Who needs the highway, the quarantine rail, the fence, the traffic barrier, the continental barrier, the prison separation gate and the airport?
Several problems should be paid attention to when installing guardrail network in highwayWhat problems should we pay attention to when installing the guardrail network in the freeway? First of all, we need to know: the application of construction in the city is very extensive, but the installation height of fence is also a problem related to the use of safety; column fence height determines the basic installation height of isolation facilities, this index is an important parameter in the design of the fence, the value of height directly influence the cost and effect. The main consideration of the height of guardrail is the density of people and the terrain along it.
Because the fence column height is lowered, it is recommended that the column spacing be 4m, which is set at 5m, then 201 per kilometre; if 4 meters are set, 251 columns per kilometre, that is, 50 columns per kilometre. Mesh and wire in the rural village near people around the network activity, should adopt the metal mesh or steel net. Therefore, type nets are not harmful to humans. The design shall be made of lower density (0~60cm high), 10 * 15cm hole and sparse (60~120cm high) isolating net, 20 * 30cm hole, so as to save material and save cost. But because the cost of the steel mesh is higher than that of the metal mesh, and the aesthetics is slightly worse, and the adaptability to the complex terrain is relatively weak, the high-speed road on the domestic construction has been rarely adopted at present. A metal mesh mesh, welded mesh fence, pull three, is more commonly used in welding net. There are two types of welded nets: roll net and mesh net. Because the roll net is simple to install, the whole strength is high, and the adaptability to the complex terrain is strong (the mesh can be cut arbitrarily), the roll screen should be recommended in the general design. In the mountainous areas, forest areas, pastoral areas and other sparsely populated areas, barbed wire is cheaper due to barbed wire type.
With the development of society and the improvement of people's legal consciousness, the number of people who violate traffic laws is bound to decline. Britain and other developed countries highway double ring fence design height is about 1.3 meters. Therefore, the fence should not be set too high, it is recommended in the general area, fence exposed height in the 1.2m-1.5m can be, the special areas in 1.6m is appropriate. This height of people is not easy to cross, but also saves investment.
6 specifications for the use of cold-formed equilateral channel steel are provided for different force conditions, while other appropriate cross section steel is also available under the condition of strength and stability. From the main force direction of the channel column, the choice of specifications should make the core of the Y-Y axis (Iy) larger channel steel. The effective height of the national JTJ074-94 fence standard ranges from 1.6~1.8m, and this range of values takes into account the adult height to prevent crossing as the main design goal. It is observed that if people want to enter the highway, they usually destroy the guardrail, and the damage position is below 1.2m. Set up a high fence, although it can better prevent people from crossing, but it can not prevent people from entering the highway. What can really regulate people's behavior is legal awareness and social civilization.
