Wind Recommendations for Transmission Towers

The recommendations concerning design wind loadings for transmission line towers show a wide divergence. When the varying intents of the codes are reviewed, closer agreement is obtained. For normal cable spans, the proper determination of the effective wind on the wires is the critical factor. The recommendations of Proc. Paper 5403, Electrical Transmission Line and Tower Design Guide provide valid loadings for normal conditions. The special conditions which warrant additional review are short spans, tall crossing towers, or winds following heavy icing. Additional testing and experience is required on multiple conductor bundles before any reduction for shielding of the leeward cable is incorporated into design loadings.