Increased Damping in Cantilevered Traffic Signal Structures

Abstract

Dynamic characteristics of a traffic signal structure were determined experimentally. Various strategies were investigated to provide additional damping. By decreasing the magnitude and the number of fatigue cycles caused by wind-induced oscillations, the service life is expected to be extended. Several damping devices were investigated and tested. The free-vibration response was used to determine the in- and out-of-plane damping of a full-scale pole with and without dampers. The dampers included elastomeric pads located within the joints, several impact dampers, tuning-mass systems, and a mechanical shock absorber (with a strut) positioned between the luminaire extension and the mast arm. An elastomeric pad located at the pole foundation connection and the shock absorber exhibited the most damping and were considered viable and practical options. The construction characteristics of each damper were noted.