This paper presents the results of seven full-scale vehicular crash tests on 35-ft-high breakaway lighting standards with 20-ft-longmast arms and compares them with the recommended crash test criteria in NCHRP report 230 and with the new 1985 AASHTO specifications for structural supports. The test devices consisted of an aluminium lighting standard with cast aluminium breakaway couplings, a lightweight steel lighting standard with cast aluminium breakaway couplings and a triangular slip base, and a typical california department of transportation (Caltrans) type 31 lighting standard with a triangular slip base. The lighting standards tested met the requirements of NCHRP report 230 with minor exceptions. The 1985 AASHTO specifications for breakaway bases, however, were met in all seven crash tests. Although the die-cast aluminium coupling proved to be an effective breakaway device when impacted by 1,800-lb cars, excessive porosity and lack of compliance with Caltrans specifications preclude the use of these couplings as a standard Caltrans breakaway device. The Caltrans triangular steel slip base proved to be an effective breakaway device when impacted by 1,800-lb cars.
Samenvatting