Full-scale investigation of wind-induced vibrations of mast-arm traffic signal structures.

Details

• Creators:
  Sinh, Hung Nguyen ; Riedman, Michelle ; Letchford, Christopher ; O'Rourke, Michael
• Corporate Creators:
  Rensselaer Polytechnic Institute. Dept. of Environmental and Civil Engineering
• Corporate Contributors:
  United States. Dept. of Transportation. Research and Innovative Technology Administration ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Traffic signals
  • Vibration
  • Cantilevers
  • Stresses
  • Fatigue (Mechanics)
  • Field tests
  • Vortex shedding
  • Turbulence
  • Wind
  • Sign supports
• Publication/ Report Number:
  C-10-07
• Resource Type:
  Tech Report
• Geographical Coverage:
  New York
• Corporate Publisher:
  New York (State). Dept. of Transportation
• Abstract:
  Because of their inherent ; fl ; exibility and low damping ratios, cantilevered mast ; - ; arm ; tra ; ffi ; c signal structures are suscepti ; b ; le to ; wind ; - ; induced vibrations. ; These vibrations ; cause stru ; ctural stresses and strains to develop in a cyclical fashion which can ; lead ; to reduced service life due to fatigue and, in extreme cases, full collapse. ; In 2001, after the collapse of several of these ; structures throughout the United ; States, American Assoc ; iation of State Highway and Transportation O ; ffi ; cials (AASHTO) ; code standards were updated to include fatigue provisions for tra ; ffi ; c signal supporting ; structures. ; In New York State, there is ; particular concern regarding structures ; spanning longer than 14 me ; ters which currently do not meet these updated fatigue ; provisions. To address this concern, a full ; - ; scale experiment was conducted using an ; existing 25 meter mast ; - ; arm tra ; ffi ; c signal ; structure, located in Malta, NY, in which ; the response of the structure was ; observed in relation to in ; - ; situ wind conditions. ; In previous studies, high ; - ; amplitude vertical vibrations of mast ; - ; arm tra ; ffi ; c signal ; structures have been shown to be due to ; vortex shedding, a phenomenon in ; which alternatingly shed, low ; - ; pressure vortices in ; duce oscillating forces onto the ; mast ; - ; arm causing a cross ; - ; wind response. When the frequency of vortices being shed ; from the mast ; - ; arm corresponds to the ; natural frequency of the structure, a resonant ; condition is created. The resonant condition causes the l ; ong ; - ; lasting, high ; - ; amplitude ; vibrations ; , ; which may lead to the fatigue failure of these structures. ; Turbulence in the approach ; fl ; ow is known to ; a ; ff ; ect the cohesiveness of vortex ; shedding. Results from this full ; - ; scale experiment indicate that the surrounding ; terrain conditions, which a ; ff ; ect the turbulence intensity of the wind, greatly in ; fl ; uence ; the likelihood of occurrence of long ; - ; lasting, high ; - ; amplitude vibrations and also ; impact whether reduced service life due to fatigue is likely to be a concern
  More +
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28330/dot_28330_DS1.pdf
• File Type:
  [PDF - 8.14 MB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
  urn:sha256:1f8d36cf75525efbe119c3a56fa710088974adbb8749606b3ad5b753adcab5d5