NCHRP Report 718 provides criteria for the fatigue design of high-mast lighting towers (HMLTs). The report also includes a series of proposed revisions with associated commentary to the fatigue design provisions of the AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals. In addition, to ensure the fatigue design provisions are properly implemented into practice, design examples are also provided. The material in this report will be of immediate interest to highway design engineers.
Research was performed under NCHRP Project 10-74 by Dr. Robert Connor, the School of Civil Engineering at Purdue University in West Lafayette, IN. The objectives of NCHRP Project 10-74 were to develop (1) loading and analysis criteria for use in the fatigue design of high-mast lighting towers, (2) a design method and proposed specifications for highmast lighting towers, and (3) design examples. These research objectives were achieved by laboratory testing to investigate the effects of wind gusts (i.e., buffeting), vortex shedding, and associated dynamic oscillations; and a long-term field monitoring study gathered wind and strain gage data from eleven different HMLTs over the course of 2 years. Fourteen additional HMLTs were tested to determine their dynamic properties. Additionally, wind tunnel tests were completed to examine flow separation and wake characteristics of various multi-sided, tapered, tube geometries.