TIA-222-G-2 - 2009.pdf

TIA-222-G-2 December 2009

Structural Standard for Antenna Supporting Structures and Antennas- Addendum 2

ANSI/TIA-222-G-2-2009

APPROVED: NOVEMBER 24, 2009

Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

NOTICE

TIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for their particular need. The existence of such Standards and Publications shall not in any respect preclude any member or non-member of TIA from manufacturing or selling products not conforming to such Standards and Publications.

Neither shall the existence of such Standards and Publications preclude their voluntary use by Non-TIA members, either domestically or internationally.

Standards and Publications are adopted by TIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, TIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication.

This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use.

(From Standards Proposal No. 3-3278-RV7-AD2, formulated under the cognizance of the TIA TR-14 Point-to-Point Communications Systems, TR-14.7 Subcommittee on Structural Standards for Steel Antenna Towers and Antenna Supporting Structures.)

Published by

�TELECOMMUNICATIONS INDUSTRY ASSOCIATION

Standards and Technology Department

2500 Wilson Boulevard Arlington, VA 22201 U.S.A.

PRICE: Please refer to current Catalog of

TIA TELECOMMUNICATIONS INDUSTRY ASSOCIATION STANDARDS

AND ENGINEERING PUBLICATIONS

or call IHS, USA and Canada

(1-877-413-5187) International (303-397-2896) or search online at http://www.tiaonline.org/standards/catalog/

All rights reserved Printed in U.S.A.

Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

NOTICE OF COPYRIGHT

This document is copyrighted by the TIA.

Reproduction of these documents either in hard copy or soft copy (including posting on the web) is prohibited without copyright permission. For copyright permission to reproduce portions of this document, please contact TIA Standards Department or go to the TIA website (www.tiaonline.org) for details on how to request permission. Details are located at:

http://www.tiaonline.org/standards/catalog/info.cfm#copyright

OR

Telecommunications Industry Association Standards & Technology Department

2500 Wilson Boulevard, Suite 300 Arlington, VA 22201 USA

+1(703)907-7700

Organizations may obtain permission to reproduce a limited number of copies by entering into a license agreement. For information, contact:

IHS

15 Inverness Way East

Englewood, CO 80112-5704 or call U.S.A. and Canada (1-800-525-7052)

International (303-790-0600)

Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

NOTICE OF DISCLAIMER AND LIMITATION OF LIABILITY

The document to which this Notice is affixed (the “Document”) has been prepared by one or more Engineering Committees or Formulating Groups of the Telecommunications Industry Association (“TIA”). TIA is not the author of the Document contents, but publishes and claims copyright to the Document pursuant to licenses and permission granted by the authors of the contents.

TIA Engineering Committees and Formulating Groups are expected to conduct their affairs in accordance with the TIA Engineering Manual (“Manual”), the current and predecessor versions of which are available at http://www.tiaonline.org/standards/procedures/manuals/TIA’s function is to administer the process, but not the content, of document preparation in accordance with the Manual and, when appropriate, the policies and procedures of the American National Standards Institute (“ANSI”). TIA does not evaluate, test, verify or investigate the information, accuracy, soundness, or credibility of the contents of the Document. In publishing the Document, TIA disclaims any undertaking to perform any duty owed to or for anyone.

If the Document is identified or marked as a project number (PN) document, or as a standards proposal (SP) document, persons or parties reading or in any way interested in the Document are cautioned that: (a) the Document is a proposal; (b) there is no assurance that the Document will be approved by any Committee of TIA or any other body in its present or any other form; (c) the Document may be amended, modified or changed in the standards development or any editing process.

The use or practice of contents of this Document may involve the use of intellectual property rights (“IPR”), including pending or issued patents, or copyrights, owned by one or more parties. TIA makes no search or investigation for IPR. When IPR consisting of patents and published pending patent applications are claimed and called to TIA’s attention, a statement from the holder thereof is requested, all in accordance with the Manual. TIA takes no position with reference to, and disclaims any obligation to investigate or inquire into, the scope or validity of any claims of IPR. TIA will neither be a party to discussions of any licensing terms or conditions, which are instead left to the parties involved, nor will TIA opine or judge whether proposed licensing terms or conditions are reasonable or non-discriminatory. TIA does not warrant or represent that procedures or practices suggested or provided in the Manual have been complied with as respects the Document or its contents.

If the Document contains one or more Normative References to a document published by another organization (“other SSO”) engaged in the formulation, development or publication of standards (whether designated as a standard, specification, recommendation or otherwise), whether such reference consists of mandatory, alternate or optional elements (as defined in the TIA Engineering Manual, 4th edition) then (i) TIA disclaims any duty or obligation to search or investigate the records of any other SSO for IPR or letters of assurance relating to any such Normative Reference; (ii) TIA’s policy of encouragement of voluntary disclosure (see Engineering Manual Section 6.5.1) of Essential Patent(s) and published pending patent applications shall apply; and (iii) Information as to claims of IPR in the records or publications of the other SSO shall not constitute identification to TIA of a claim of Essential Patent(s) or published pending patent applications.

TIA does not enforce or monitor compliance with the contents of the Document. TIA does not certify, inspect, test or otherwise investigate products, designs or services or any claims of compliance with the contents of the Document.

ALL WARRANTIES, EXPRESS OR IMPLIED, ARE DISCLAIMED, INCLUDING WITHOUT LIMITATION, ANY AND ALL WARRANTIES CONCERNING THE ACCURACY OF THE CONTENTS, ITS FITNESS OR

APPROPRIATENESS FOR A PARTICULAR PURPOSE OR USE, ITS MERCHANTABILITY AND ITS

NONINFRINGEMENT OF ANY THIRD PARTY’S INTELLECTUAL PROPERTY RIGHTS. TIA EXPRESSLY

DISCLAIMS ANY AND ALL RESPONSIBILITIES FOR THE ACCURACY OF THE CONTENTS AND

MAKES NO REPRESENTATIONS OR WARRANTIES REGARDING THE CONTENT’S COMPLIANCE

WITH ANY APPLICABLE STATUTE, RULE OR REGULATION, OR THE SAFETY OR HEALTH EFFECTS

OF THE CONTENTS OR ANY PRODUCT OR SERVICE REFERRED TO IN THE DOCUMENT OR

PRODUCED OR RENDERED TO COMPLY WITH THE CONTENTS.

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

TIA SHALL NOT BE LIABLE FOR ANY AND ALL DAMAGES, DIRECT OR INDIRECT, ARISING FROM

OR RELATING TO ANY USE OF THE CONTENTS CONTAINED HEREIN, INCLUDING WITHOUT

LIMITATION ANY AND ALL INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES

(INCLUDING DAMAGES FOR LOSS OF BUSINESS, LOSS OF PROFITS, LITIGATION, OR THE LIKE), WHETHER BASED UPON BREACH OF CONTRACT, BREACH OF WARRANTY, TORT (INCLUDING

NEGLIGENCE), PRODUCT LIABILITY OR OTHERWISE, EVEN IF ADVISED OF THE POSSIBILITY OF

SUCH DAMAGES. THE FOREGOING NEGATION OF DAMAGES IS A FUNDAMENTAL ELEMENT OF

THE USE OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA

WITHOUT SUCH LIMITATIONS.

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

ANSI/TIA-222-G

Addendum 2

Summary of Changes

1. Page 4 Table of Contents – Page numbering

2. Page 12 2.6.5.1 – Exposure C

3. Page 21 2.6.9.2 – Shielding factor, Ka

4. Page 22 2.6.9.2.1 – Ca for mounting pipes

5. Page 24 2.6.9.3 – Typo correction

6. Page 25 2.6.9.4 – Shielding limitations

7. Page 25 2.6.9.5 – Transmission line clusters

8. Page 27 2.7.2 – Definition of W

9. Page 29 2.7.7 – Definition of W

10. Page 30 2.7.7.1 – Definition of W

11. Page 39 Table 2-1 – Classification of structures

12. Page 59 3.4 – Analysis models

13. Page 60 3.4.1 – Application of forces to structural models

14. Page 60 3.6 – Typo correction

15. Page 61 Rearranged page format

16. Page 68 4.3 – Symbols & notations

17. Page 71 4.5.2.1 – Out-of-plane buckling of diagonals

18. Page 72 4.5.3 – Double angle members

19. Page 73 4.5.3 – Typo correction

20. Page 75 4.6.3 – Block shear rupture

21. Page 76 4.6.3.2 – Effective net area

22. Page 77 4.6.3.2 – Effective net area

23. Page 78 4.7.4.1 – Effective yield stress for single angles

24. Page 81 4.8.1.1 – Joint eccentricities

25. Page 85 4.9.6.3 – Slotted holes

26. Page 86 4.9.6.5 – Connecting elements

27. Page 87 4.9.8 – Guy assembly link plates

28. Page 97 Table 4-8 – Effective yield stress for polygonal shapes

29. Page 103 5.4.2 – Typo correction

30. Page 103 5.4.4 – Tolerances for HSS members

31. Page 108 7.4.5 – Guy hardware material

32. Page 108 7.4.6.1 – Guy hardware material

33. Page 110 8.2 – Insulator End Fitting Material

34. Page 111 8.3 – Proof loading of insulators

35. Page 112 9.4.1 – Typo correction

36. Page 112 9.5 – Typo correction

37. Page 116 12.3 – Safety cages on ladders

38. Page 120 13.3.5 – Slip joint tolerance

39. Page 120 14.2 – Maintenance and condition assessment intervals

40. Page 121 15.4 – Changed conditions for existing structures

41. Page 122 15.5.2 – Typo correction

42. Page 123 15.7.1 – Modification of existing structures

43. Page 124 Annex A.2.3.2 – Survival condition

44. Page 196 Annex B – County listing notes

45. Page 213 Annex J – Condition assessment of pole structures

46. Page 225 Annex L – Revised wind speed conversion to match IBC 2006

47. Page 235 Appendix 1 – Remove notes 2 and 3 on Figure A1-2c

48. Page 236 Appendix 1 – Remove note 3 on Figure A1-2d

49. Page 237 Appendix 1 – Remove note 3 on Figure A1-2e

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

14.0 MAINTENANCE AND CONDITION ASSESSMENT 120

14.1 Scope 120

14.2 Maximum Intervals 120

15.0 EXISTING STRUCTURES 120

15.1 Scope 120

15.2 Definitions 120

15.3 Classification 121

15.4 Changed Conditions Requiring a Structural Analysis 121

15.5 Structural Analysis 122

15.6 Exemptions 122

15.7 Modification of Existing Structures 123

16.0 INSTALLATION 123

ANNEX A: PROCUREMENT AND USER GUIDELINES (NORMATIVE) 124

ANNEX B: U.S. COUNTY LISTINGS OF DESIGN CRITERIA (NORMATIVE) 128

ANNEX C: DESIGN WIND FORCE ON TYPICAL ANTENNAS (NORMATIVE) 197

ANNEX D: TWIST AND SWAY LIMITATIONS FOR MICROWAVE ANTENNAS

(NORMATIVE) 204

ANNEX E: GUY RUPTURE (NORMATIVE) 205

ANNEX F: PRESUMPTIVE SOIL PARAMETERS (NORMATIVE) 208

ANNEX G: GEOTECHNICAL INVESTIGATIONS (NORMATIVE) 209

ANNEX H: ADDITIONAL CORROSION CONTROL (NORMATIVE) 210

ANNEX I: CLIMBER ATTACHMENT ANCHORAGES (NORMATIVE) 211

ANNEX J: MAINTAINANCE AND CONDITION ASSESSMENT (NORMATIVE) 213

ANNEX K: MEASURING GUY TENSIONS (NORMATIVE) 220

ANNEX L: WIND SPEED CONVERSIONS (NORMATIVE) 225

4Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

5. A topographic category and topographic factor, Kzt, shall be determined in accordance with 2.6.6.

6. A gust effect factor, Gh, shall be determined in accordance with 2.6.7.

7. The design ice thickness shall be escalated with height in accordance with 2.6.8.

8. The design wind force shall be determined in accordance with 2.6.9.

2.6.4 Basic Wind Speed and Design Ice Thickness

The basic wind speed without ice, the basic wind speed with ice and the design ice thickness shall be as given in Annex B except as provided in 2.6.4.1. Wind shall be considered to come from any horizontal direction. Ice shall be considered to be glaze ice.

Ice may be ignored for structures located in regions where the design ice thickness is less than or equal to 0.25 inches (6 mm).

2.6.4.1 Estimation of Basic Wind Speeds and Design Ice Thickness from Regional Climatic Data

For regions not included in Annex B, for the special wind or ice regions indicated in Annex B, and for sites where records indicate that in-cloud icing produces significant loads, extreme-value statistical-analysis procedures shall be used to establish design values consistent with this Standard from available climatic data accounting for the length of record, sampling error, averaging time, anemometer height, data quality, and terrain exposure.

2.6.5 Exposure Categories

2.6.5.1 General

An exposure category that adequately reflects the characteristics of ground surface irregularities at the site shall be determined. Account shall be taken of variations in ground surface roughness that arise from natural topography and vegetation as well as from constructed features. The exposure category for a structure shall be assessed as being one of the following:

1. Exposure B: Urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger. Use of this exposure shall be limited to those areas for which terrain representative of Exposure B surrounds the structure in all directions for a distance of at least 2,600 ft [800 m] or twenty times the height of the structure, whichever is greater.

2. Exposure C: Open terrain with scattered obstructions having heights generally less than 30 ft [9.1 m]. This category includes flat, open country, grasslands and shorelines in hurricane prone regions. Sites located in Exposure B terrain that are located further than two miles but less than twenty times the height of the structure from an Exposure D terrain.

3. Exposure D: Flat, unobstructed shorelines exposed to wind flowing over open water (excluding shorelines in hurricane prone regions) for a distance of at least 1 mile [1.61 km]. Shorelines in Exposure D include inland waterways, lakes and non-hurricane coastal areas. Exposure D extends inland a distance of 660 ft [200 m] or twenty times the height of the structure, whichever is greater. Smooth mud flats, salt flats and other similar terrain shall be considered as Exposure D.

12Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS where:

Ka = 1.0 for round appurtenances, regardless of location, when transitional or supercritical force coefficients are considered

= (1- �) for appurtenances when subcritical force coefficients are considered, located entirely inside the cross section of a latticed structure or outside the cross section entirely within a face zone as defined in Figure 2-3, where � is the minimum solidity ratio of the structure considering each face for the section containing the appurtenance. Ka need not exceed 0.6

= 0.8 for antennas and antenna mounting configurations that do not project above the top of the structure (when subcritical force coefficients are considered only) such as side arms, T-arms, stand-offs, etc. when 3 or more mounts are located at the same relative elevation (shielding from the mounting configuration and shielding of mounting members from antennas is excluded except as provided in 2.6.9.2.1, refer to 2.6.9.4)

= 1.0 for other appurtenances unless otherwise specified in this section

(Notes: 1. Ka = 1.0 may be conservatively used for any appurtenance

2. The value of Ka is constant for all wind directions

3. The Ka values specified above shall not be applied in addition to the applicable Ka values specifed in 2.6.9.2.2 through 2.6.9.2.5)

� = relative angle between the azimuth associated with the normal face of the appurtenance and the wind direction (refer to Figure 2-4)

(EPA)N = effective projected area associated with the windward face normal to the azimuth of the appurtenance

(EPA)T = effective projected area associated with the windward side face of the appurtenance

The larger value of (EPA)N or (EPA)T may be conservatively used for (EPA)A for all wind directions.

In the absence of more accurate data, an appurtenance shall be considered as consisting of flat and round components in accordance with the following:

(EPA)N = �(Ca AA)N

(EPA)T = �(Ca AA)T

Ca = force coefficient from Table 2-8

AA = projected area of a component of the appurtenance. The additional projected area of ice shall be considered as a round component for loading combinations that include ice

Equivalent flat plate areas based on Revision C of this Standard shall be multiplied by a force coefficient, Ca, equal to 2.0 except when the appurtenance is made up of round members only, a force coefficient of 1.8 may be applied.

The total (EPA)A for a wireless carrier shall be determined in accordance with Annex C when specific antenna and mounting information is not available.

21Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

2.6.9.2.1 Antenna Mounting Pipes

The effective projected area of a mounting pipe above and below the shielded portion of the mounting pipe shall be included in the term �(Ca AA)N with Ca equal to 1.0. The effective projected area of the entire mounting pipe shall be included in the term �(Ca AA)T with Ca determined from Table 2-8.

2.6.9.2.2 Effective Projected Area for Mounting Frames (Figure 2-5) The effective projected area associated with the windward face normal to the azimuth of a mounting frame, (EPA)N, shall be determined from the equation:

(EPA)N = (EPA)MN + (EPA)FN

(EPA)MN = Effective projected area of the frame = Cas (Af + Rrf Ar)

Cas = 1.58 + 1.05 (0.6 - �)1.8 for � � 0.6

Cas = 1.58 + 2.63 (� - 0.6)2.0 for � > 0.6

Af = projected area of flat components of the mounting frame

Rrf = 0.6 + 0.4 �2

� = solidity ratio of mounting frame without antennas and mounting pipes = (Af + Ar)/Ag

Ar = projected area of round components of the mounting frame

Ag = gross area of the frame as if it were solid defined by the largest outside dimensions of the elements included in Af and Ar

Note: For square or triangular truss mounting frames (refer to Figure 2-5), Cas shall be equal to Cf in accordance with 2.6.9.1.1.

(EPA)FN = the effective projected area in a plane parallel to the face of the mounting frame of all members supporting the mounting frame = 0.5 [ 2.0(�Afs) + 1.2(�Ars)]

Afs = projected area of flat components supporting the mounting frame without regard to shielding or overlapping members

Ars = projected area of round components supporting the mounting frame without regard to shielding or overlapping members

The effective projected area associated with the windward side of a mounting frame, (EPA)T, shall be determined from the equation:

(EPA)T = (EPA)FT + 0.5� (EPA)FTi + 0.5 � (EPA)MT

22Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS supporting structure. A drag factor of 2.0 for flat members and a drag factor of 1.2 for round members shall be applied to the projected areas of all members. The total effective projected area shall be multiplied by factor equal to 0.75 for square platform and 0.67 for triangular platforms. The resulting effective projected area shall be used for all wind directions. No shielding shall be considered for the supporting structure. Antennas and mounting pipes supported on the platform shall be considered as generic appurtenances using a value of Ka equal to 0.8.

2.6.9.2.5 Effective Projected Area for Symmetrical Circular Ring Platforms The effective projected area, (EPA)A, of symmetrical circular ring platforms (refer to Fig 2-9) that are continuous around the perimeter of a structure shall be determined by considering the supporting members of the platform and the ring members as individual members. The projected area of each ring member shall be equal to the product of the diameter of the ring and the projected vertical dimension of the ring member exposed to the wind. The projected area of all supporting members for the entire platform shall be determined by projecting all supporting members onto a vertical plane without regard to shielding or overlapping members of the platform or the supporting structure. A drag factor of 2.0 for flat members and a drag factor of

1.2 for round members shall be applied to the projected areas of the supporting members and the ring members. A 0.50 factor shall be applied to total effective projected area of the supporting members and a 1.75 factor shall be applied to the total effective projected area of the ring members. The resulting total effective projected area shall be used for all wind directions.

No shielding shall be considered for the supporting structure. Antennas and mounting pipes supported on the platform shall be considered as generic appurtenances using a value of Ka equal to 0.8.

Notes for all mounting frame/platform types:

1. Ka shall equal 1.0 for antennas and antenna mounting pipes under transitional or supercritical flow conditions.

2. Grating and other horizontal working surfaces need not be included in the effective projected area.

2.6.9.3 Design Wind Force on Guys

The design wind force on guys, FG, shall be determined in accordance with the following equation:

FG = Cd d LG Gh qz sin2 �g

FG = force applied normal to the chord of the guy in the plane containing the guy chord and the wind, refer to Figure 2-10

Cd = 1.2, drag factor for guy d = guy diameter including ice for loading combinations that include ice

LG = length of guy

Gh = gust effect factor from 2.6.7.2 qz = velocity pressure at mid-height of guy from 2.6.9.6 � g = true angle of wind incidence to the guy chord

24Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

Note: A higher drag factor, Cd, or an increased effective guy diameter may be required when attachments such as spoilers, insulators, markers, etc. are attached to a guy.

The design wind force and ice thickness may be assumed to be uniform based on the velocity pressure and ice thickness at the mid-height of each guy or guy segment. The length of each guy or guy segment may be assumed to equal the chord length. The design wind force shall be considered as a distributed force normal to the guy chord.

For ground-supported structures, mid-height shall be referenced to the ground elevation at the base of the structure. For structures supported on buildings or other supporting structures, the mid-height of a guy shall be measured from the mid-height elevation of the guy to the ground level of the building or other supporting structure. The height z for a guy segment shall not be less than zero.

2.6.9.4 Shielding

Shielding, except as noted herein, may be considered for intersecting or parallel elements. The unshielded element shall be considered as flat unless both elements are round. Full shielding may be considered when the clear distance between the elements in the direction under consideration for determining effective projected areas (EPA) is less than or equal to 2.0 times the smallest projected dimension of the element in the direction under consideration. No shielding shall be considered for clear distance ratios greater than 4.0. Linear interpolation shall be allowed for ratios between 2.0 and 4.0. Refer to Figure 2-11.

Except as provided in 2.6.9.2.1, shielding from an appurtenance shall not be considered when a value of Ka less than 1.0 per 2.6.9.2 is used to determine the design wind force on the appurtenance.

Note: Shielding considerations will vary with wind direction.

2.6.9.5 Round or Elliptical Transmission Lines Mounted in Clusters or Blocks The projected area of each line in a cluster or block, independent of their spacing or location within the group, (i.e. no shielding of lines and no reduction of ice thickness) shall be included in the calculation of wind loads using a force coefficient, Ca, equal to 1.2 (based on round/elliptical lines), except that the group of lines need not be considered larger than an equivalent appurtenance with a width equal to the maximum out-to-out dimension of the group for both the normal and transverse sides with a force coefficient, Ca, equal to 1.5 for square or rectangular clusters and 1.2 for round clusters. Refer to Figure 2-12. For loading conditions that include ice, a force coefficient, Ca, equal to 1.5 shall apply for both round, square and rectangular clusters.

Note: The width of the equivalent appurtenance may be used for determining shielding in accordance with 2.6.9.4.

For purpose of calculating the weight of ice, the radial thickness of ice shall be considered on each individual line except that the total cross section of ice need not exceed the area of a cluster as indicated in Figure 2-12.

2.6.9.6 Velocity Pressure

The velocity pressure, qz, evaluated at height z shall be calculated by the following equation:

qz = 0.00256 Kz Kzt Kd V2 I (lb/ft2 )

= 0.613 Kz Kzt Kd V2 I [N/m2]

25Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

IS = moment of inertia of a section of a structure;

i = number designating the level of the structure;

Iavg = average moment of inertia of structure;

Ibot = moment of inertia at base of structure;

Itop = moment of inertia at top of structure;

Kg = equivalent stiffness of guys;

Km = simplified natural frequency conversion factor for guyed masts;

KS = coefficient used to determine fundamental frequencies of a structure;

ke = seismic force distribution exponent;

L = height of pole structure;

Lgi = average chord length of guys at elevation i;

LS = length of a section of a structure;

MS = total mass of a section of a structure;

m = subscript denoting quantities in the mth mode;

N = standard penetration resistance of a soil;

Ni = number of guys at guy elevation i;

n = number designating the uppermost level of the structure or number of guy levels;

PI = plastic index of a soil;

R = response modification coefficient;

S1 = maximum considered earthquake spectral response acceleration at 1 second;

SA = design spectral response acceleration;

Sam= design spectral response acceleration at period Tm;

Saz= acceleration coefficient at height z;

SD1 = design spectral response acceleration at a period of 1.0 second;

SDS = design spectral response acceleration at short periods;

Ss = spectral response acceleration at short period;

SU = undrained shear strength of a soil;

Tm = period for mode m;

TO = period used to define the design spectral response;

TS = period used to define the design spectral response;

Vs = total seismic shear;

Vsm = portion of the base shear contributed by the mth mode;

W = weight of structure above ground including appurtenances and upper half of guys;

WI = weight used to determine fundamental frequencies of a structure;

WL = weight of structure excluding appurtenances;

Wm= effective modal gravity load;

Wt = total weight of structure including appurtenances and guys;

Wu = weight of discrete appurtenances in the top third of structure;

W2 = weight of structure and appurtenances within top 5% of structure height;

wa = average face width of structure;

wi = portion of total gravity load assigned to level i;

wo = face width at base of structure;

wz = portion of total gravity load assigned to level under consideration;

z = number designating the level under consideration.

2.7.3 General

Antennas and antenna supporting structures require special considerations of their response characteristics in regions of high seismicity. The provisions of this Standard provide design

27Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

2.7.5 Maximum Considered Earthquake Spectral Response Accelerations The maximum considered earthquake spectral response accelerations at short periods (Ss) and at 1 second (S1) shall be as given in Annex B and Appendix 1 except as provided by 2.7.5.1.

2.7.5.1 Site-Specific Procedures for Determining Ground Motion Accelerations For structures located in regions not included in Annex B, the maximum accelerations Ss and S1 shall be based on regional seismicity and geology and shall be expressed as a ratio to the acceleration due to gravity. The maximum considered earthquake ground motion shall be taken as the motion represented by assuming 5% of critical damping having a 2% probability of exceedance within a 50 year period.

A site-specific geotechnical investigation and a dynamic site response analysis shall be used to determine Ss and S1 for structures in all Site Class F locations (see Tables 2-12 and 2-13).

2.7.6 Design Spectral Response Accelerations

The design earthquake spectral response acceleration at short periods, SDS, and at 1 second, SD1, shall be determined from the following equations:

SDS = 2/3 Fa Ss

SD1 = 2/3 Fv S1

Fa = acceleration-based site coefficient based on site class and spectral response acceleration at short periods from Table 2-12.

Fv = velocity-based site coefficient based on site class and spectral response acceleration at 1 second from Table 2-13

Note: when Ss and S1 are based on site-specific dynamic response analysis procedures, Fa and Fv shall be equal to 1.0.

2.7.7 Equivalent Lateral Force Procedure (Method 1)

1. Determine the total weight (W) of the structure above ground including appurtenances. For guyed masts, W shall also include the weight of the upper half of the guy assemblies attached to the structure.

2. Calculate the total seismic shear (Vs) in accordance with 2.7.7.1.

3. Distribute the total seismic shear in accordance with 2.7.7.2.

4. Analyze the structure statically using the seismic forces as external loads.

2.7.7.1 Total Seismic Shear

The total seismic shear, Vs, in a given direction shall be determined in accordance with the following equation:

29Provided by IHS under license with TIA

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

R

IWS

V

DS

s

Alternatively, for ground-supported structures, the total seismic shear, Vs, need not be greater than:

When the alternate equation for Vs is used, Vs shall not be less than 0.044 SDS W I and for sites where S1 equals or exceeds 0.75, Vs using the alternate equation shall also not be less than:

SDS = design spectral response acceleration at short periods from 2.7.6

SD1 = design spectral response acceleration at a period of 1.0 second from 2.7.6

S1 = maximum considered earthquake spectral response acceleration at 1 second from

2.7.5 f1 = fundamental frequency of the structure in accordance with 2.7.11

W = total weight of the structure above ground including appurtenances, for guyed masts, W also includes one-half the weight of guy assemblies

I = importance factor from Table 2-3

R = response modification coefficient equal to 3.0 for latticed self-supporting structures,

2.5 for latticed guyed masts and 1.5 for tubular pole structures

2.7.7.2 Vertical Distribution of Seismic Forces

The lateral seismic force, Fsz, induced at any level, z, shall be determined from the following equation:

sV n

1i ek ihiw ek zhzw szF

R IWSfV D11 s

R

IW0.5SV 1

s

30Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

Table 2-1 Classification of Structures

Description of Structure Class

Structures that due to height, use or location represent a low hazard to human life and damage to property in the event of failure and/or used for services that are optional and/or where a delay in returning the services would be acceptable.

I

Structures that due to height, use or location represent a significant hazard to human life and/or damage to property in the event of failure and/or used for services that may be provided by other means.

II

Structures that due to height, use or location represent a substantial hazard to human life and/or damage to property in the event of failure and/or used primarily for essential communications.

III

Table 2-2 Wind Direction Probability Factor

Structure Type Wind Direction Probability Factor, Kd

Latticed structures with triangular, square or rectangular cross sections including appurtenances

0.85

Tubular pole structures, latticed structures with other than triangular, square or rectangular cross sections, strength design of appurtenances

0.95

Table 2-3 Importance Factors

Structure

Class Wind Load Without Ice

Wind Load With Ice

Ice Thickness

Earthquake

I 0.87 N/A N/A N/A

II 1.00 1.00 1.00 1.00

III 1.15 1.00 1.25 1.50

Note: Ice and earthquake loads do not apply to Class I structures

39Provided by IHS under license with TIA

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

3.0 ANALYSIS

3.1 Scope

This section defines: (i) the minimum acceptable analysis models and techniques, and (ii) the requirements to account for the dynamic effects of wind gusts.

3.2 Definitions

For the purposes of this Standard, the following definitions apply.

Guyed mast: a latticed or pole structure with supporting guys.

Mast span: the distance between the base and the first guy level, the distance between two successive guy levels, or the distance above the top guy level to the top of the structure (cantilever span).

Mean wind conversion factor, m: a factor used to determine the mean hourly wind pressure.

3.3 Symbols and Notation

FA = horizontal design wind force for appurtenances;

FST = horizontal design wind force on the structure;

fwi = width of segment of structure;

h = height of a guyed mast ;

hi = height of segment of structure;

m = mean wind conversion factor;

P- = effects of displacement on member forces;

qz = velocity pressure.

3.4 Analysis Models

The minimum acceptable models of analysis are as follows:

(a) Self-Supporting Latticed Towers

1. An elastic three-dimensional truss model made up of straight members pin connected at joints producing only axial forces in the members.

2. An elastic three-dimensional frame-truss model where continuous members (legs, K-type bracing horizontals without plan bracing) are modeled as 3-D beam elements producing both moments and axial forces in the members while the remaining members which are subjected primarily to axial loads may be modeled as 3-D truss elements producing only axial forces in the members.

(b) Self-Supporting Pole Structures

An elastic three-dimensional beam-column model producing moments, shears and axial forces in the pole structure. Unless the analysis model considers second order effects within each element, the minimum number of beam elements shall be equal to five per pole section and the maximum beam element length shall not exceed 6 ft [1.8 m].

Note: Due to modeling complexity (e.g. meshing, element interconnection, etc.) of plate or shell models, the stresses obtained from such models shall not be less than the stresses obtained from the beam-column model noted above.

59Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

(c) Guyed Masts

1. An elastic three-dimensional beam-column where the mast is modeled as equivalent three-dimensional beam-column members supported by cables represented either as non-linear elastic supports or cable elements. This analysis produces moments, shear and axial forces in the mast, which results in individual member forces. For finite element beam-column models, unless the analysis model considers second-order effects within each element, a minimum of five elements shall be used in any span or cantilever.

2. An elastic three-dimensional truss model where individual members of the mast are modeled as straight members connected at joints producing only axial forces in the members. The cables are represented as cable elements.

3. An elastic three-dimensional frame-truss model where continuous members (legs) of the mast are modeled as 3-D beam elements producing both moments and axial forces in the members while other members may be modeled as 3-D truss members. The cables are represented as cable elements.

3.4.1 Application of Wind Forces to Structural Models

The horizontal design wind force on the structure, FST, shall be equally distributed to each leg joint of the cross-section at the panel points for three-dimensional truss or frame-truss models.

For three-dimensional beam-column models, wind forces shall be applied as either uniform loads or as concentrated loads distributed to the nodes on the beam-column.

The horizontal design wind force, FA, for appurtenances shall be distributed to the appropriate nodes in the model according to the location of the appurtenance (i.e. lateral load and torsion considered). For three-dimensional beam-columns, this will require applying torsional moments at the appropriate nodes.

Local bending shall be considered for structural components supporting appurtenances that are supported in the middle half of the component. For main bracing members, under this condition, local bending shall be considered for the condition of wind normal to the plane of the bracing members with no axial member load considered.

Note: Weight and earthquake forces shall be distributed and considered in a similar manner.

3.5 Displacement Effects

The analysis of all structures, except as provided herein, shall take into account the effects of displacements on member forces (P- effects). For guyed structures the effects of displacements of the guy points as well as the effects of displacements between guy points shall be considered. For finite element beam-column models, unless the analysis model considers second order effects within each element, the minimum number of beam elements between guy levels shall be equal to five. P- effects need not be considered for self-supporting latticed towers with heights less than 450 ft [137 m] provided that the height to face width ratios, hi/fwi, are less than 10 as shown in Figure 3-1.

3.6 Wind Loading Patterns

To account for the dynamic effects of wind gusts, the following wind loading patterns shall be considered for the strength limit state condition (refer to Figure 3-2 and 3-3):

3.6.1 Latticed Self-Supporting Towers

When the apex defined by the projection of the inclined legs of a latticed self-supporting tower lies within the height of the tower (refer to Figure 3-2), the following wind loading patterns shall

60Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS be investigated for load combination 1 as specified in 2.3.2 by varying the velocity pressure as follows:

1. Full velocity pressure over the entire height of the structure.

2. Full velocity pressure below the apex point and mean velocity pressure above the apex point.

3. Full velocity pressure above the apex point and mean velocity pressure below the apex point.

The mean velocity pressure shall be determined by multiplying the velocity pressure, (qz per 2.6.9.6) by the mean wind conversion factor, m, from Table 3-1.

The above loading patterns shall apply for each apex point in towers with multiple legs slopes that differ by more than 1 degree in adjacent sections. All combinations of wind loading patterns shall be considered when determining maximum load effects.

3.6.2 Guyed Masts

For guyed masts with three or more spans and with at least one mast span greater than 80 feet [24 m] within the top one-third of the height of the structure, the following wind loading patterns (refer to Figure 3-3) shall be investigated for load combination 1 as specified in 2.3.2 by varying the velocity pressure as follows:

1. Full velocity pressure over the entire height of the structure. For masts greater than 450 feet [137 m] in height, full wind pressure over the entire structure need not be considered when pattern loading is investigated.

2. Mean velocity pressure on the top mast span and full velocity pressure on the remaining spans.

3. Mean velocity pressure on the second mast span from the top and full velocity pressure on the remaining spans.

4. Mean velocity pressure on the third mast span from the top and full velocity pressure on the remaining spans

The mean velocity pressure shall be determined by multiplying the velocity pressure, (qz per 2.6.9.6) by the mean wind conversion factor, m, from Table 3-1. Full wind pressure shall be applied to guys for all pattern loadings.

Notes:

1. For masts with cantilevers (e.g. broadcast antenna structures, spines, or the mast itself), the cantilevers shall be considered as the top span.

2. For masts where the total length of the top three mast spans is less than one-third the height of the structure, the above wind loadings patterns shall be continued for each subsequent span until the total length of the considered spans is greater than one-third the height of the structure (refer to figure 3-3).

3. When the distance between two guy elevations is less than 3 times the larger face width between the guy elevations, the wind pressure patterns shall extend to the mid-point of the two guy elevations. The short span shall not be considered as an independent span for purposes of this section.

61Provided by IHS under license with TIA

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

K = effective length factor;

KL/r = effective slenderness ratio;

o r KL = effective slenderness ratio of built-up member acting as a unit;

m r KL = modified effective slenderness ratio of built up member;

L = laterally unbraced length of member;

LB = lateral unbraced length;

LT = torsional unbraced length;

L/r = slenderness ratio of member;

Lc = clear distance for design bearing strength;

Mn = nominal flexural strength;

Mnx = nominal flexural strength about the x-axis;

Mny = nominal flexural strength about the y-axis;

Mnw = nominal flexural strength about the major principal axis;

Mnz = nominal flexural strength about the minor principal axis;

Mu = flexural moment due to factored loads;

Muw = flexural moment about the major principal axis due to factored loads;

Muz = flexural moment about the minor principal axis due to factored loads;

Nt = flexural to torsional unbraced length ratio;

n = number of threads per inch;

p = pitch of threads;

Pe = elastic Euler buckling load;

Pl = nominal strength of a link plate;

Pn = nominal axial strength;

Pr = resistance required at a panel point within a face of a latticed structure;

Ps = minimum bracing resistance normal to the supported member;

Pu = axial compressive force due to factored loads;

r = governing radius of gyration about the axis of buckling;

ri = minimum radius of gyration of an individual component of a built-up member;

rib = radius of gyration of individual component about its centroidal axis parallel to the axis of buckling under consideration for the built-up member;

rx = governing radius of gyration about the x axis of buckling;

ry = governing radius of gyration about the y axis of buckling;

rz = governing radius of gyration about the z axis of buckling;

Rn = nominal bearing strength at bolt or attachment holes;

Rnp = nominal strength of connecting element;

Rnt = nominal tensile strength of bolt or anchor rod;

Rnv = nominal shear strength of bolt or anchor rod;

S = minimum elastic section modulus;

Sw = elastic section modulus to the leg tip about the major principal axis;

Sz = elastic section modulus to the leg tip about the minor principal axis;

s = longitudinal center to center spacing (pitch) of any two consecutive holes;

Tn = nominal torsional strength;

Tu = torsional moments due to factored loads;

Tub = bolt tensile force due to factored loads;

t = thickness of the member or of the critical connected part;

U = reduction factor for effective net area calculation;

Ubs = reduction coefficient for block shear rupture;

Vn = nominal shear strength;

Vub = bolt shear force due to factored loads;

Vu = transverse shear force due to factored loads;

Wn = net width of the part;

68Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS

A single bolt shall not be considered as providing partial restraint against rotation. It is permissible to consider a multiple bolt or welded connection to provide partial restraint if the connection is to a member capable of resisting rotation of the joint.

A multiple bolt or welded connection made only to a gusset plate without also being connected directly to the member providing restraint (i.e. leg member) shall not be considered to provide partial restraint in the out-of-plane direction.

4.5.2.1 Cross Bracing

The crossover point when connected shall be considered to provide support resisting out-of-plane buckling under any one of the following conditions:

(a) One of the diagonal members is continuous and one of the diagonal members is subjected to tension.

(b) Triangulated horizontal plan bracing (Fig. 4-2) is provided at the intersection point with sufficient resistance as defined in 4.4.1.

(c) A continuous horizontal member meeting the following criteria is connected at the crossover point:

i.The continuous horizontal has sufficient strength to provide resistance to the leg as defined in 4.4.1.

ii.The strength of the continuous horizontal is determined ignoring the out-of-plane buckling resistance of the diagonals.

Otherwise, the crossover point shall not be considered as providing support resisting out-of-plane buckling. (Refer to Table 4-6).

When there are no diagonal members continuous through the crossover point, either of the following conditions shall be satisfied:

(d) Triangulated horizontal plan bracing with sufficient resistance as defined in 4.4.1 is provided at the crossover point.

(e) A continuous horizontal with sufficient strength as defined in (c) above is provided through the crossover point.

4.5.2.2 K-Type or Portal Bracing

Triangulated plan bracing shall be provided at the bracing apex point with sufficient resistance as defined in 4.4.1 when the horizontal member is not a continuous member.

When triangulated plan bracing is not provided with a continuous horizontal, the out-of-plane unbraced length of the horizontal shall be considered to be 0.75 times the total length of the horizontal. The horizontal member shall have sufficient strength to provide strength to the legs as defined in 4.4.1 determined using the full length of the horizontal. (Refer to Table 4-7).

4.5.2.3 Cranked K Type or Portal Bracing

Triangulated internal hip bracing, with sufficient resistance as defined in 4.4.1, shall be provided at the main diagonal bend. (Refer to Figure 4-1).

4.5.3 Built-Up Members

Individual components of built-up members composed of two or more shapes shall be connected to one another at intervals, ai, such that the maximum slenderness ratio (ai/ri) of each

71Provided by IHS under license with TIA Licensee=FAA NAS/6110654001, User=Smith, Robert

Not for Resale, 10/01/2014 15:02:27 MDTNo reproduction or networking permitted without license from IHS of the component shapes between the connectors does not exceed 100% of the governing effective slenderness ratio of the built-up member.

A minimum of two bolts shall be used at each intermediate connector point when the connected width (i.e. connected leg width of a double angle) of a compression member exceeds 4 in. [102 mm].

For buckling modes that involve relative deformations that produce shear forces in the connectors (e.g. buckling about the axis parallel to the back-to-back legs for double angles), the effective slenderness ratio shall be modified by the following equations:

(a) When either end or intermediate bolted connectors are snug-tight bearing connections and a minimum of 2 intermediate connectors are used over the length considered for out-of-plane buckling such that ai/ri is not greater than 0.75(KL/r)o:

ibi i om r

KL

r a r

KL

r

KL

(b) When both end and intermediate connectors are welded or bolted using high-strength bolts tensioned to 70% of the published ultimate tensile bolt strength and the spacing of intermediate connectors result in ai/ri not greater than 0.75(KL/r)o:

� � ibib i i om r

KL

r a r

KL

r

82.0

(c) For all other conditions:

ibm r r

KL

o r

= effective…