impact tests with a car and a passenger coach were carried out on a bridge parapet designed by messrs. christiani and nielsen limited. the novel feature of the parapet is the design of the posts which pivot about their bases against the resistance of built-in hydraulic shock absorber units the parapet is intended as an alternative to group p1 vehicle parapets specified in ministry of transport technical memorandum (bridges) no.be5, which are required to contain a car weighing 1.5 mg striking at 113km/h and 20 degrees; there are no current requirements in respect of heavier vehicles. the test car weighed 1490 kg and struck the parapet at 99 km/h and 19degrees. it was redirected in a curved path first away from and then back towards the parapet in the desired manner. the passenger coach weighed 5.4 mg and struck the parapet at 89 km/h and 19 degrees. it was contained by the parapet and redirected at an angle of 9 degrees without overturning, although it exhibited appreciable roll towards the parapet. in these tests the containment and redirection properties of the hydraulic parapet were satisfactory for the car and were better than those of current group p1 parapets for the heavier vehicle. (a)

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