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<br />. <br /> <br />, <br /> <br />" <br /> <br />'. <br /> <br />. <br /> <br />rn <br /> <br />PAUL J. FORD AND COMPANY <br />STRUCTURAL ENGINEERS <br />~so East ElrC:ld 5Irf~( , ~ui(C ~oo . Colum\;JI"i$. Ohio "32 1S <br /> <br />July 16, 1998 <br /> <br />U.S. \"lest Wir~less L.LC. <br />426 Nertn Fairview Ave. Roem 101 <br />St. Paul, MN 55104 <br /> <br />AnN: Mr. DaleT~ 1~I7-q8 <br /> <br />~EO <br />SEP 2." '998 <br />c<<i ~ ~\\ftU",US <br /> <br />. <br /> <br />RE: E:<isling 700 ft. guyed lower <br />Located in ^rd~n Hills, Minneseta <br />(PJF No. T98-028) <br /> <br />. <br /> <br />Dear Mr. Therne, <br /> <br /> <br />(~~~r::~::.~;,:~:k=;~~7:f~:!~;J~:f.:: :~:..;~:=;~.\.~.d E::~~1~e ) <br /> <br />R5-222-Cslandard. Ice accumulatien was tiQI considered inlhe.origini!1 tower d~i8n. . <br /> <br />The purpose of our ana.lysis was to' determine if lne existing strl'cture ceuld meet the requirements ef <br />tne Minneseta Stale Building Code while supperting the revised antenna and ceax loading as shewn <br />on page one ef the enclosed sketches. The Minnesota State Building Cede is medeled aiter the <br />Uniform Building Code,(UBC , 994) and new requires that ice accumulatien be censidered. lhe <br />Minnesota State Building Code dees not list design wind loads for structures ever 400 It tall and <br />recognizes the Electronics Industry Associalio.n standard ^NSllEIA.222-E as an acceptable national <br />design standard. ' <br /> <br />. <br /> <br />Our analysis was performed in accerdance with the recommendatiens ef the ^~SI/H"'-222-E standard. <br />The Minr.eset<l St.lte Building Code requires a minimum design wind velocity ef 80 mph and also. <br /> <br /> <br />r.e.....q.....U........i...r....e...s.........I....."......'.t........a....'.:..'..t..r.u..ct.......u.r...e.....S......i....n..........I.h....e ........s....'.....a.... .I..e.......b......e......d.e..s..'s....n....e.....d............f....a.......r....~....... ....e.f..r...a...?.......'..a....I...i...c.e..........T...h..e....E..I.^...sta......n.......d.....a.r..d.....a.I..I..aw..s..I.h. ..e.. ........~... <br />basic des.gn w.~d velocllyto be decreased to' 69 mph when rad,al.ce accumulallan IS censldered. Th~ <br />(eXistintl t~....'e~haS Jhecap~ily Ie safely withstand,pnly 79m~~ "::ing~.w~nsl:'gp,S~t1&,\h~aolen~-lts.t!1d <br />e'J,pagt_t:<)f~,.lln~lasedskel~~s. :!c;!lJ will nate Ihanhe eX1stiligtower ver)" nearlyt'ill!e'-~~e <br />requirementswnen Ice is not consider~. . <br /> <br />(Whe!! ..~.in,ch ,,~c:li~UCll.l1,CCH~H~tioni~tP/'lsidereclllle lQV{er:has.~bl! C'~"acity to safely '\"'i.thlt~donl>'<) <br />2.5 ~p.lI,~in~".I~~;~~ out 0(the709.~. PfI9,\",.eJ.Jhj! 19"'e.r.le&Sa{~:@f,ffst;~.~l[l,.~M~~!-~J~/ <br />duel()tHll.~~.that .he.lower hagvel'Y sever!ily.bent shape.n Ihe ~!f1~tI'iL.. .... lne guy ables.and all <br />,f.,N",;#~""'.'''''''. ~.","",,~h~ .. _~!,'~ i'~.";.!ji W. .1" ,.",""ho. . <br />tower with larger guy cables at sOme elevations in an attempt Ie control the deflected shape (a stralght- <br />line deflection reduces lower 5hah stresses) of lhe tower shaft. This helped CQr1siderablybut a large , <br />portion of the tower {560 lineal (1) waS sti II severely everstremd. >>'e~e n()lfeellhat.jti~r"asi~t~ 10.). . , <br />(reinforce this tower to. m,eetlhe ie-e leading requirement> of the Minnesota Stal! &r:i1t1tngCcXIe. <br /> <br />. <br /> <br />COLUMBUS, OHIO <br />614-221-6679 <br />/"" 61<.221.2140 <br /> <br />. AT~NTA. GEORGIA . <br />404-266-2407 <br />F.AX A04-Il69--4&O! <br />. www.pjfweb.com · <br /> <br />ORLANDO, fLOP.ID^ <br />407~91,'019 <br />fAX 007~",)"'2 <br /> <br />t <br /> <br />110-11 .....~_tl.P~_.ol.."""".....h""'^'.......... <br />