Ten impact tests were carried out on alternative constructions of cable and chain-link barriers similar to one originally developed in California in 1959 for use on central reservations at least 16 ft. Wide. In this American barrier, a steel cable is clamped on either side of a line of steel posts. It is intended that under impact loading the cables should press into the bodywork of the vehicle to redirect it, their initial height above the ground being maintained at the vehicle by virtue of the fact that they slide off the ends of posts which bend ahead of the vehicle. The tests consisted in guiding cars, usually by remote control, into barriers 200 ft. In length, photographing the vehicle-barrier responses, and measuring vehicle decelerations. Speeds up to 60 mile/h, and angles up to 20 deg. To the line of the barrier were employed. The constructional items common to all but one of the barriers investigated were posts about 45 in. In height, chain-link mesh, and pairs of cables clamped on either side of the posts. The chain-link mesh was dispensed with, and shorter posts were used in the exceptional case. Detailed conclusions are enumerated in the report. The undesirable features exhibited by the barriers tested might be eliminated by reducing the length of the posts which project above the cables, and by providing a readier means of detachment of the cables from the posts. The development of a barrier incorporating these modifications is described in a later report. /RRL/.
Samenvatting