The present study was initiated to investigate the possible causes of excessive lamp failure rates on high-mast illumination towers in the state of Minnesota. This type of highway illumination system consists of high masts on which there are either three or four luminaires. The masts are 120 ft high and the luminaires are atached to a ring assembly that can be lowered for lamp replacement. The study consisted of two methods of analysis that were combined for obtaining information on the motion of the towers and the luminaires. The first step was to analyze numerically the complete system by employing a finite element code and to compute the motions of the complete system under typical wind conditions at the site (wind velocities between 5 and 60 mph). The numerical results provided information about lamp accelerations and the frequencies of motion. The second phase of the study consisted of an experimental effort during which one of the ilumination towers was instrumented and motion data were collected for various wind conditions. The final phase of the study included the evaluation of the numerical as well as the experimental data that had been obtained from the preceding steps. This evaluation included the identification of modes of vibration in the frequency domain, filtering of data for assessment of modal effects, and comparisons of experimental and numerical results.
[1]
Theodor Krauthammer,et al.
THE EFFECT OF WIND INDUCED VIBRATIONS ON HIGHWAY LIGHTING BULBS
,
1985
.
[2]
W. J. Hall,et al.
The Commonality of Earthquake and Wind Analysis
,
1980
.
[3]
Emilio Rosenblueth,et al.
Fundamentals of earthquake engineering
,
1971
.
[4]
R. Clough,et al.
Dynamics Of Structures
,
1975
.
[5]
Hayes E. Ross,et al.
Wind Induced Vibration in Light Poles
,
1970
.
[6]
J. Penzien.
Wind Induced Vibration of Cylindrical Structures
,
1957
.
[7]
Emil Simiu,et al.
Wind Effects on Structures: An Introduction to Wind Engineering
,
1980
.
[8]
Peter Sachs,et al.
Wind Forces in Engineering
,
1972
.
[9]
B. J. Vickery,et al.
Drag or Along-Wind Response of Slender Structures
,
1972
.
[10]
H. Saunders,et al.
Finite element procedures in engineering analysis
,
1982
.
[11]
Edmond D.H. Cheng,et al.
Extreme Winds Simulated From Short‐Period Records
,
1985
.
[12]
Kenny C. S Kwok,et al.
Dynamics of a freestanding steel lighting tower
,
1985
.
[13]
A M Badruddin,et al.
SELF-SUPPORTING TOWERS UNDER WIND LOADS
,
1984
.