Date of Award
Civil and Environmental Engineering
Applied sciences, Communication towers, Guy wire ruptures
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This dissertation discusses several topics relating to the analysis, design, and strengthening of self-supporting and guyed communication towers, some of which are not covered by Canadian Standard CSA S37-01 and American Standard ANSI/TIA/EIA-222-G. The effect of sudden guy rupture and guy slippage on guyed towers, effect of eccentricity on the tensile strength of bolted ring-type splice connections, calculation of prying action on bolted circular splice connections, and strengthening of solid round leg members with split pipes were studied.
Experimental investigation was conducted on small-scale guyed tower test specimens, bolted ring-type and circular splice connections, and solid round steel members strengthened with split pipes. Finite element analysis models of small-scale guyed towers and solid round test specimens were built to simulate the experimental investigation.
Based on experimental investigation, it was found that the maximum load amplification factors due to sudden guy wire rupture with an initial tension of 10% of the guy wire breaking strength ranged from 1.45 to 2.21, and those with doubled initial tension decreased to a range of 1.43 to 1.96. For guy slippage, it was found that those factors ranged from 1.10 to 1.56. The maximum load amplification factors are highest when rupture or slippage happened at top level guy wires. The finite element models can be used to determine the maximum load amplification factors due to sudden guy rupture and guy slippage on tower test specimens.
On the basis of the research, it was concluded that bolted ring-type splices should be designed for combined stresses due to axial tension and bending moment. The equations for prying action given in the Canadian Institute of Steel Construction Handbook and American Institute of Steel Construction Manual can be used in circular flange connections, with the bolt pitch taken as the distance between the centres of bolts measured along the bolt circle.
It is recommended that split pipes be used along the entire solid round steel member and be connected with end welds in addition to U-bolts/tabs. For stocky members, stitch welds are preferable since there is a minimal strength increase by using U-bolts/tabs only. The finite element models can be used to determine the failure loads of un-strengthened and strengthened solid round steel test specimens.
Dostatni, Cindy, "Analysis, design, and strengthening of communication towers" (2011). Electronic Theses and Dissertations. 8119.