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. , • <br /> . /.\ � � • <br /> � <br /> 1200 N. OAK RD. <br /> P.O. BOX t28 <br /> PLYM�UTH� I N DIANA 48563-0128 <br /> S tember 11, 1996 (2�9) 936-4221 <br /> eP Fax �2t s� sss-sTss <br /> Mr. Curtis Rowe <br /> CELLULAR ONE <br /> 2500 Coit Road <br /> Springfield, IL 62707 <br /> Dear Mr. Rowe: <br /> Thank you for your inquiry conceming tawe� design codes and practices. <br /> PiROD has been designing and building guyed, self-supporting tourers and monopoles <br /> since the eariy 1950's. Duri�g this time, we have sold thousands of sirvctures ranging <br /> in height from as iittle as 50' high to in excess of 1400'. These structures were <br /> individuatly engineered io accommodate the ioading requirements impa�ted by the design <br /> windspeed, ice considerations, antenna Ioading,and otherfactors dictated by the national <br /> code requirements existing at the time the tower was built. <br /> The present national tower and monopole code, ANSUEIAJTIA�-222-"E", represents the <br /> latest refinement of spedfic minirnum requirements for engineers and manufacturers to <br /> follow to help assure that the structure and its foundations are designed to meet the most <br /> reatistic conditions for (ocal weather while assunng that the structure is designed to <br /> stringent faciors of safety. <br /> ln the case of the monopole under co�sideration, the owner has elected to exceed the <br /> stipulated oode requirements for windspeed and has also r'equested that 112" ice be <br /> {nduded in the analysis. Ice is considered on all tower members, antennas, and lines <br /> and results in a substantialty heavier tower design than one conside�ed without ice. <br /> The"E"version of the code incorporates an escalating wind factor based on tower height. <br /> "Meetir+g the oode" impties that the design quoted has aN of the code �equirements f�r � <br /> safety factors intact at the windspeed spec.ified. Thus, the ultimate survival speed would <br /> be considerably higher. Again, adding ice to the design foading can also add a further <br /> safety factor to the finai tower strength. <br /> 1Mile failure is extremely rare in any kind of tower, it is especia{ly so for monopo�es and <br /> self-supporting towers. In fact, only if a monopole wece subjected to a direct hit from a <br /> tomado or the severest of hurricanes would failure be predicted. <br />