FATIGUE ANALYSIS OF THE CAST ALUMINUM BASE

CAST ALUMINUM TRANSFORMER BASES AND CAST ALUMINUM SHEAR BASES HAVE HELPED REDUCE THE HAZARD THAT ROADWAY LIGHTING PRESENTS TO THE MOTORIST. THIS SAFETY FEATURE RESULTS FROM INHERENT BREAKAWAY CHARACTERISTICS OF THESE TWO BASES. VIBRATION DUE TO THE AERODYNAMIC CHARACTERISTICS OF THE POLE WERE INVESTIGATED TOGETHER WITH THEIR EFFECTS ON THE FATIGUE LIFE OF A CAST ALUMINUM TRANSFORMER BASE AND A CAST ALUMINUM SHEAR BASE. STUDY OBJECTIVES WERE TO:(1) DEVELOP A COMPUTER PROGRAM, FROM A MATHEMATICAL MODEL, TO BE USED IN DETERMINING THE DYNAMIC RESPONSE OF LIGHT POLES SUBJECTED TO STEADY WINDS, (2) DETERMINE THE DYNAMIC RESPONSE OF TWO TYPICAL LIGHT POLES WITH TYPICAL LUMINAIRES ATTACHED FOR WIND VELOCITIES BETWEEN 0 AND 50 MILES PER HOUR, AND (3) FROM THE RESPONSE DETERMINE IF A FATIGUE FAILURE WILL OCCUR IN THE CAST ALUMINUM TRANSFORMER BASE OR THE CAST ALUMINUM SHEAR BASE. BASED ON THE RESULTS OF THIS INVESTIGATION IT APPEARS THAT VIBRATIONS IN LIGHT POLE STANDARDS, DUE TO THE VON KARMAN VORTEX STREET, WILL NOT RESULT IN A FATIGUE FAILURE OF THE CAST ALUMINUM BASE. THE MINIMUM FACTOR OF SAFETY OF 5.40 FOUND FOR THE TWO POLE CONFIGUATIONS CONSIDERED FORMS A BASIS FOR THIS CONCLUSION. IT WAS DEMONSTRATED THAT THE MATHEMATICAL MODEL OF THE LUMINAIRE SUPPORT STRUCTURE CAN BE USED TO DETERMINE THE DYNAMIC RESPONSE OF LIGHT POLES UNDER WIND LOADING.

  • Supplemental Notes:
    • Res Rept 75.11, 10 FIG, 5 TAB, 8 REF
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 1600 E Lamar Boulevard
    Arlington, TX  United States  76011
  • Authors:
    • Ross, H E
    • Edwards, T C
    • Babb, G R
  • Publication Date: 1968-8

Subject/Index Terms

Filing Info

  • Accession Number: 00203415
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 2 1994 12:00AM