The bridge is a support for supporting and placing cables, which is widely used in engineering. As long as cables are laid, the bridge is used. The bridge is divided into trough type bridge, tray type bridge, ladder type bridge, grid bridge and other structures; It is composed of bracket, bracket and installation accessories. Then, if you want to use it, you need to know the knowledge points of the bridge. Let's talk about them below.
1. The fire rating of the cable tray is selected. The part with fire protection requirements can be added to the cable ladder. The fire-retardant performance of the fire or plate used for the tray, such as the network, forms a closed or semi closed structure, and the fire-resistant coating is applied on the steam water bridge and its surface. The overall performance of the fire-resistant material shall meet the requirements of relevant national codes or standards.
Aluminum alloy cable bridge is not suitable for high fire protection. Under the same specifications, the cost of flame-retardant cable bridge is 2.2 times higher than that of steel cable bridge, the service life is more than 5 times that of steel cable bridge, and the weight is 30% heavier than that of steel cable bridge. The fire-proof cable bridge is slightly more expensive than the steel cable bridge, and its service life is more than three times that of the steel cable bridge. The weight is basically the same as that of the cable bridge.
2. Selection of filling rate of Shandong cable tray: the width and height of cable ladder and tray shall meet the requirements of filling rate. In general, the filling rate of cable ladder and tray shall be 40% ~ 50% of power cable and 50% ~ 70% of control cable, and 10% ~ 25% shall be reserved for project development allowance
3. The load level of cable tray shall be selected according to the load level of the cable tray. The uniformly distributed working load of the cable tray shall not be greater than the uniformly distributed level of the rated load of the selected cable tray. If the supports and hangers of the actual span cable tray are not equal to 2m, the uniformly distributed load shall meet the requirements. The specification and size of each component and support frame shall match the straight part and curve of the tray and ladder.
4. Specification and size selection of Shandong cable tray in engineering practice, the problem of specification and size selection of cable tray is either too large or too tight. Relevant regulations: "the ratio of the total cross-sectional area of the cable to the cross-sectional area in the tray shall not be greater than 40% for power cables and 50% for control cables".
That's what you need to know about the bridge. If you have anything you don't know about this, please come to our website http://www.sddlqj.cn Consult and understand.