Research has developed railing to withstand impact loads from vehicles of ever-increasing size; however, aesthetic considerations have been overshadowed by safety and structural requirements. The objective of this research study was to develop aesthetically pleasing, structurally sound railings that can serve as alternative railings in urban areas. A new type of open concrete bridge rail--texas type t411--is presented. This bridge rail is constructed of reinforced concrete 32 in. High by 12 in. Thick and contains 8-in.-Wide by 18-in.-High openings at18-in. Center-to-center longitudinal spacing. The bridge rail was crash-tested and evaluated in accordance with nchrp report 230 for service level 2. Two crashtests were required--a 4, 500-lb passenger car striking at 60 mph and a 25-degree impact angle and an 1, 800-lb passenger car striking at 60 mph and a 20-degree impact angle. In both tests the bridge rail contained and redirected the test vehicle. There were no detached elements or debris to present undue hazard to other traffic. The vehicle remained upright and relatively stable during the collision. The occupant impact velocities and 10-msec occupant ridedown accelerations were within the limits specified in nchrp report 230. The vehicle trajectory at loss of contact indicates no intrusion into adjacent traffic lanes (exit angles of 0 degree and 5.9 Degrees). These test data also met the occupancy safety evaluation guidelines in the 1989 aashto guide specifications for bridge railings. This paper appears in transportation research record no. 1258, Roadside safety 1990.
Samenvatting