Vibration and fatigue life of steel strand

RECENTLY REPORTED failures of steel ground strand attributed to vibration fatigue have stimulated new effort toward probing for possible explanations of the underlying reasons for the outbreak. The study of the construction practices followed by many utilities revealed several facts: failures were more frequently reported on the higher strength grades of strand; final tensions in many cases were set at 25 per cent of rated strand breaking strength at 60 degrees Fahrenheit; experience which was gained many years ago showing the necessity of armoring conductors at the support points has not been applied generally in the case of the ground strand.