In recent years, the bridge has been applied in some projects, with the advantages of beauty, light weight and convenient installation. Do you know what the corresponding system composition of Shandong cable bridge design is?
The cable tray is divided into trough type, tray type and ladder type structures, which are composed of brackets, brackets and installation accessories. (as shown in Fig. 1), during type selection, attention shall be paid to whether all parts of the bridge meet the requirements of serialization, generalization and standardization.
The bridge in the building can be assumed independently or attached to various buildings (structures) and pipe gallery supports. It should reflect the characteristics of simple structure, beautiful appearance, flexible configuration and convenient maintenance. All parts should be galvanized. If the bridge is installed outside the building in the open air, if it is near the sea or belongs to the corrosion area, the material must have the physical characteristics of anti-corrosion, moisture resistance, good adhesion and high impact strength.
Load of bridge
The load of cable tray is divided into load, dynamic load and additional load.
Static load refers to the type and number of cables laid in the cable tray, and the outer diameter weight / unit length of each cable. It is listed and counted according to different routes of cable laying.
Dynamic load refers to the weight of construction and maintenance personnel during the installation and maintenance of cable tray. For light cable tray, dynamic load is generally not considered, that is, people are not allowed to stand (walk) on the tray. If people need to be considered, the span should be appropriately reduced. The additional load only refers to the load formed by ice, snow, wind and electromagnetic force. It is related to the natural meteorological conditions of the installation site and the nature of the charged body. It shall be calculated according to various conditions in the design.
To select a bridge
(1) Determine the bridge width, number of layers, type and spacing of support points, and distribution of cables on each layer of bridge.
(2) Calculate the uniformly distributed load (KN / m2) of each layer of cable, and preliminarily determine the model and specification of the bridge.
(3) The bridge strength shall be checked and calculated according to the large total uniformly distributed load value of the cable. The checking formula is as follows:
Q use = Q1 + Q2
Where: Q1 - uniformly distributed load of the cable (the greater of the uniformly distributed loads of each layer) (KN)/
M2), uniformly distributed load is the load of tray, ladder or cable tray;
Q2 - uniform load (KN /) equivalent to the weight of people during cable laying or maintenance
M2), Q2 value, and the weight of a person is generally calculated as P = 90kg.
Represents the bending distance of concentrated load and uniformly distributed load, as shown in Figure 2
Converted according to the condition of equal large bending distance:
Let p ι/ 4=ｑ2 ι 2 / 8, then Q2 = 2P/ ι
Where: P -- load of 1 person (kg)
ι－- Spacing of one support point (if the spacing of support points is not equal, the larger value shall be taken) (m)
Q2 - equivalent uniformly distributed load of 1 person (kg / M)
According to the above preliminarily determined bridge model, specification and fulcrum spacing, refer to the manufacturer's sample data, and repeatedly check the spacing and bridge model until the load requirements are met. For more information, please visit our website http://www.yeeones.com Consult and understand.