Wind Load Effects on Signs, Luminaires and Traffic Signal Structures

摘要

The objectives of this study were: (1) to revise the wind load section of theTexas Department of Transportation (TxDOT) standard for highway signs, luminaires and traffic signal structures, and (2) to develop strategies to mitigate large vibrations in single-mast traffic signal structures subject to cross-wind vibrations. The first objective was accomplished by developing a new design wind speed map for the State of Texas. State-of-knowledge wind engineering technology is incorporated in the revised design standard. A better understanding of the cross-wind vibration problem, which takes place in steady winds in the range of 5 to 15 m/s, was obtained by conducting water table, tow tank and field studies. The vibrations are attributed to a galloping phenomenon, which primarily takes place when the wind is blowing normal to the mast arm from the back side of a traffic signal with backing plate. The most effective mitigation measure was found to be a horizontal wing attached above the signal light. TxDOT maintenance personnel shoud install wing when mast arm tip vibrations exceed 40 cm.