DEVELOPMENT AND TEST OF FIBERGLASS LOW-IMPACT RESISTANT TOWERS

A break-away fiberglass mast for use in low impact resistant (LIR) structures to support airport approach lighting systems has been developed. This design will withstand 100 mph winds (including gusts) without ice and 75 mph winds (including gusts) with a 1/2 inch radial ice load. Yet, when struck by a light airplane wing, it breaks into pieces without catastrophic damage to the wing. It was observed that impact energy needed to break the mast was in the order of 679 foot-pounds and that peak forces were in the order of 5,656 lbs. (Author)