Washington State Roadway Toll System, WSDOT
WSDOT plans to implement Toll Lanes to provide congestion relief and safety improvements and to develop a Toll System that will create revenue to support future transportation improvements. CivilTech’s role in the Roadway Toll System Project consists of the design of about one hundred hangers to support toll equipment along I-405, SR520, SR99, and for the SR520 Temporary Toll Collection System (TTCS). Our tasks included wind load analysis for the hangers, which was limited to a fundamental frequency that did not exceed 500Hz and vibration that did not exceed 100 inches per second. Hanger connections were also designed for fatigue due to natural wind gusts and truck-induced wind gusts. The hangers will be installed on truss and monotube type gantries and are designed to be field adjustable to accommodate special toll camera and antenna angle requirements. The design incorporates installation requirements that hangers must be crane mounted within a limited time frame, employ positive mounting methods, and maintain 18-feet of minimum vertical clearance between the lowest cross-member and roadway.