National Center for Wood Transportation Structures

About the research

Traffic signal structures are an integral part of the transportation infrastructure system, ensuring the safety of motorists and pedestrians. These structures, however, have been found to perform poorly due to fatigue-related issues in their connections. This mostly originates from the large-amplitude vibrations caused under galloping, vortex shedding, and natural wind and truck-induced gusts. The inherent dynamic properties of these structures, especially their low mechanical damping (0.1%-0.4%), is proven to be a key contributing factor, further exacerbating the fatigue-related issues. While most of investigations performed to date have been focused on the development of vibration mitigation strategies or the design of fatigue-rated connections, much less attention has been given to a more fundamental solution, stemming from the modification of the aerodynamic characteristics of this category of structures, addressing the issues at their roots.Considering the large number of traffic signal structures used for traffic control, their cost of repair and reinstallation can add up fast, while their potential failure can pose an immediate risk to the traveling public. This has led to a growing need to develop more cost-effective solutions to mitigate the large-amplitude vibrations of both new and existing traffic signal structures.