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NWTE NorthWest Tower Engineering <br /> Rucker Hill, Everett, WA Report No. 210621.13 April 22, 2021 <br /> Analysis Method <br /> A three-dimensional finite element model of the tower was created using tnxTower Version <br /> 8.0.7.5 (Tower Numerics, 2020). This computer software program calculates and distributes <br /> wind and ice loads in the model. It calculates the resulting forces (required strength) in all <br /> structural members and determines tower deflections and foundation loads. Required strength <br /> of each structural member is compared to each member's design strength determined using the <br /> TIA-222-G standard. <br /> Analysis Results <br /> The following ratios of required strength to design strength for the tower's structural members <br /> were found: <br /> MEMBER STRENGTH RATIO <br /> Elevation Existing Configuration Proposed Configuration <br /> (ft) Member Maximum aLa Capacity Maximum % Capacity <br /> Leg 64 82 <br /> 0 - 300 Diagonal 77 (bolt) 86 (bolt) <br /> Horizontal 40 46 <br /> Guywires 61 69 <br /> The attached tables contain more detailed lists of member forces and capacities. Capacities of <br /> all structural members and guy wires were found to be adequate. <br /> The tower mast rests on a concrete pier that is approximately 5' square. Dimensions of the base <br /> foundation below grade could not be verified. Three guy anchors each are located at radii of 84' <br /> and 170'. Each anchor consists of a steel arm embedded in a buried concrete block. According <br /> to the drawings, the dimensions of the inner anchors are 4'-6" wide x 3' deep x 15' long with 9' <br /> of soil cover. The dimensions of the outer anchors are 3' wide x 3' deep x 15' long with 9' of soil <br /> cover. Site specific soil information was not provided. <br /> Original design reactions were increased by a factor of 1.35 per TIA-222-G, Section 15.5, to <br /> allow a comparison to be made with the factored foundation reactions calculated in this <br /> analysis. The factored original design reactions were found to be significantly greater than the <br /> calculated reactions for this analysis. Based on this comparison, the base foundation and guy <br /> anchors are considered to be adequate. Due to a lack of site specific geotechnical information, <br /> a rigorous analysis of the foundations was not conducted. <br /> Calculations confirmed the adequacy of the bolts in each leg splice and bracing connection. <br /> Welds, plates, and other elements of the connections are assumed to be adequate. <br /> Seismic calculations were performed using the equivalent lateral force procedure in accordance <br /> with ASCE 7-10, Minimum Design Loads for Buildings and Other Structures. Seismic forces <br /> were distributed over the height of the tower in accordance with ASCE 7-10. Resulting values <br /> for shear forces in the tower were then calculated at multiple levels and compared with shear <br /> forces generated from wind loads. Wind load was found to govern over the full height of the <br /> structure. <br /> NorthWest Tower Engineering 4 www.nwtower.net <br /> 3426 Broadway,Suite 302,Everett,WA 98201 Tel 425-258-4248 Fax 425-258-4289 <br />