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• <br /> _ JUN 05 '97 01:13PM MILLERBERND . �.. ...:.•.. .��. :.•:..:.. <br /> -MILLERBERND Jules , 102:14p,i <br /> .1-:e.1774:: ••-•--- . . ,.• :i :: <br /> .:,7:-!-'7:...:1-::.F..777.77:7;::::•:. • • <br /> A <br /> • ' <br /> i. <br /> I June 5, 1997 <br /> : <br /> . <br /> Scott Ballance <br /> : !,,F. Bechtel . <br /> :• US West Wireless Project <br /> 426 North Fairview,Room 101 <br /> St. Paul,MN 55104 <br /> Y.: <br /> RE Millerbetnd Mfg. Co.Antenna Monopole Structural Integrity <br /> . <br /> The Millerbemd Mfg. Co.monopoles used by US West for this project meets or exceeds the <br /> = requirements of EIA/TIA 222"Structural Standards for Steel Antenna Towers and Antenna <br /> L ' Supporting Structures" specification. This is the recognized specification for these types of <br /> towers. When designing the structure,wind&ice loading along with the number, size,height <br /> •:t. <br /> and 'le of mountingofthe antennas are taken into account to determine the size of the <br /> : structure required. The structure will have an approximate safety actor of 1.5, or in other <br /> will be 1.5 times stronger op sign <br /> ,,-� words, than it needs to be. The monopole has been designed to <br /> .:= withstand at least 100 MPH with a 1/2"thick coating of ice on the monopole and antennas. <br /> ••'' Mllerbemd Mfg. Co. only uses American-Made carbon steel(ASTM A572 or A607)which has <br /> _- .a a 50,000 PSI min yield. All our steel is ordered with mill certifications to verify integrity of the <br /> material The mill certifications are kept on file, should a copy be required at some future date. <br /> ' Only AWS-D1.1 "Structural Welding Code"qualified personnel will be used during the welding_ <br /> of the structure. Weld inspections will be performed by SNT-TC-1A qualified Non-Destructive <br /> Test Personnel to verify the soundness of the welds. <br /> With the pole designed and manufactured in accordance with the above criteria, Millerbernd <br /> Mfg. Co. certifies that the monopole will not collapse. If for some reason,the wind loading <br /> exceeds the monopole carry capabilities,the pole will not collapse,but rather the top of the pole <br /> will start to bend over and the pole will begin to look like an upside down J The bending will <br /> rj is : continue until the antennas at the top of the pole reach a position such that the wind is blowing <br /> , over the antennas and not into them. Once this position is reached, the monopole will stop <br /> :: :: bending and maintain that position. For the bending to happen,the wind would have to reach <br /> over 175 MPH and be maintained for a length of time. <br /> . <br /> f i;: <br /> .. <br /> • •1 <br /> 1. <br /> MILLERBERND MANUFACTURING COMPANY• P.O. BOX 98 • WINSTED, MINNESOTA 65395 <br /> PHONE(320)485-2111 • FAX(320) 485-4420 <br />