Pendulum testing as a means of assessing the crash performance of longitudinal barrier with minor damage

Longitudinal barriers such as w-beam guardrails are subjected to a series of full-scale crash tests to determine their impact performance before being considered acceptable for use on the nation’s highways. Once longitudinal barriers are installed along a roadway, however, they often sustain minor damage in various ways. Since barriers are exclusively tested in an undamaged condition, there is very little known regarding the crash performance of barriers that have sustained minor damage. Transportation agencies responsible for deploying and maintaining these barrier systems need a better understanding of damaged barrier performance to make timely and cost-effective barrier maintenance decisions under the constraints of limited resources. This study is believed to be the first evaluation of the crash performance of strong post w-beam barrier that has sustained minor damage. A pendulum impact testing methodology was developed for the evaluation of two-post sections of strong post w-beam barrier. Pendulum tests were then conducted on barrier sections with five types of damage: (1) vertical tear, (2) horizontal tear, (3) splice damage, (4) twisted blockout, and (5) missing blockout. Based on these tests, vertical tears were found to be a significant threat to the structural adequacy of the barrier section with a high likelihood for rail rupture. A missing blockout at the splice location was found to result in marginal performance with one test resulting in a large rail tear at the splice. Mid-span horizontal tears and splice damage, with one of eight bolts lacking bearing capacity, were found to have a less significant threat on the structural adequacy of the barrier. Twisted blockout damage was found to have no effect on the structural crash performance of the strong post w-beam barrier.