| 摘要 |
<p>Bollards are extruded in polyethylene in hollow triangular or circular section and set in the ground in concrete. A bulge formed by one means or another in the extruded length gives a good anchorage. The walls of the extrusion are very thin, so that the bollard will bend under the impact of a vehicle, and do it no damage. The polyethylene of the bollard is an unsuitable material to take the reflecting indicator, which is therefore put on a cap or cuff of polystyrene, ABS or polyester and set on the bollard. The area immediately surrounding the indicator is black, the main length of the bollard, white.</p> |
