Aesthetically Pleasing Steel Pipe Bridge Rail-Texas Type T421

摘要

Research has developed railings to withstand impact loads from vehicles of ever-increasing size; however aesthetic considerations have been overshadowed by safety and structural requirements. The objective of the research study was to develop aesthetically pleasing, structurally sound railings that can serve as alternative railings in city or urban areas. The report presents a new steel pipe bridge rail--Texas Type T421. The bridge rail is constructed of 5-in.-diameter steel pipe posts with a 5-in.-diameter steel pipe top rail 32 in. high and a 10-in.-diameter steel pipe lower rail. The bridge rail was crash-tested and evaluated in accordance with NCHRP Report 230 for Service Level 2. Two crash tests were required--a 4,500 lb passenger car at 60 mph and 25 degree impact angle and an 1,800 lb passenger car at 60 mph and 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/compartment impact velocities and 10-ms occupant ridedown accelerations were within the limits recommended in NCHRP Report 230. The vehicle trajectory at loss of contact indicates no intrusion into adjacent traffic lanes.