COMMUNICATION STRUCTURES SPECIFICATIONS · • TIA/EIA-222-Rev F vs. TIA-222-Rev G ... structure was out of service for an extended period of time (TIA-222-G) • Class 1 (I=0.87):

© 2010 Valmont Industries, Inc. All rights reserved.

COMMUNICATION

STRUCTURES SPECIFICATIONS

Steve Krohn, P.E.


Make Sure You Get What You Order…Today

and in the Future

• Explain the implications of good specifications

• Short term and long term financial impacts

• Are you getting everything you are asking for?

• Comparison of Specification Interpretations

• Examples of specifications based on our experience

• Question and Answer session


Structure Specifications

Are you meeting your future requirements?

Is your 4 carrier structure really a 4 carrier

structure?

Are you really saving money?

Is today’s choice affecting tomorrow’s

reinforcement budget?


Structure Specifications

“The Playbook”

Basic Requirements

Details your design expectations

Provides the loading requirements that you have

specified for current and future use

Provide the same specifications to all

manufacturers so you receive comparable bids

Ensures all manufacturers are designing based

on the same requirements


Important Specification Information

• Structure Height

• Design Code

• Mount Options

• Antenna/Microwave Mount Locations • Design purposes only?

• Antenna Sizes

• Dish Specifications

• Site Location • Longitude and Latitude

• Exposure Category

• Topography Category

• Structure Classification

• Cable/Waveguide Size and Quantity

• Additional Load Clarification


Design Code Options

• TIA/EIA-222-Rev F vs. TIA-222-Rev G

• Rev F

• Allowable Design

• Fastest Mile wind speed

• Rev G

• Limit State Design

• 3-sec gust wind speed

• Site Characteristics included when considering wind loading

• Includes Seismic and Ice Loading consideration

• 90 mph Rev G is approximately 75 mph Rev F


• Platforms

• 13’ Low Profile Platform without handrails

• 13’ Low Profile Platform with handrails

• Extensions Arms

• T-Arms

• Significant EPA differences

Mount Options


Antenna Size

• Effective Projected Area typically accounts for

more than 50% of the forces on the pole

• (48)- 6’ x 1’ x 4” antennas: EPA= 390.2 ft2

• (48)- 8’ x 1’ x 4” antennas: EPA= 550.5 ft2


Site Characteristics and Structure Classification

• Exposure Category • Variations in ground surface roughness that arise from topography and vegetation as

well as from constructed features. (TIA-222-G)

• Exposure B: Structures in Urban or Suburban areas.

• Exposure C (default): Structures located in open terrain scattered with obstructions

that are less than 30’ tall.

• Exposure D: Structure is in flat, unobstructed shoreline exposed to wind flowing over

open water.


• Topography Category • Location of structure to hills, ridges, and escarpments that constitute abrupt changes in

geography will result in wind speed-up effects. (TIA-222-G)

• Category 1 (default)- No abrupt changes in general topography.

• Category 2- Structures located at or near the crest of an escarpment.

• Category 3- Structures located in the upper half of a hill.

• Category 4- Structures located in the upper half of a ridge or mountain.


Escarpment Flat Hill Mountain



• Structure Classification • Importance factor based on classification of human hazard/property damage if

structure was out of service for an extended period of time (TIA-222-G)

• Class 1 (I=0.87): Structures that due to height, use or location represent a low hazard

to human life and damage to property in the event of a failure and/or used for

services that are optional. I.E. Ham Radio Tower

• Class 2 (I=1.0) (default): Structures that due to height, use or location represent a

substantial hazard to human life and damage to property in the event of a failure

and/or used for services that may be provided by other means. I.E. Typical Cell Tower

• Class 3 (I=1.15): Structures that due to height, use or location represent a high hazard

to human life and damage to property in the event of a failure and/or used for

primary communication. I.E. Emergency Response Tower


Dish Specifications

• Sway Requirements based on dish

frequency and dish size

• The higher the frequency the stricter

the twist and sway requirements


Steps to competitive and proper designs

Well written specifications

Contact Valmont Industries for all your

specification questions and concerns.

Provide any clarification to all manufacturers

Review designs

Ensure that specifications are adhered to

If base reactions are significantly different there

is a difference in specification interpretation


Steps to competitive and proper designs 14

The lowest price doesn’t always meet your

needs.

Did you get what you wanted?


Questions 15



• Exposure Category • Variations in ground surface roughness that arise from topography and vegetation as

well as from constructed features. (TIA-222-G)

• 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 a ll directions for a distance of at least 2,630 ft

(800m) or ten times the height of the structure, whichever is greater.

• Exposure C: Structures located in open terrain scattered with obstructions that are less

than 30’ tall (9.1m). This category includes flat, open country, grasslands and

shorelines in hurricane prone regions.

• Exposure D: Structure is in flat, unobstructed shoreline exposed to wind flowing over

open water (excluding 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 ten times

the height of the structure, whichever is greater. Smooth mud flats, salt flats and other

similar terrain shall be considered as Exposure D.

Documents

COMMUNICATION STRUCTURES SPECIFICATIONS · • TIA/EIA-222-Rev F vs. TIA-222-Rev G ... structure was out of service for an extended period of time (TIA-222-G) • Class 1 (I=0.87):