5.2.3

'B'

Materials

Galvanizing thickness for members (angle sections)

4.5

'A'

16/20mm

Markings Each member to be marked with two letters identifying the name of transmission line between two substations (Optional)

Yes/No

Full-Scale Loading Test

Yes/No

Type of Structure Destruction Testing

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Yes/No


PAGE NO. 28 OF 30

20-TMSS-01, Rev. 0


8.0

DATA SCHEDULE

LATTICED STEEL STRUCTURES

REFERENCE SECTION NO.

7.1.2

DESCRIPTION

'A'

'B'

'C'

Foundation Reactions, kN Factored (maximum) Compression (Vertical)

*

Uplift (Vertical)

*

Lateral Shear

*

Longitudinal Shear

*

Un-factored (maximum) Compression (Vertical)

*

Uplift (Vertical)

*

Lateral Shear

*

Longitudinal Shear

*

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20-TMSS-01, Rev. 0


8.0

DATA SCHEDULE

LATTICED STEEL STRUCTURES

A.

ADDITIONAL TECHNICAL INFORMATION OR FEATURES TO BE FURNISHED BY SEC:

B.

ADDITIONAL SUPPLEMENTARY DATA OR BIDDER/VENDOR/SUPPLIER/CONTRACTOR:

B.

OTHER PARTICULARS TO BE FILLED UP BY BIDDER/VENDOR/SUPPLIER/ CONTRACTOR:

FEATURES

Actual Manufacturer of Equipment/Material

PROPOSED

BY

Vendor/Supplier/ Contractor

Name of the Company Location and address

Name and Signature of authorized representative and date

Official Seal/Stamp of the Company & Date

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20-TMSS-01-R0

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