Preface
This is the eighth edition of CAN/CSA-S37, Antennas, towers, and antenna-supporting structures. It supersedes the previous editions published in 2013, 2001, 1994, 1986, 1981, 1976, and 1965.
The following is a list of some of the more important changes made in this edition:
a) Clause 4.6 was added for consideration in the structural analysis of known future antenna loading combinations.
b) Clause 5.3.4 was added with recommendations for load cases with discrete attachments installed on a structure for a period of 4 months or less.
c) The wind velocity pressure, qh, was redefined.
d) The inclusion of drag coefficients, Cd, for attachments of additional shapes.
e) The addition of an effective projected area formula to account for loads normal to the wind direction.
f) The elimination of the Cg of 2.5 in the calculation of the wind load of monopole structures. The dynamic response to wind for monopoles and shrouded tripoles will be taken into account by the new load combination WF (fatigue loading combination) in accordance with a normative Annex N.
g) Clause 7.3.8 was added to provide factored resistance formulas for link plates.
h) The factor resistance formulas were revised to include bending moments of anchor rods installed without high strength grout.
i) Clause 7.5.8 was added to include U-bolt material, installation, torqueing, and design recommendations.
j) Clause 11.2.2 was added for consideration of guy resultant angle variations in guy anchor shaft analysis and design.
k) Emphasis on additional engineering for construction loads on existing towers and guidance on temporary construction wind speed.
l) Alignment with recommendations from Canada Labour Code on load requirements for fall arrestors and vertical rigid rails.
m) Additional requirements for qualified climbers were provided.
n) Additional recommendations on corrosion protection of guy anchorages (Annex F) were provided.
o) Additional recommendations for geotechnical site investigation to include requirements for corrosive soils (Annex L) were provided.
p) Additional recommendations for tower condition assessment to emphasize importance of initial construction inspections and the recording of critical information (Annex D) were provided.
A commentary on this Standard is found in Annexes K and S.
CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of Bell, Nav Canada, Hydro-Québec, Rogers Communication Cda Inc., CBC Ontario, NorthWesTel Inc., Telus, and Videotron.
This Standard was prepared by the Technical Committee on Antenna Towers, under the jurisdiction of the Strategic Steering Committee for Construction and Civil Infrastructure, and has been formally approved by the Technical Committee. The new Annex T was developed with additional support from Alex Cannon, Dae Il Jeong, and Boris Weisman.
This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.
Scope
1.1 General
This Standard applies to structural antennas, towers, antenna-supporting structures, and roof- and wall- mounted structures, including their components, such as guys and foundations. It covers the structural design, fabrication, and erection of new structures and the modification of existing structures.
1.2 Exclusions
This Standard is not intended to apply to
a) attachment antennas and arrays or assemblies of such antennas; or
b) towers that support attachment antennas, extending less than 15 m above grade, including the height of any structure on which they are mounted.
1.3 Unusual designs and antennas
This Standard covers the requirements for most structural antennas, antenna towers, and antenna- supporting structures, but it is recognized that structures that are unusual with regard to their height or shape, or with regard to the shape and size of individual members, or that are located on sites having unusual topographical, geological, or climatic conditions might not be adequately covered. In such cases, appropriate engineering principles providing a level of reliability at least equivalent to that provided by this Standard should be applied.
1.4 Dynamic effects of wind
Other than the requirements of Annex N, this Standard does not contain mandatory requirements that take into account the dynamic effects of wind.
1.5 Other design approaches
A rational design based on theory, analysis, and engineering practice, acceptable to the owner and regulatory authority, may be used in lieu of the design procedures or materials described in this Standard. In such cases, the design should be prepared by an engineer qualified in the specific method and knowledgeable about the materials to be used, and should provide a level of safety and performance that is not less than that implicit in this Standard.
1.6 Local, provincial, and federal regulations
Responsibility for observing all applicable local, provincial, and federal regulations is not relieved by compliance with this Standard.
1.7 Terminology
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.
