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<br />, FILE No. 375 09/13 '96 08:11 ID:SPRINT SPECTRUM MPLS <br /> <br />6126862700 <br /> <br />PAGE 2 <br /> <br />SEP. 12. 1996 4:43PM COMM rWR 4ez 359 5856 <br /> <br />NO. 655 P.2/4 <br /> <br /> <br />~lmor.t IndU&lrlGi, InCL. WeQI Highway 275 . P;O. Box 358 <br />Wley. NBbras1<a e8Q64-03S6 U.aA. . (402) 369.2201 <br /> <br />Septesnber 12, 1996 <br /> <br />sprint Spectrum <br />2900 Lone Oak Pkwy . <br />Suite 140 <br />Ragan, MN 55121 <br /> <br />Attention: Mr. Dave Riaan <br /> <br />Subject: FallurB Mndes ft.! Poles and a Description oftha Deslgn CrJ:teria <br />SprInt Spectrum. MinnespotIs. MN <br /> <br />Dear Mr. Hagan: <br /> <br />I have been asked to write to you about the mode ofthUure for pole type ~tures used <br />to auppart cellu1ar anten:nliS and equipment. and give some lofbrmation to ellowyou to <br />judge how remote the chances offallure occuning woukfbc. I think it would be <br />appropriate to start oft'by a briflf degcr}ptlon oftbo desIgn crIteria that is typIcally used. <br /> <br />The plIes Valmont Jupplba are designed in aooordance with El.A.II'l.A. 222 Revision Ii <br />Standard eIl1itled "Structural Standards for Steel Antem3A Towers and Antenna <br />Supporting Structures." This is an approved AN.S.I. standard that has dealt with the <br />design of lattIce type S'tnU:tures fur a I1WDber of rears. ~v:Won B is the first verslon that <br />goes into extens.lvo detailprovialons of other nationally known spec1fk:atIom and <br />standards that have a lo~ hlstoty of reUabllliy. Thls hiatoxy ~u1d be of interest to you <br />considering the hundreds Mthouaands (ifnot mUllons) ofsltes throughout the United <br />States which have stnJctUi.'es designed with oODCepts spelled out in publications Uke "The <br />Design of Steel Transmission Pole Structures" (published by A,S,C.E,), and "Standard <br />Specl:flcatlons for Stroctw:al Supports for HJ8hway Sip, Lumlnarlcs and TrafBc Signals" <br />(pu~d by A.A.S.~.T.O.). Many of'the concepts used to' design poles In those two <br />publications are included fn the E.I.A.fI\I.A 222 R.evlsion B Standard. <br /> <br />The E.I.A.ff.I.A. 222 Re-rision E requirCIrWmtS dictate 8 maximum basic cleaJgn wind <br />speed. The wind speed u, be used depends on 1he location of the slte within the &tate. <br />Valmont's palloy is to WK the wind loading in B,I.AIl'loA. 222 as a mf11tmJl1111oDdJng. <br />StatLsticBlly. the wind spe.:d listed in E.I.A.IT l.A. 222 heB been determlned to be that <br />wind which has an averag e reoccu.rnmce of 50 years. ThIs wind is also 8 ''fastest mile" <br />wind whloh means that it .Is the aVeragd veloofty of B mile wind pSB.Smg B point. For <br />example, a 70 mph averal:e fhstest mile wind would take 51 scconda to pallS a point, This <br />lrtaDdatd ''BuItest u" wJ od is customized with factol'S that applY to the partk1uIBi' <br />