davies_get the most out of your tower_excelente presentacion sobre torres y normas tia contexto...

7/29/2019 Davies_GET the MOST OUT of YOUR TOWER_Excelente Presentacion Sobre Torres y Normas TIA Contexto Historico y Cambios

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EFFECTIVELY USING DESIGN STANDARDS TO YOURFFECTIVELY USING DESIGN STANDARDS TO YOURADVANTAGEDVANTAGE

David K. DaviesDavid K. DaviesCEICEI

Consolidated Engineering,Consolidated Engineering,IncInc

P.O. Box 4203P.O. Box 4203Evansville, Indiana 47724Evansville, Indiana 47724

This presentation is the work product of CEI. Reproduction, transmission or disclosure to others, or unauthorized use without the

expressed written consent of CEI is prohibited and a violation of Federal Law

GET THE MOST OUT OFGET THE MOST OUT OFYOUR TOWERYOUR TOWER

Electronics Research, Inc.

7777 Gardner Rd. Chandler, IN 47610

SPONSORED BY


2/66

QUESTIONS!?!QUESTIONS!?!

Recent eventsnecessitate a newantenna installation ona 30 year old tower.You begin to wonder

HOW DO IHOW DO I

PROCEED?PROCEED?

WHERE DOWHERE DOI BEGIN?I BEGIN?


3/66

LOCALLOCALBUILDINGBUILDING

AUTHORIAUTHORITY?TY?

WHOWHOs GOING TO CARE?s GOING TO CARE?

YOURYOUR

INSURANCEINSURANCEPROVIDER?PROVIDER?

YOUR NEIGHBORS,YOUR NEIGHBORS,MOST OF WHOM SEEMMOST OF WHOM SEEM

TO BE ATTORNEYS?TO BE ATTORNEYS?

TOWER SPACETOWER SPACERENTER?RENTER?


4/66

Several factors musteveral factors mustbe taken intoe taken intoconsideration.onsideration.Maybe just aaybe just a

DESIGN STANDARDESIGN STANDARDis all thats all thats necessarynecessary

GEE, I HAD BETTER MEET THEGEE, I HAD BETTER MEET THE

CODE!!!CODE!!!Or, maybeOr, maybe

NOT?NOT?


5/66

DESIGN CODES ARE MANDATORYCode is short for Codification, i.e. formalizing the laws ofjurisdiction by setting them out in a book or law or codex.

Design Codes are formulated by the LegislativeBranch, enforced by the Executive Branch andsometimes reviewed by the Judicial Branch ofGovernment.

DESIGN CODE or DESIGN STANDARDDESIGN CODE or DESIGN STANDARD

DO YOU KNOW THE DIFFERENCE?DO YOU KNOW THE DIFFERENCE?


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THE RELATIONSHIP IS TYPICALLY A FUNCTION OFHE RELATIONSHIP IS TYPICALLY A FUNCTION OFLOCAL OR STATE GOVERNMENTOCAL OR STATE GOVERNMENT

CODES AND TOWERSCODES AND TOWERS

Examples:xamples:Southern States Building Codesouthern States Building CodesFlorida Building Codelorida Building CodeDillard Building Codeillard Building CodeBOCAOCAUBCBC Unified Building Codenified Building CodeIBCBC

International Building Codenternational Building Code


7/66

DESIGN STANDARDS ARE VOLUNTARYESIGN STANDARDS ARE VOLUNTARYSTANDARDS detail engineering methods and/orspecifications promulgated by Public or Private

organizations.

STANDARDS direct engineers and technicians inusing methods specified for in the designprocess.

DESIGN STANDARDSDESIGN STANDARDS


8/66

For the past 60 years, the EIA,TIA, and ANSIOrganizations have provided Tower DesignStandards with the stated purpose of:

TOWER DESIGN STANDARDSTOWER DESIGN STANDARDS

1.

Eliminating misunderstanding betweenmanufacturers and purchasers2.

Assist the purchaser in selecting andobtaining the proper product for hisparticular need


9/66

STANDARDS CAN BE FOUNDSTANDARDS CAN BE FOUND

WITHIN THE CODESWITHIN THE CODES

A Tower Design Code may include oneof the Tower Design Standards. If so, itMUST be applied without variation.

IBC 2000IBC 2000

TIA/EIA 222 ETIA/EIA 222 E

IBC 2003IBC 2003

TIA/EIA 222 FTIA/EIA 222 F

IBC 2006IBC 2006

TIA/EIA 222 FTIA/EIA 222 F

IBC 2009IBC 2009

ANSI/TIA 222 GANSI/TIA 222 G


10/66

DETERMINE WHAT YOUDETERMINE WHAT YOURE TRYING TORE TRYING TOACHIEVEACHIEVE

YOURYOUR FIRSTFIRST DECISIONDECISION

Is your primary goal to satisfys your primary goal to satisfyBuilding Permit Requirements (uilding Permit Requirements (ieelocal codesocal codes)??Is it the towers it the towers CAPACITY you needCAPACITY you needto determine?o determine?

Or, do you just want tor, do you just want to getet er doner done?

Which

path do Itake?


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IF aF a BUILDING PERMITUILDING PERMITis required, meetings required, meetingthehe CURRENTURRENTDESIGN CODEESIGN CODE of thisf thisjurisdiction may beurisdiction may bemandatory.andatory.

MEETING BUILDING CODEMEETING BUILDING CODE

REQUIREMENTSREQUIREMENTS


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YOUR ONLY REQUIREMENT IN SOMEYOUR ONLY REQUIREMENT IN SOME

SITUATIONS MAY BE:SITUATIONS MAY BE:

VERIFICATION OF THE TOWERS STRUCTURALCAPACITYVERIFYING TOWER STRENGTH REQUIRES PROOF YOUERIFYING TOWER STRENGTH REQUIRES PROOF YOURE COMPLYINGE COMPLYINGWITHITH A STANDARD, NOT NECESSARILY A SPECIFIC STANDARDTANDARD, NOT NECESSARILY A SPECIFIC STANDARD

This allows the owner maximum flexibility in determining which Dhis allows the owner maximum flexibility in determining which DesignsignStandard best fits his needs and how it shall be applied.tandard best fits his needs and how it shall be applied.

VERIFYING TOWER CAPACITYVERIFYING TOWER CAPACITY


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STRUCTURAL ANALYSIS ISSTRUCTURAL ANALYSIS ISTHETHE METHOD FORMETHOD FORDETERMINING A TOWERDETERMINING A TOWERS CAPACITYS CAPACITYVERIFYING TOWER CAPACITYVERIFYING TOWER CAPACITY

Structural Analysistructural Analysisusing asing aDesign Standardesign Standardwill assist the purchaserill assist the purchaserin achieving hisn achieving his goaloal orrobjectivebjective.

C O O O


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Proposed antenna change

Proposed tower modificationRequirement to obtain or retain insurance

Potential tower space rental requirement

Address public concernGeneral Liability purposes

VERIFICATION OF TOWERVERIFICATION OF TOWER

CAPACITYCAPACITY

HELPFUL OR NECESSARY UNDER THEHELPFUL OR NECESSARY UNDER THEFOLLOWING CONDITIONS:FOLLOWING CONDITIONS:


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WHICH TYPE OF STRUCTURAL ANALYSISWHICH TYPE OF STRUCTURAL ANALYSISIS BESTIS BEST--SUITED FOR MY NEEDS?SUITED FOR MY NEEDS?

DECICION #2DECICION #2

FEASIBILITY ANALYSISEASIBILITY ANALYSISINVESTIGATES THE MAINSTRUCTURAL MEMBERSAND OVERALL STABILITYOF THE STRUCTURE

RIGOROUS ANALYSISIGOROUS ANALYSISEVALUATES ALLSTRUCTURAL MEMBERS,

CONNECTIONS ANDFOUNDATIONS


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Bases your decisionases your decisionwithith yourour

goal inoal inmindind-Donont be swayed bybe swayed bywhat the towerhat the tower

manufacturer oranufacturer orconsulting engineeronsulting engineerwants to sell you!ants to sell you!

FEASABILITY OR RIGOROUSFEASABILITY OR RIGOROUS

ANALYSISANALYSISTHE DECISION ISTHE DECISION ISYOURS!YOURS!


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Adhering to the Design Standard useddhering to the Design Standard usedduring the construction of your toweruring the construction of your towermay be advantageousay be advantageousBUT NOTUT NOTALWAYS!LWAYS!

After reviewing the Standards,fter reviewing the Standards, bothoth theheadvantagesdvantagesandnd disadvantagesisadvantages will be apparentill be apparent

DECICION #3DECICION #3

CHOOSING WHICH DESIGN STANDARD TOCHOOSING WHICH DESIGN STANDARD TOIMPLEMENTIMPLEMENT

t


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ORIGINAL FAMILY:ORIGINAL FAMILY:

EIAEIA--RSRS--222222

(A, B and C)(A, B and C) THETHE Standard until 1987Standard until 1987SECOND FAMILY:SECOND FAMILY: TIA/EIATIA/EIA--222222(D, E, and F)(D, E, and F) used until 2006used until 2006THIRD FAMILY:THIRD FAMILY: ANSI/TIA 222 Rev GANSI/TIA 222 Rev Gbecame THE in 2006became THE in 2006

o t eo eMEET THE FAMILIESMEET THE FAMILIES


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RUDIMENTARY COMPARED TOUDIMENTARY COMPARED TOLATER STANDARDSATER STANDARDSTHEHE C-STANDARDTANDARD HAD ITS

AD ITSSHORTCOMINGS, YETHORTCOMINGS, YETADVANTAGES, AS WELL,DVANTAGES, AS WELL,DEPENDING UPON ONEEPENDING UPON ONESPERSPECTIVE AND OBJECTIVEERSPECTIVE AND OBJECTIVE

EIA/RS 222EIA/RS 222--C FAMILYC FAMILY


20/66

ICE ACCUMULATIONCE ACCUMULATION on tower members andappurtenances NOT MENTIONEDOT MENTIONED TOPOGRAPHICAL FEATURESOPOGRAPHICAL FEATURES and the effect ofincreased wind force NOT MENTIONEDOT MENTIONED LOWER WIND VELOCITYOWER WIND VELOCITY (force) than upcomingStandards WIND SHIELDINGIND SHIELDING at engineers discretion SOIL DESIGN PARAMETERSOIL DESIGN PARAMETERS extremely liberal

EIA/RS 222EIA/RS 222--C FAMILYC FAMILY


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CONFLICTED WITH NEWLYONFLICTED WITH NEWLYEVOLVING BUILDINGVOLVING BUILDINGCODESODES

EIA/RS 222EIA/RS 222--C STANDARDSC STANDARDS

ASSOCIATED PROBLEMSASSOCIATED PROBLEMS

CONSEQUENCES:ONSEQUENCES: BUILDING PERMITS QUESTIONED and/orUILDING PERMITS QUESTIONED and/or DENIEDENIED


22/66

Tower manufacturersower manufacturersrealized the urgency toealized the urgency torevampevamp theheRS FAMILY OFS FAMILY OFSTANDARDS to complyTANDARDS to comply

with the newly authoredith the newly authoredAmerican Nationalmerican NationalStandard (ANSI) A58.1:tandard (ANSI) A58.1:Minimum Design Loadsinimum Design Loadsfor Buildings and Otheror Buildings and OtherStructurestructures

EIA/RS 222EIA/RS 222--C EVOLVESC EVOLVES


23/66

FROM EIA/RS 222FROM EIA/RS 222--CC

to TIA/EIA 222to TIA/EIA 222--FF

Despite a major overhaul, the statedespite a major overhaul, the statedintent remained unchanged:ntent remained unchanged:

" To assist the tower owner inTo assist the tower owner inobtaining a proper product forbtaining a proper product forhis particular need.is particular need.


24/66

GENERALLY SPEAKINGGENERALLY SPEAKING,,

SUBSEQUENT REVISIONS BECAMESUBSEQUENT REVISIONS BECAMEMOREMORE STRINGENTSTRINGENT

ANOTHER EXAMPLE OFANOTHER EXAMPLE OFADVANTAGESADVANTAGESANDAND DISADVANTAGESDISADVANTAGES,, DEPENDING ONDEPENDING ON

YOUR GOAL AND PERSPECTIVEYOUR GOAL AND PERSPECTIVE

BUT NOT FOR EVERY CASE OR IN ALL GEOGRAPHICUT NOT FOR EVERY CASE OR IN ALL GEOGRAPHICAREASREAS


25/66

THETHE FF

FAMILY,FAMILY, OR STANDARDOR STANDARD,,

BROUGHT MAJOR CHANGESBROUGHT MAJOR CHANGESREGARDING WIND SPEED/PRESSUREREGARDING WIND SPEED/PRESSURE

SPECIFICATIONSSPECIFICATIONS

1) WIND VELOCITY REPLACED THEOUTDATED POUNDS PER SQUARE FOOT IND PRESSURE2) FASTEST MILE WAS INTRODUCED

3) D INCLUDED A MAP, E AND F MPLEMENTED A COUNTY BY COUNTYLISTING


26/66

SOME WIND FORCES PER AREA WERESOME WIND FORCES PER AREA WERE

INCREASED, OTHER WEREINCREASED, OTHER WERE NOTNOT

RS 222 AS 222 A-CPSFSF

TIA/EIA 222 DIA/EIA 222 D-FFASTEST MILEASTEST MILE


27/66

INTRODUCINGINTRODUCINGICEICE!!

COURTESY OF THECOURTESY OF THEFF FAMILYFAMILYTHEHE F FAMILY WAS THE FIRST TO ADDRESSAMILY WAS THE FIRST TO ADDRESSTHE EFFECTS OF ICE ACCUMULATION ON THE TOWERHE EFFECTS OF ICE ACCUMULATION ON THE TOWER

AND APPURTENANCES AND INCLUDED A METHOD FORND APPURTENANCES AND INCLUDED A METHOD FORCALCULATING THE ADDITIONAL LOADINGALCULATING THE ADDITIONAL LOADINGConsideration for ICE was stillonsideration for ICE was still optionalptional

and the responsibilitynd the responsibility

of thef thePURCHASERURCHASER as to whether it was included in the designs to whether it was included in the designSuggesteduggested

(evenly applied) radial ice with 13%evenly applied) radial ice with 13%

a reduced wind velocityreduced wind velocityDesigners were instructed to factor foresigners were instructed to factor for AREAREA ONLYNLY , not thenot theadditionaldditionalweighteight of ICE; The Standard does recognize that ice may be af ICE; The Standard does recognize that ice may be asignificantignificantload for structures to be located in areas of significant iceoad for structures to be located in areas of significant ice


28/66

MOREMOREFF

FEATURES & INCLUSIONSFEATURES & INCLUSIONS

Topographic Features and increased Wind Velocityopographic Features and increased Wind Velocitywere introduced but not mandatory in the designere introduced but not mandatory in the design

Wind speed was increase with height of tower butind speed was increase with height of tower buteach revision used different methodsach revision used different methods

Wind Shielding could vary from 35% to 65%ind Shielding could vary from 35% to 65%

Bothoth C

Standards andtandards and F

Standards used antandards used anAllowable Stressllowable Stress

design method but theesign method but the Ftandards allowed a 1/3 increase above thetandards allowed a 1/3 increase above thefactored memberactored members strengthstrength


29/66

FF FAMILY OF STANDARDS CONTINUEDFAMILY OF STANDARDS CONTINUEDSAFETY FACTORSSAFETY FACTORS

THEHE F

STANDARD REDUCED THE DESIGN SAFETY FACTORTANDARD REDUCED THE DESIGN SAFETY FACTORFROM THEROM THE PREVIOUSREVIOUS MAXIMUM OF 2.5, MANDATED IN THEAXIMUM OF 2.5, MANDATED IN THE CTANDARDTANDARD

CONCERNINGONCERNING F, SAFETY FACTORS VARIED AS A FUNCTIONSAFETY FACTORS VARIED AS A FUNCTIONOF TOWER HEIGHT AND MEMBER FUNCTION. SOME WERE ASF TOWER HEIGHT AND MEMBER FUNCTION. SOME WERE ASLOW AS 1.6OW AS 1.6SOIL DESIGN PARAMETERS REMAINED VERY LIBERAL BUTOIL DESIGN PARAMETERS REMAINED VERY LIBERAL BUTSOME RESTRICTIONS WERE IMPOSED ON THE PREVIOUSOME RESTRICTIONS WERE IMPOSED ON THE PREVIOUSDESIGN METHODSESIGN METHODS

A SAFETY FACTOR IS THE RATIO OF LOAD CAPACITY

TO APPLIED LOAD

y ey e


30/66

y ey eAMERICAN SOCIETY OF CIVILAMERICAN SOCIETY OF CIVIL

ENGINEERSENGINEERSJust when we were comfortable using theust when we were comfortable using the

Fastest Mileastest Mile wind speed calculation, ASCEind speed calculation, ASCE-7WIND VELOCITIES started gaining popularityIND VELOCITIES started gaining popularityfor building and other structures designs.or building and other structures designs.Most Planning and Review Boards wereost Planning and Review Boards wereaccustomed to seeing higher wind speeds thanccustomed to seeing higher wind speeds thanthehe fastest mileastest mile

average presented, creatingverage presented, creatingadditional problems for new tower applications.dditional problems for new tower applications.

FASTEST MILE TO PEAK 3FASTEST MILE TO PEAK 3 SECOND GUSTSECOND GUST


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FASTEST MILE TO PEAK 3FASTEST MILE TO PEAK 3--SECOND GUSTSECOND GUST

COMPARISON & CONVERSIONCOMPARISON & CONVERSION


32/66

ANSI/TIA/EIAANSI/TIA/EIA--222 REV G222 REV G

THE INDUSTRYTHE INDUSTRYS MOST SWEEPING CHANGES MOST SWEEPING CHANGEREVISION GEVISION G , THE MOST COMPREHENSIVE CHANGE TO THETHE MOST COMPREHENSIVE CHANGE TO THESTANDARD SINCE ITS FIRST PUBLICATION IN 1949,TANDARD SINCE ITS FIRST PUBLICATION IN 1949,INTRODUCED NEW VARIABLES FOR CONSIDERATION IN THENTRODUCED NEW VARIABLES FOR CONSIDERATION IN THEDESIGN OF BROADCAST TOWERS.ESIGN OF BROADCAST TOWERS.DESIGN CRITERIA NOW BASED ONESIGN CRITERIA NOW BASED ON SITEITE-SPECIFICPECIFIC VARIABLESARIABLESRATHER THAN GENERIC CRITERIA USED IN PREVIOUSATHER THAN GENERIC CRITERIA USED IN PREVIOUSADDITIONS TO THE STANDARD.DDITIONS TO THE STANDARD.REV G POSES ADDITIONAL CHALLENGES FOR EXISTINGEV G POSES ADDITIONAL CHALLENGES FOR EXISTINGBROADCAST TOWERS.ROADCAST TOWERS.

ANOTHER MAJOR ELEMENT OF THIS STANDARD IS THENOTHER MAJOR ELEMENT OF THIS STANDARD IS THEBURDEN OF RESPONSIBILITY IN MANY AREAS HAS BEENURDEN OF RESPONSIBILITY IN MANY AREAS HAS BEENTRANSFERRED FROM THE PURCHASER OR OWNER TO THERANSFERRED FROM THE PURCHASER OR OWNER TO THEDESIGNING ENGINEER(S).ESIGNING ENGINEER(S).


33/66

EMPLOYED ASCE 7 WIND AND ICE

PREDICTIONS: 3-Second Gust replacedFastest Mile

EXPOSURE (Terrain Roughness)

Categories included

TOPOGRAPHY and resultant Wind-

speedup

COUNTY by COUNTY WIND AND ICE MAPS


HIGHLIGHTSHIGHLIGHTS


34/66


WIND SPEED MAPWIND SPEED MAP



35/66

ANSI/TIA/EIAANSI/TIA/EIA--222 REV G222 REV GTOPOGRAPHIC CATEGORIESTOPOGRAPHIC CATEGORIES

INCREASE VARIES WITH TYPE AND

SIZE OF TOPOGRAPHIC FEATURE

INCREASE VARIES WITH TYPE AND

SIZE OF TOPOGRAPHIC FEATURE



36/66

ANSI/TIA/EIAANSI/TIA/EIA--222 REV G222 REV GEXPOSURE CATEGORIESEXPOSURE CATEGORIES

Exposure C: Open Terrain

Exposure B: Smaller Building and Trees

Exposure D: Unobstructed Shorelines

Another example of tower design

variables not mandated in previous

Design Standards. Exposure categoriesrelate to ground roughness which may

affect wind velocity by reducing or

increasing the wind speed, deviating from

the wind velocity specified in Appendix B

of Rev G.

ANSI/TIA/EIA 222 REV G


37/66


ADDITIONAL FEATURESADDITIONAL FEATURES

NO 1/3 INCREASE IN MEMBER STRENGTHO 1/3 INCREASE IN MEMBER STRENGTHALLOWEDLLOWED

ELIMINATESLIMINATES NORMAL SOILORMAL SOIL and replaces it withnd replaces it withmore conservative, explicit definitionsore conservative, explicit definitions

OWNERS can specify IMPORTANCE FACTORS orWNERS can specify IMPORTANCE FACTORS orCONSEQUENCE OF FAILURE FACTOR which mayONSEQUENCE OF FAILURE FACTOR which mayreduce or increase design forceseduce or increase design forces

C C O O CCLASSIFICATION OF STRUCTURES


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CLASSIFICATION OF STRUCTURESCLASSIFICATION OF STRUCTURES

REV GREV G


39/66

REV GREV GCLASS AND IMPORTANCE FACTORSCLASS AND IMPORTANCE FACTORS

CLASS ILASS I25 year return Period:5 year return Period: Same asame as C

Standard.tandard.Importance Factor = 0.87mportance Factor = 0.87x wind pressurewind pressureCreates a wind pressure that isreates a wind pressure that is13% less than Class II, (7% decrease in wind speed)3% less than Class II, (7% decrease in wind speed)24% less than Class III (13% decrease in wind speed)4% less than Class III (13% decrease in wind speed)

CLASS IILASS II50 year return Period:0 year return Period: Same asame as F Standard.tandard.Importance Factor = 1.00mportance Factor = 1.00 x wind pressurewind pressureCreates a wind pressure that isreates a wind pressure that is13% Greater than Class I, (7% increase in wind speed)3% Greater than Class I, (7% increase in wind speed)15% less than Class III, (7% decrease in wind speed)5% less than Class III, (7% decrease in wind speed)CLASS IIILASS III100 year return Period:00 year return Period:Importance Factor = 1.15mportance Factor = 1.15 x wind pressurewind pressureCreates a wind pressure that isreates a wind pressure that is13% Greater than Class II, (7% increase in wind speed)3% Greater than Class II, (7% increase in wind speed)24% Greater than Class I (13% increase in wind speed)4% Greater than Class I (13% increase in wind speed)


40/66

CC--GG WIND FORCE COMPARISONWIND FORCE COMPARISONUSING A 400USING A 400 TOWERTOWER

C StandardStandard

F StandardStandard

G StandardStandardClass IIlass II

30 psf0 psf

73 mph3 mph

83 mph3 mph40 psf0 psf

84 mph4 mph

95 mph5 mph50 psf0 psf

95 mph5 mph

107 mph07 mph


41/66

EVOLVING WIND FORCESEVOLVING WIND FORCES

FAMILYFAMILY MAP COMPARISONMAP COMPARISONC::PSFSF

F:FASTEST MILE:FASTEST MILE

G::3 SEC GUSTEC GUST

CC GG COMPARISONCOMPARISON


42/66

CC GG COMPARISONCOMPARISONIceIce

C STANDARD:STANDARD:

Noomention, not requiredention, not requiredF STANDARD:STANDARD:

Nototrequired, but if usedequired, but if used

ce at 87% of design windce at 87% of design windspeedpeedG STANDARD:STANDARD: Mandatedandatedwith included ice map andith included ice map andreduced wind speed of 30educed wind speed of 30or 40 mphr 40 mph

REV G WIND & ICE MAPREV G WIND & ICE MAP


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REV G WIND & ICE MAPREV G WIND & ICE MAP

22222-G WIND & ICEWIND & ICE

CC GG COMPARISONCOMPARISON


44/66

CC GG COMPARISONCOMPARISONSafety Factor and Member StrengthSafety Factor and Member Strength

1.. C STANDARD:TANDARD: Safety Factors ranged from 2.5 forafety Factors ranged from 2.5 forguy wire to 2.0 for steel,uy wire to 2.0 for steel, no 1/3 increase in membero 1/3 increase in memberstrengthtrength2.. F STANDARD:TANDARD: Safety Factors ranged from 2.0 toafety Factors ranged from 2.0 to1.6, and also 1/3 increase in member strength.6, and also 1/3 increase in member strengthallowed. (1.5 to 1.2)llowed. (1.5 to 1.2)3.. G STANDARD:TANDARD: No Safety Factors per seo Safety Factors per se , butbutwould range from 1.7 to 2.0,ould range from 1.7 to 2.0, no 1/3 increase ino 1/3 increase inmember strength allowedember strength allowed

WHICH STANDARD IS BESTWHICH STANDARD IS BEST SUITEDSUITED


45/66

WHICH STANDARD IS BESTWHICH STANDARD IS BEST--SUITEDSUITEDFOR ACHIEVING YOUR GOAL?FOR ACHIEVING YOUR GOAL?

1))

WHAT IS YOUR OBJECTIVE?HAT IS YOUR OBJECTIVE?2))

WHAT WAS THE ORIGINAL DESIGN STANDARD?HAT WAS THE ORIGINAL DESIGN STANDARD?

3))

WHAT ARE THE CONSEQUENCES OF FAILURE?HAT ARE THE CONSEQUENCES OF FAILURE?

USING THE STANDARDS TOUSING THE STANDARDS TO


46/66


ACHIEVE YOUR GOALACHIEVE YOUR GOAL#1 DEFINING YOUR OBJECTIVE#1 DEFINING YOUR OBJECTIVE

BUILDING PERMITUILDING PERMITESTABLISH TOWER CAPACITYSTABLISH TOWER CAPACITYJUSTUST GETET ER DONER DONE

1. Antenna up?. Antenna up?2. Insurance purchased?. Insurance purchased?3. Neighbors appeased?. Neighbors appeased?



47/66


ACHIEVE YOUR GOALACHIEVE YOUR GOAL

#2 WHAT WAS THE ORIGINAL DESIGN#2 WHAT WAS THE ORIGINAL DESIGNSTANDARD?STANDARD?MOSTOST C

TOWERS CAN MEETOWERS CAN MEET F

ANALYSIS w/o ICE andNALYSIS w/o ICE and G

NALYSIS in minimal icing areasNALYSIS in minimal icing areasMOSTOST F

TOWERS w/ICE CAN MEETOWERS w/ICE CAN MEET G

ANALYSISNALYSIS

MOSTOST F

TOWERS w/o ICE CANNOT MEET aOWERS w/o ICE CANNOT MEET a G

AnalysisnalysisUnless these are adjustednless these are adjusted1. AREAAREA -SPECIAL WIND SPEEDPECIAL WIND SPEED2. ICE PREDICTIONS PER ASCE. ICE PREDICTIONS PER ASCE3. EXPOSURE. EXPOSURE

COMPARING THE STANDARDSCOMPARING THE STANDARDS


48/66

COMPARING THE STANDARDSCOMPARING THE STANDARDSLOADINGLOADING

EXAMPLE: 350XAMPLE: 350

UTILITYTILITY

GUYED TOWERUYED TOWER(TYPICAL FM TOWERYPICAL FM TOWER )

DESIGNED USING:ESIGNED USING: C

STANDARD,TANDARD,NO ICEO ICEANALYZED USING:NALYZED USING:)) F STANDARDTANDARD2))

G

STANDARDTANDARD

COMPARISONCOMPARISON


49/66

COMPARISONCOMPARISONFF

STANDARD NO ICE AND ICESTANDARD NO ICE AND ICE

75 MPH NO ICE75 MPH NO ICE andand 65 MPH WITH65 MPH WITH ICEICE

OVEROVER--STRESSEDSTRESSED

COMPARISONCOMPARISON


50/66

COMPARISONCOMPARISONGG

STANDARD NO ICE AND ICESTANDARD NO ICE AND ICE

90 MPH NO ICE90 MPH NO ICE andand 40 MPH WITH 3/440 MPH WITH 3/4 ICEICE


COMPARINGCOMPARING FF STANDARD ICESTANDARD ICE


51/66

COMPARINGCOMPARING FF STANDARD ICESTANDARD ICEWithWith GG STANDARD ICESTANDARD ICE

GGWITH ICEWITH ICEFFWITH ICEWITH ICE


FURTHER CONSIDERATIONSFURTHER CONSIDERATIONS


52/66

FURTHER CONSIDERATIONSFURTHER CONSIDERATIONS

MOST TOWERS DESIGNED TO THEOST TOWERS DESIGNED TO THE F TANDARD, WITHOUT ICE, CANNOTTANDARD, WITHOUT ICE, CANNOTMEET THEEET THE G STANDARD WITHOUTTANDARD WITHOUTADDITIONAL CONSIDERATIONSDDITIONAL CONSIDERATIONS1.. AREAREA-SPECIFIC WIND SPEEDPECIFIC WIND SPEED2.. ICE PREDICTIONS,CE PREDICTIONS, PER ASCEER ASCE

3.. EXPOSUREXPOSURE

FOUR WIND CONTOURS FOUND WITHINFOUR WIND CONTOURS FOUND WITHIN


53/66

FOUR WIND CONTOURS FOUND WITHINFOUR WIND CONTOURS FOUND WITHINTHETHESAMESAME

COUNTYCOUNTY

1

2 3

4

ASCE WIND SPEED MAP WITH ICEASCE WIND SPEED MAP WITH ICE


54/66

ASCE WIND SPEED MAP WITH ICEASCE WIND SPEED MAP WITH ICE

WIND SPEED (MPH) WITH ICE AND DESIGNIND SPEED (MPH) WITH ICE AND DESIGN -ICE THICKNESSCE THICKNESSSTANDARDSTANDARDS

EXPOSUREEXPOSURE


55/66

EXPOSUREEXPOSUREGROUND ROUGHNESS REDUCESGROUND ROUGHNESS REDUCES

WIND VELOCITY AND FORCEWIND VELOCITY AND FORCE

LESS VELOCITY AND FORCE MORE VESS VELOCITY AND FORCE MORE VELOCITY AND FORCELOCITY AND FORCE



56/66


ACHIEVE YOUR GOALACHIEVE YOUR GOAL#3 THE CONSEQUENCES OF FAILURE#3 THE CONSEQUENCES OF FAILURE

CLASS 1: POSES LITTLE RISK TO HUMAN LIFELASS 1: POSES LITTLE RISK TO HUMAN LIFEIMPORTANCE FACTOR = 0.87IMPORTANCE FACTOR = 0.87 x WIND PRESSUREx WIND PRESSURE

CREATES A WIND PRESSURE THAT IS:REATES A WIND PRESSURE THAT IS:1)1)

13% LESS THAN CLASS II, (7% DECREASE IN13% LESS THAN CLASS II, (7% DECREASE INWIND SPEED)WIND SPEED)

2)2)

24% LESS THAN CLASS III (13% DECREASE IN24% LESS THAN CLASS III (13% DECREASE IN

WIND SPEED)WIND SPEED)

TOWER MODIFICATION ANDTOWER MODIFICATION AND


57/66

THETHELEASTLEAST DESIRABLE OUTCOME OFDESIRABLE OUTCOME OFANALYSISANALYSISRECALL THE OBJECTIVES OFECALL THE OBJECTIVES OFSTRUCTURAL ANALYSIS:TRUCTURAL ANALYSIS:

1.. TO VERIFY THE TOWERO VERIFY THE TOWERS CAPACITYCAPACITY2.. ASSIST THE OWNER IN OBTAININGSSIST THE OW NER IN OBTAININGTHEHEAPPROPRIATE PRODUCT(S) TOPPROPRIATE PRODUCT(S) TOMEET HISEET HISSPECIFIC NEEDS/REQUIREMENTSPECIFIC NEEDS/REQUIREMENTS

TOWER MODIFICATION ANDTOWER MODIFICATION AND

REINFORCEMENTREINFORCEMENT

THE 3 MOST VOLITILE FACTORSTHE 3 MOST VOLITILE FACTORS


58/66


ININ REINFORCINGREINFORCING--DESIGNDESIGN COSTCOST1.. WIND SHIELDINGIND SHIELDING2.. INITIAL GUY WIRE TENSIONNITIAL GUY WIRE TENSION3..

METHODS OF REINFORCINGETHODS OF REINFORCING



59/66


ININ REINFORCINGREINFORCING--DESIGNDESIGN COSTCOSTWIND SHIELDINGWIND SHIELDINGCan vary from 0 to 100% depending uponDesign Standard and the engineersdiscretion.

Unfortunately, its not uncommon for a tower

to be designed and sold using a highamountof wind shielding.

Then later Analyzed by same company using

a loweramount of shielding, the tower nowappears to require reinforcing.

HOW WOULD YOU KNOW?OW W OULD YOU KNOW?



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ININ REINFORCINGREINFORCING--DESIGNDESIGN

COSTCOST

INITIAL GUY WIRE TENSIONINITIAL GUY WIRE TENSION(GUY WIRE PRE(GUY WIRE PRE--TENSION)TENSION)

TYPICALLY, 10% OF BREAKING STRENGTH IN NEWYPICALLY, 10% OF BREAKING STRENGTH IN NEWDESIGNS, BUT MAY VARY FROM 8% TO 15%ESIGNS, BUT MAY VARY FROM 8% TO 15%

INITIAL GUY WIRE TENSIONINITIAL GUY WIRE TENSION


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DEFLECTION GRAPH OF TOWER UNDER LOADDEFLECTION GRAPH OF TOWER UNDER LOAD

Before Adjustments

After Adjustments



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CHANGES IN INITIAL TENSION OF GUYSCHANGES IN INITIAL TENSION OF GUYS

EXISTING GUY INITIAL TENSIONSXISTING GUY INITIAL TENSIONS

NEW GUY INITIAL TENSIONSEW GUY INITIAL TENSIONS



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ININ REINFORCINGREINFORCING--DESIGNDESIGN

COSTCOST

METHODS OF REINFORCINGMETHODS OF REINFORCING

MOST REINFORCING METHODS ARE THEORETICAL AND WITHOUT TESTOST REINFORCING METHODS ARE THEORETICAL AND WITHOUT TESTDATA OR DOCUMENTATION TO VERIFY IMPROVEMENT TO MEMBERATA OR DOCUMENTATION TO VERIFY IMPROVEMENT TO MEMBERSTRENGTH.TRENGTH.

WHEN FACED WITH A $250,000.00HEN FACED WITH A $250,000.00REINFORCING PROJECT, IT NEVER HURTS TOEINFORCING PROJECT, IT NEVER HURTS TOGET A $2,500.00 SECOND OPINION.ET A $2,500.00 SECOND OPINION.

ASK SOMEONE WHO KNOWS!ASK SOMEONE WHO KNOWS!


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ASK SOMEONE WHO KNOWS!ASK SOMEONE WHO KNOWS!

VERIFY WITH ACTUAL TESTING DATAVERIFY WITH ACTUAL TESTING DATA

REVIEWING A REINFORCING DESIGNREVIEWING A REINFORCING DESIGN


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REVIEWING A REINFORCING DESIGNREVIEWING A REINFORCING DESIGN

ASK YOURSELF THE FOLLOWINGASK YOURSELF THE FOLLOWING

QUESTIONS:QUESTIONS:

AM I USING THE BEST SUITED DESIGNM I USING THE BEST SUITED DESIGNSTANDARD?TANDARD?

AM I USING ALL OF THE ADVANTAGESM I USING ALL OF THE ADVANTAGESOFFERED BY THAT STANDARD?FFERED BY THAT STANDARD?AM I GETTING THE MOST ECONOMICALM I GETTING THE MOST ECONOMICALDESIGN OR MERELY BUYING STEEL?ESIGN OR MERELY BUYING STEEL?


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For additional information concerning ourproducts and serv ices contact :

DAVID K. DAVIESDAVID K. [email protected]

CEI

CONSOLIDATED

ENGINEERING, INC

P.O. BOX 4203

EVANSVILLE, INDIANA 47724-4203+1 (812) 459-1341
mailto:[email protected]:[email protected]

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