Aeroelastic Testing of Span-Wire Traffic Signal Systems

• Main Authors: Ziad Azzi, Manuel Matus, Amal Elawady, Ioannis Zisis, Peter Irwin, Arindam Gan Chowdhury
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-07-01
• Series: Frontiers in Built Environment
• Subjects: traffic signals; span-wire; Froude number; aeroelasticity; large-scale; buffeting response
• Online Access: https://www.frontiersin.org/article/10.3389/fbuil.2020.00111/full

Span-wire traffic signals are vulnerable to extreme wind events such as hurricanes and thunderstorms. In past events in the Southeastern Coast of the United States, many failures of span-wire traffic signals were reported. In order to identify their dynamic behavior during extreme wind events and investigate their buffeting response, a large-scale aeroelastic testing was conducted at the NHERI Wall of Wind (WOW) Experimental Facility (EF) at Florida International University (FIU). The WOW is a large-scale open jet wind testing facility, comprised of 12 fans, and capable of simulating winds at speeds up to 70 m/s, corresponding to a Category 5 hurricane. Following the Froude number criterion, a 1:10 aeroelastic model of a span-wire traffic signal system consisting of two 3-section and one 5-section signals was designed and constructed, based on the properties of its full-scale counterpart. In the testing protocol, various wind directions ranging between 0° and 180° were considered at full-scale wind speeds ranging between 21 and 43 m/s. The results of the aeroelastic tests show a similar behavior compared with previous full-scale tests conducted at the WOW. However, an increase in the RMS of accelerations was observed in comparison with those from the full-scale tests. This is attributed to the fact that the aeroelastic model enabled better simulation of low-frequency eddies in the turbulence spectrum compared to the full-scale testing turbulence spectrum.