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J u.ti �� �1 1..-iii i it :. d iD MILL - ND P. 1 <br /> •TUN P5 '57 e2: i 4PM <br /> • <br /> T KM .r• <br /> fl � t, * J^�r -sr �*. ra <br /> f.+4w ai . u.ril• 11• l <br /> : : ?; <br /> ? June 5, 1997 <br /> Fki• <br /> . <br /> �y <br /> Scott Ballance <br /> Bechtel <br /> ' US <br /> 's;�. West Wireless Project <br /> 426 North Fairview, Room 101 <br /> St. Paul,MN 55104 <br /> ; RE: Miflerb toad Mfg. Co. Antenna Monopole Structural Integrity <br /> The Millerbemd Mfg. Co. monopoles used by US West for this project meets or exceeds the <br /> • <br /> requirements of EIAJTIA 222 "Structural Standards for Steel Antenna Towers and Antenna <br /> Supporting Structures" specification. This is the recognized specification for these types of <br /> ;,,x: towers. When designing the structure, wind &ice loading along with the number, size, height <br /> •s and style of mounting of the antennas are taken into account to determine the size of the <br /> ' structure required. The structure will have an approximate safety factor of 1.5, or in other <br /> ==� ': words,will be 1.5 times stronger 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 /> == Millerbemd Mfg. Co. only uses American-Made carbon steel(ASTM A572 or A607)which has <br /> 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 welrlin <br /> • <br /> of the structure. Weld inspections will be performed by SNT-TC-1A qualified Non-Destructve <br /> } Test Personnel to verify the soundness of the welds. <br /> With the pole designed and manufactured in accordance with the above criteria, Millerb=ad <br /> Mfg. Co. certifies that the monopole will not collapse. If for some reason, the Win r1 loariing <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 I. The b=diag will <br /> cont4mte until the antennas at the top of the pole reach a position such that the wind is blow <br /> over the antennas and not into them. Once this position is reached, the monopole will stc <br /> bending and maintain that position. For the bending to happen, the wind would have to re ch <br /> over 175 MPH and be maintained for a lenzth of time. <br /> x4": <br /> fes= <br /> y.s . <br /> t r - <br /> MILLERBERND MANUFACTURING COMPANY• PO. BOX 98 • WINS i ED, MINNESOTA 55395 <br /> PHONE(320) 485-2111 • FAX(320) 485-4420 <br />