Crashworthiness Testing of a Portable Maintenance Work-Zone Barrier

Barrier and shadow vehicles generally provide Caltrans maintenance workers protection from errant vehicles entering the work zone from the upstream direction of traffic flow. This type of protection does not protect workers from vehicles entering the work zone laterally. In an effort to provide workers with positive lateral protection the portable maintenance work-zone barrie (PMWB) was developed. The PMWB is more commonly known as the Balsi Beam named in honor of a Caltrans maintenance worker who was injured by an errant vehicle while performing his duties.

The Balsi Beam consists of a modified tractor truck and trailer. The trailer has two telescoping box beams, one on each side, that connect the front and back of the trailer. To create a positive workspace, one of the beams rotates onto the other beam to create a double beam barrier. The trailer can then be extended to provide 9.1 m (30 ft) of protected workspace. The beams can both be rotated to protect either side of the trailer so that work can be done on median or shoulder areas. The portable barrier has the ability to be moved forward along the highway without any downtime for disassembly and reassembly. It was developed to be quick, easy, and safe to deploy at the work area.

There are not any specified testing criteria for this type of barrier. Therefore, the barrier was tested under NCHRP Report 350 test Level 2 for Longitudinal Barriers. Two crash tests were conducted, one with an 820-kg small car and one with a 2000-kg pickup truck. The results of the two tests were within the limits of the Report 350 guidelines. There was minor damage to the barrier and sheet metal from the impacting vehicle tended to accumulate at the overlapping joint of the barrier’s box beams.