The results of five full-scale vehicle impact tests on the california type 20 bridge rail are reported. The type 20 bridge rail is a rigid barrier system that incorporates a 27-in. High reinforced concrete parapet with a traffic-side contour very similar to that used for the new jersey type of concrete median barrier. A 2- by 6-in. By 1/4-in. Thick structural steel tube rail is placed 12 in. Above the top of this parapet, thus giving an overall barrier height of 39 in. Five tests were conducted at speeds of from 45 to 66 mph and at impact angles of 7, 15, and 25 deg. The test results indicated that this system will retain and redirect a 4,900-lb passenger vehicle impacting at speeds up to 65 mph and at angles of from 7 to 25 deg with the barrier. Vehicle damage varied from negligible at a 7-deg impact angle to severe at a 25-deg impact angle. The test results indicated that the vehicular decelerations sustained during 25-deg, 65-mph impacts into this system will result in occupant injuries varying from severe, if no restraints are used, to no more than moderate, if both a seat belt and a single diagonal shoulder harness are used. At impact angles of 7 deg and less, little or no injury will be substained regardless of the restraint system used. (Author/publisher)
Abstract