Effect of Galvanization on the Fatigue Strength of High Mast Illumination Poles

This research investigation studied the effects of galvanization on the fatigue life of high mast illumination poles. Reports that galvanization of high masts caused initial cracks to form at the toe of the weld connecting the base plate to the shaft of the pole were first validated. The effects of these initial cracks on fatigue strength were then checked through experimental testing.

A variety of variables were tested for both their effects on the occurrences of the initial cracks and effects on fatigue life. These variables included testing galvanized against ungalvanized specimens, testing of varying fabricators and galvanizers, and testing of various types of connection details. These test results were compared against inspection results provided by Texas Department of Transportation inspectors.

Also, methods of mitigating the effects of toe cracks on the fatigue life of poles were investigated. A method for repairing specimens both in the fabrication shop and in the field were developed and tested. Both methods showed strong improvement in fatigue life of the specimens providing a possible repair solution.