Design and installation details are given of the tensioned guard rail safety fence developed at the road research laboratory for use both at the side of the road and in the central reserve of dual carriageway roads. The main element of the barrier is made up of lengths of corrugated steel strip 8mm (11 b.g.) thick and 300 mm (1 ft) deep bolted together. It is mounted on knock-down steel posts by means of 8 mm (5/16 in) shear blots so that its horizontal center line is 600 mm (2 ft) above the adjacent carriageway. The ends of the main element are rigidly attached to anchorages embedded below ground in concrete blocks. All slackness between the bolted sections of the main element is taken out during assembly of the barrier, and tensioning devices are fitted into the rear corrugations of the main element at intervals of 70 m (230 ft). the design is the subject of patent no. 1141012.
Abstract