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SS <br />T <br />STRUCTURAL SYSTEMS TECHNOLOGY, INC. <br />P.O. BOX 876 6867 ELM STREET <br />McIEAN, VA. 22101 PH. (703) 356.9765 <br />FAX # (703) 448-0979 <br />May •22, 1989 <br />Indian River County, Florida <br />County Commissioner Office <br />Re: Affidavit on Mode of Guyed Tower Collapse <br />Gentlemen: <br />This is to certify that guyed towers ranging from 100 to 2000 <br />feet in height collapse in a folding mode within an area with a <br />radius, from the tower base, of 0.40 x Tower Height, i.e., a <br />2000 foot height guyed tower shall collapse within a radius not <br />exceeding 700 feet from the base of the tower. <br />Accordingly, a .500 foot height guyed tower shall collapse within <br />an area with radius not exceeding 200 feet from the base of the <br />tower, which is somewhat less than the 260 ft. distance to the <br />closest property line. <br />The following constitute the basis for the development of the <br />above rules: <br />1. Theoretical analysis. <br />2. Tests on 1:20 scale Guyed Tower Models. <br />In the WPGC-FM Prince George's County, Maryland zoning case <br />we executed a 1:20 scale model test for the proposed 500 ft. <br />Guyed Tower and the special exception was .granted. <br />3. Historical data from actual Guyed Tower Failures. <br />In. the past twenty-five years we have observed a few Guyed <br />Tower Failures and in all cases the radius of collapse was <br />within 35% of the Tower Height. <br />It is our professional opinion that Guyed Towers properly <br />designed, fabricated, erected and maintained constitute <br />exceptionally safe structures. <br />MJV/bas Mthew J. Vlissides, P.E. <br />pecial Consultant <br />cc: Molly Beard <br />Jack Mullaney <br />ATTACHMENT 6218 <br />