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HomeMy WebLinkAbout3300 S. COLLEGE (PERKINS) WIRELESS MONOPOLE - PDP/FDP - 30-00 - SUBMITTAL DOCUMENTS - ROUND 1 - WTE / WTF INFORMATIONObviously, as with any product, a products quality is dependent upon the processes employed and people who design and fabricate the structure. In order to ensure high quality, we will only employ welders who are certified and have complied with requirements of AWS D1.1. In order to maintain quality we employ a weld inspector fluent in the requirements of AWS D1.1 to inspect and train our personnel. Similarly, only after our engineering staff has gained sufficient experience over many years of training, are design decisions delegated. As Vice President of Engineering, I oversee all engineering and applications of towers and pole structures produced by our firm. I am registered in 41 states including the District of Columbia and I have been employed by PiRod since 1985. 1 am assisted by Mr. Bill Rettig, Chief Engineer, who is a registered engineer in 42 states and has been employed by PiRod since 1990. Bill and I are assisted by six graduate engineers who employ sophisticated modeling techniques to ensure the performance of the structures we fabricate. Much of this experience has been gained by working with Mr. Myron Noble, also a graduate engineer, who founded PiRod Inc. in the 1973. Finally, I must mention that the pole foundations are required by the EIA standard, and similarly, by the National Building Codes, to support the design loadings with a higher factor of safety than the factors of safety applied to the pole.. The foundation design often ,utilizes site specific soil information as determined by a Geotechnical Engineer. Thus, the foundations are considered to be stronger than the pole and are not predicted to fail before the pole itself. By design the pole is not predicted to fall like a tree as a result of any difficulties within the foundation or as a result of the foundation design if the design is completed in accordance with the EIA standard and good engineering practices. We take great strides to ensure that the foundations are designed properly by competent individuals. I hope the above discussion is informative. If any other questions should arise, please feel free to contact me at the above mentioned number, extension #5221. Sincerely, John R.Erichsen Vice President of Engineering Ext. #5221 PiROD inc. P.O. BOX 128 PLYMOUTH, INDIANA 46563-0128 (219) 936-4221 � /AiffijP*RflH 'He* August 22, 2000 Mr. Jim Temple VoiceStream Wireless 2323 Delgany St. Denver, CO 80216 1545 PIDCO DRIVE P.O. BOX 128 PLYMOUTH, INDIANA 46563-012C (219) 936-4221 SALES FAX (219) 936-6796 ENG. FAX (219) 935-4873 ACCOUNTING FAX: (219) 936-456 PURCHASING FAX: (219) 936-035 Re: TP49 x 50' Tapered Monopole Fort Collins, Colorado (Site Name: Perkins Restaurant DN3083D) Dear Jim: Thank you for your inquiry concerning tower design codes and practices as they relate to your proposed tapered monopole for the Perkins Restaurant site in Fort Collins, Colorado. As requested, we have designed a monopole to support the specified antenna loading in accordance with the EIA standard, revision F, at 85 mph with and without 1/2" radial ice. It should be noted this design criteria is not the failure windspeed. It is the design windspeed and thus, the pole would be predicted to fail at a higher windspeed. The design criteria listed above is also very conservative as it is prescribed to be by the EIA standard. Only in an event in which the pole would come into contact with an extreme windload more often associated with hurricane winds or direct contact with a tornado would the pole be predicted to fail. It is also important to remember that failure does not imply that a portion of the pole will be disconnected and will sail through the air. The type of failure predicted is typically a buckling of the monopole shell on the leeward side resulting in a compression failure of the pipe wall. This means that the pole will be bent and not broken. It is also important to note that as the pole bends, it is our opinion, that the load induced will be reduced as the pole presents less of itself to the wind relieving the wind load, and therefore, the pole will have a higher resilience to survive the loads induced by the wind should they persist. This particular tapered -monopole for the Perkins Restaurant in Fort Collins, Colorado, has been designed with weakest point at approximately 25' above grade, which is where failure is most likely to occur. With all of this said, the design standards and practices have added to the conservative nature of the design process by including only the minimum strengths associated with the materials used in fabricating the pole. For instance, it is not unusual for the actual steel strengths exhibited in the final product shipped to the site to be higher than the design minimums used in our computer models. Thus, the scenario painted above is a worst case wind load condition. It represents the minimum capacities that the pole will be required to exhibit.