Krohn_valmont_TIA.pdf

8/11/2019 Krohn_valmont_TIA.pdf

1/16

2010 Valmont Industries, Inc. All rights reserved.

COMMUNICATIONSTRUCTURES SPECIFICATIONS

Steve Krohn, P.E.


2/16


Make Sure You Get What You OrderTodayand in the Future

Explain the implications of goodspecifications 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


3/16


Structure Specifications

Are you meeting your future requirements?Is your 4 carrier structure really a 4 carrierstructure?

Are you really saving money?Is todays choice affecting tomorrowsreinforcement budget?


4/16


Structure SpecificationsThe Playbook

Basic RequirementsDetails your design expectationsProvides the loading requirements that you havespecified for current and future useProvide the same specifications to allmanufacturers so you receive comparable bids

Ensures all manufacturers are designing basedon the same requirements


5/16


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


6/16


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 windloading Includes Seismic and Ice Loading consideration

90 mph Rev G is approximately 75 mph Rev F


7/16 2010 Valmont Industries, Inc. All rights reserved.

Platforms 13 Low Profile Platform without handrails 13 Low Profile Platform with handrails

Extensions Arms T-Arms

Significant EPA differences

Mount Options


8/16



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 obstructionsthat are less than 30 tall.

Exposure D : Structure is in flat, unobstructed shoreline exposed to wind flowing overopen 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 forservices that are optional. I.E. Ham Radio Tower

Class 2 (I=1.0) (default): Structures that due to height, use or location represent asubstantial hazard to human life and damage to property in the event of a failureand/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 forprimary communication. I.E. Emergency Response Tower



Dish Specifications

Sway Requirements based on dishfrequency and dish size

The higher the frequency the stricter

the twist and sway requirements



Steps to competitive and proper designs

Well written specificationsContact Valmont Industries for all yourspecification questions and concerns.

Provide any clarification to all manufacturersReview designs

Ensure that specifications are adhered to

If base reactions are significantly different thereis a difference in specification interpretation



Steps to competitive and proper designs14

The lowest price doesnt always meet yourneeds.

Did you get what you wanted?


15/16


Questions15


16/16



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 numerousclosely spaced obstructions having the size of single-family dwellings or larger. Use ofthis exposure shall be limited to those areas for which terrain representative ofExposure 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 lessthan 30 tall (9.1m). This category includes flat, open country, grasslands andshorelines in hurricane prone regions.

Exposure D : Structure is in flat, unobstructed shoreline exposed to wind flowing overopen water (excluding hurricane prone regions) for a distance of at least 1 mile (1.61km). Shorelines in Exposure D include inland waterways, lakes and non-hurricanecoastal areas. Exposure D extends inland a distance of 660 ft (200 m) or ten timesthe height of the structure, whichever is greater. Smooth mud flats, salt flats and othersimilar terrain shall be considered as Exposure D.

Krohn_valmont_TIA.pdf

Documents