Introduction
PSD is considering to purchase and erect Steel Structure Telecommunication Towers as per the attached Annex
1. TOWER SHALL MEET AND COMPLY WITH THE FOLLOWING STANDARDS REQUIREMENTS :
- Towers shall meet and comply with all relevant International Standards including but not limited to EIN11A-222-E, F Or equivalent European Standards.
- Tower shall be designed by or under the direct supervision of a registered profession & engineer, specifically experienced in the design of microwave towers. All design and analysis computations and installation drawings shall be certified and stamped by a licensed Professional Engineer.
- Required Tower shall be, angled, galvanized, self-supporting type and require
low maintenance, low maintenance. - The Contractor shall employ a quality control program that will ensure that
engineering, fabrication, erection and relevant activities meet the requirements
of this specification. - Contractor is required to provide complete erected Tower and also complete
plans, assembly drawings which summarize the Tower components and
foundation specifications, other documentation showing the necessary
marking and details for the proper assembly and installation of the material
including the design yield strength of the structural members and the grade of
Structural bolts which to be used. - Manufacturer is required to fill in and sign the compliance list provided with
tender, the compliance list will be considered as a vital part of project
documents. - All documents relevant to this project shall be printed in English Language.
- The life cycle of the Tower shall be 50 years minimum.
2. GENERAL REQUIREMENTS :
- All hardware must be hot dipped galvanized in accordance with the Provisions
of ASTM A-153 or equivalent. - Wind load, to be designed for a basic wind speed of 160 kilometers Per hour.
- Antenna loading: As per Annex 1.
- Tower shall be designed, as defined in EI4AJTIA- 222. Ice load shall be
included on the Tower structure, antennas’ appurtenances, wave guides and
transmission lines. - Tower sections shall be of bolted construction to permit in- service
replacement of members. Shop welding shall be kept to a minimum and field
welding is not permitted. - Twist angle permitted shall be less than 0.25 degree.
- All K-braced or reversed K-braced sections shall be designed to include a
structurally stable configuration of internal bracing at the midpoint of
horizontal members. - Connections shall be detailed and designed to minimize stresses attributable to
eccentricity - High strength bolts confirming to relevant international standards (e.g. ASTM
A-325 or A -449) shall be used in all calculated load carrying connections All
threaded fasteners shall be of adequate length that a minimum of two threads
shall protrude beyond the nut or locking device when the nut is properly
tensioned. - Space of 3 mm or greater between parallel or crossing members shall be filled
with single thickness plates or ring fills. Stacked washers shell not be used for
any reason for this purpose. - Hardened flat washers shall be provided for all oversized of slotted holes.
- Anchor bolts shall be designed such that their projection above the concrete
allows for one leveling nut below and two full-sized nuts above the base plate
of the tower. - Under no circumstances shall ‘dissimilar metals’ be used in contact with one
another.
3. DESIGN CALCULATIONS AND DRAWINGS
- Three complete sets of the Tower drawings, one set of the tower grounding
system and one set of design calculations for each tower shall be furnished to
PSD in print and electronic form All submittals must bear a Professional
Engineer’s stamp. - The Contractor shall submit structural calculations, foundation, and erection
drawings for each Tower site location. Complete structural calculations are
required covering all parts of the structures and all relevant items. Actual
stresses and corresponding allowable stresses shall be listed for the vertical,
diagonal and, girt members of the tower twist, sway, and displacement
calculations shall be Made and identified for each microwave antenna. When
computer printouts form a portion of the calculations, the Contractor shall
include sufficient information to allow an independent engineer to thoroughly
review the design. - The drawings include the station name, tower height, manufacturer’s name,
manufacturer’s model number, antenna path azimuths, and elevation and plan
views of the tower indicating the tower orientation In addition, the Contractor
shall furnish section assembly drawings showing all tower members with their
part numbers, splice plates, ladder mounting details, bolt sizes and types, and
any other Information necessary to identify each Tower component. - Grounding system Drawing shall provide detailed information about the
grounding system, showing lengths, elements dimensions, elements
connectivity, quantities, layout and method of interconnection with shelter
grounding system. All pertinent requirements of above sections of this specification are
applicable to the towers accessories listed in following sections
4. CLIMBING LADDER:
- Climbing ladder and climbing devices shall be provided.
- Provisions shall be made and all material pervaded for the installation of an
internal climbing ladder from the base to the tower top. The rung width shall
be at least 40.0 cm with the step diameter being a minimum of 1.6 cm; the
maximum adjacent rung spacing shall be 40.0 cm. The step spacing shall be
uniform throughout the ladder length.
5. WAVE GUIDE SUPPORT
- Waveguide Ladder, Provisions shall be made and all material pervaded for the
installation of an internal waveguide ladder from the base to tower top. These
ladders shall provide secure support coax runs for at least 10 runs of coax
along the tower length. The ladders have 0.9 to 1.2 meters rung spacing. - Waveguide Bridge (Cable Tray) shall provide support and protection of
waveguide to equipment shelter, Tower and shelter are 5 to 8 meters apart. - Waveguide support structures shall be grounded in accordance with the tower
grounding specification.
6. CONNECTIONS AND LOCKING DEVICES
- All members shall be connected with galvanized structural bolts unless
otherwise approved by PSD. - The contractor shall provide bolts, nuts and lock washers in a quantity 5% in
excess of the actual bolt count, for each size required for each Tower. - All towers will be provided with the correct size and length of anchor bolts
necessary to carry the anticipated Tower loads. If the Tower loads require
more than one bolt per leg, they shall be shop welded into a cluster to
eliminate the need for a template during field installation. - All threaded fasteners shall extend not less than 2 threads beyond nuts and
locking devices.
7. REST PLATFORMS
- Rest platforms shall be placed at intervals 15 meters.(45M/60M Towers Only)
- A rest platform will consist of a level platform of grating which allows room
for two persons. - Safety hand rails shall be provided around the rest platforms.
- Work platforms with safety hand rails shall be provided around Microwave
antennas.
8. TOWER LIGHTNG
- Obstruction lighting systems shall be supplied with the towers and installed as
required CAA. - An electronic device equipped with a photoelectric cell that change over lights
on and off automatically from dawn till dusk and provide alarms indicating
beacon or/and power failure. - Obstruction lighting system shall be capable of indicating when light is turned
on or off. - Contractor shall submit schematic, installation drawing and specifications of
the obstruction light system he is providing.
9. GROUNDING AND LIGHTNING PROTECTION
- Towers shall have a complete grounding system which conforms to the
minimum requirements of EIA RS-222-F, “Protective Grounding”. - The grounding system of tower shall achieve a resistance to earth less than 5
ohm. - The grounding system of tower shall be interconnected with shelter grounding
system to provide a common ground potential to the communications site.
This shall include lightning protection, electric service and antenna system
ground. - The grounding system may consist of, but is not limited to, the following
components:
- Tower ground ring.
- Ground radials.
- Grounding electrodes.
- Tower ground bus bar.
- External ground bus bar. - Tower ground ring shall be buried and encircles the tower structure and
provide a means of bonding ground rods together and bonding other
grounding electrode system components together. - The Tower ground bus bar shall be an integral part of the tower construction
or vertical waveguide ladder it should be large enough to accommodate all
coaxial cable connections and connection to the grounding electrode system.
The tower ground bus bar shall be physically and electrically connected to the
Tower, it shall be installed below the transmission line ground kits, near the
area of the tower at the point where the antenna transmission lines transition
from the tower to the shelter. - Near end ground bus bar shall be installed at the point where the antenna
transmission lines enters the shelter (or building), and shall be connected to
the external ground ring using the straightest possible downward run of 35
mm2 csa (#2 AWG) or larger bare solid or stranded tinned copper conductor,
it should be large enough to accommodate all coaxial connections and
connection to the grounding electrode System PSD. - Each leg of the towers shall be bonded to the tower ground ring using
grounding conductors of 35 mm2 csa (#2 AWG) minimum, bare tinned solid
or stranded copper conductor. - Tower grounding system shall be connection ready to be interconnected with
shelter (or building) ground. - Exothermically welding shall be used for connecting grounding system
elements, other methods of connection shall not be used. - Each tower must be equipped with a lightning rod fastened at the extreme top
of the tower, the lightning rod shall be made of galvanized steel, with
minimum dimensions of 1.6 cm diameter by 1.2 meter long, shall be attached
so as to extend a minimum of 45 cm above the highest point of the tower,
including all attachments.
10. Tower Base Excavations:
- All excavation works shall conform to relevant Jordanian codes.
- The contractor shall insure that each foundation excavation is accurately
located, sized and plumbed as specified on the drawings. - All topsoil shall be separately removed and stockpiled for rater use in the final
Back-filling process. No waste from excavations shall be spread on the
property without the approval of the PSD. Excavated material, unsuitable or
not required for Back-filling shall be removed from the site and disposed of
by the Contractor in local authorities Specified dump areas. - Site Safety Measures & Tools are the responsibility of the contractor.
Excavation shall not be left open .
11. Tower Base Foundations :
- All materials, cement, fine aggregate, coarse aggregate, water and admixtures
shall conform to relevant Jordanian codes. - Foundation designs shall be based upon the soil characteristics and parameters
listed in the site geotechnical report supplied by PSD. - Foundation shall be designed for maximum structure reaction resulting from
the specific loads. - Foundation drawings shall indicate structure reactions, material strengths,
dimensions, reinforcing steel and embedded anchorage material type, size and
location. - Foundation shall use ready-mix concrete, concrete shall conform to standards
and codes adopted in Jordan. - All concrete construction methods shall conform to the standards practiced
and adopted in Jordan or equivalent international standard. - The contractor shall submit a detailed report of material specifications used in
Concrete Mix Design. - o ensure uniform production of concrete, representative samples will be
taken at the request of and under the supervision of the PSD engineer and
contractor assigned engineer for the purpose of making cubes for strength
tests. All tests shall conform to standards and codes adopted in Jordan. - In case the concrete placed by the contractor is determined, by testing "to be
defective or not accepted" in any way, the contractor shall be responsible and
at his expense for one of the following courses of action which shall be
determined by PSD:
- Removal and replacement of all defective concrete.
- The cost of design and construction changes necessary to incorporate the
inferior concrete. - All reinforcement shall conform to relevant Jordanian codes. All
reinforcement cages, anchor bolts, anchor rods, etc. Shall be accurately
positioned and secured while concrete is being poured and vibrated. Exposed
portions of anchor bolts shall be coated with tape or heavy grease prior to
pouring concrete. The contractor shall provide All bar supports, ties, spacers
and other materials required to keep the reinforcing in its proper position. - Heating of rebar in order to bend it and welding of rebar will not be permitted.
- The portion of concrete surfaces exposed above grade shall be fair faced
concrete.
12. BACKFILL
- All backfill works shall conform to relevant Jordanian specifications.
- Material for backfill shall be furnished by the Contractor from the excavated
site material to the extent available. Additional backfill ‘similar to the site
material, shall be furnished by the Contractor where required. If excavated
material is not suitable as backfill, Contractor will replace it with acceptable
material. - Fill materials shall be placed in horizontal layers of 25cm lifts and each layer
compacted with vibrating compactors such as tampers ‘rammers, or vibro
plates to 95% modified proctor density. - The finished grade at backfilled and other disturbed areas shall conform to the
lines and grades of the site. Areas around buildings and towers shall be graded
so as to cause surface water to flow away from them.
13. TOWER ERECTION
- The contractor shall furnish all necessary personnel, supervision ‘tools,
equipment and transportation required to complete the installation and
erection of all items specified herein. - Any Tower elements which sustain damage shall be reported to PSD.
- Correction of damage shall not be done by contractor without the approval of
PSD. - The actual location of the tower and other structures will be determined by
PSD, Tower orientation shall be agreed upon later on between PSD and the
contractor. - The Structural members shall be accurately set to lines and evasions indicated
on the erection drawings, also the various members forming each tower bay
shall be aligned and adjusted before permanently fastening. - The contractor shall maintain a check of Tower plumpness during all phases
of the erection work. Plumpness shall be measured by means of a transit
placed so that the sight elevation angles are less than 45 degrees. At least two
sights shall be made for each check, oriented at right angles to each other and
taken within the shortest practical time interval. At all times the tower shall be
plumb within the tolerance specified in drawings. After completion of tower
construction, with all joints tight, and all appurtenances installed ‘the
contractor shall make a final check of tower plumpness in the manner
prescribed above - Field modifications including welding or burning of holes in members are not
acceptable. - Contractor shall provide a dedicated, full-time field supervisor. This
contractor-employee will be assigned and available through all phases of
construction. Responsibilities will include, but not be limited to: verification
of tower and anchor locations; finished grade and construction of foundations;
delivery and erection of tower; off-Load location and joint inspection of
construction.
14. CLIMBING TOOLS
Contractor is required to provide as an option a recommended list of climbing
tools e.g. full body harness, safety blocks, rescue and retrieval system, shock
absorbers
15. INSTRUCTIONS FOR CONTRACTOR
Contractor Shall provide complete erected functioning 60 meter towers
according to specifications and requirements listed in this document.
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