Scope of Nanjing Bridge Frame Application: Cable bridge frame for indoor and outdoor, high and low voltage transmission and distribution projects in industrial and civil buildings.
1. Normal use conditions
1) The altitude of the installation site does not exceed 2000 meters.
2) Different climate environments use different climate environment grade parameters, selected according to temperature, humidity, fire prevention and other conditions.
2. Special conditions of use
1) Lay in different chemically corrosive environments: salt spray, hydrogen sulfide, hydrogen chloride, etc.
2) Lay in fire protection lines.
3) Lay above 2000 meters above sea level.
3． Structural requirements for cable trays
1) Protection level: non-perforated tray (groove) indoors not lower than IP30 outdoor not lower than IP33
2) Protection level: Fire-resistant bridges are not less than IP40 indoors and not less than IP44 outdoors
Materials should meet their own relevant standards
Steel should be cold rolled steel plate GB / T700-1988 GB / T11253
Aluminum GB / T3880 and GB / 6892
FRP GB / T15568
Refractory bridge GB8624-1997 Class B
3) Common specifications
Height 40 50 60 80 100 150 200
Width 60 80 100 150 200 250 300 400 500 600 800 1000 1200
4) Sheet thickness
Steel bridges allow minimum plate thickness:
Width B allows minimum board thickness &
B1 <00 1.0
100≤B ＜ 150 1.2
150≤B ＜ 400 1.5
800 ＜ B ＜ 1000 2.5
1000 ＜ B ＜ 1200 3.0
The thickness of the connecting piece is at least selected according to the same plate thickness of the bridge frame, and a grade can be selected.
The thickness of the cover plate can be selected one level lower according to the thickness of the bridge.
5) Straight-through length: L = 2000 L = 3000 L = 4000 L = 6000 L = 8000
Fourth, bridge inspection
1. Inspection of bridges according to corporate standards
2. Inspection procedures and testing methods
1) Appearance: The plating and coating surface of the bridge should meet the requirements of Table 2, test methods, and visual inspection methods.
2) Appearance: Two pairs of sides should be parallel, two sides should be perpendicular to the bottom, and the shape of the section should be straight, without defects such as bending, twisting, cracking, edge burrs, etc.
3) Slots should be smooth, flat, and without damage to cable insulation, protrusions and sharp angles.
3． Surface treatment
The surface of Nanjing bridge frame should be plated and coated according to the requirements of the working environment. The thickness and adhesion of various protective layers should meet the requirements of Table 3.
1) Thickness The thickness of the hot-dip galvanized bridge main body is 1.5 ~ 3mm, the minimum average thickness is ≥55am, the minimum local thickness is 45am, and the minimum local thickness is 45am.
Detection standard: GB / T13912-92
Detection method: use magnetic thickness gauge to detect.
2) Galvanized or zinc-nickel alloy
Main body of bridge ≥12 am Note (93)
3) Spray or paint
The detection method of the main body of the bridge ≥50 am is according to GB1764 magnetic thickness gauge
4) Adhesion—the adhesion of the coating to the substrate
Hot-dip galvanized shall not fall off according to the test in Appendix B
5) Galvanized and zinc alloy
Test according to Appendix B shall not fall off
6) Spraying or painting
Not less than Class 3 in GB1720, adhesion tester for inspection.
The surface gloss of the protective treatment shall not be less than 60%.
Detection method: According to GB1743, oil film gloss measurement method, digital display with gloss meter to display directly.
5. Salt spray resistance
The surface protective layer shall have level 3 salt spray resistance as specified in Table 4.
6. Manufacturing accuracy
1) The limit deviation of the length of the bridge
When the length is less than or equal to 2 meters, the limit deviation is ± 2mm, and when the length is greater than 2mm, the limit deviation is ± 4mm
2) Limit deviation of bridge width
When the width is greater than 400mm, the limit deviation is ± 4mm, and when the width is less than or equal to 400mm, the limit deviation is ± 3mm
Note: Take the positive deviation of the cover plate and the negative deviation of the groove bottom width.
3) Tolerance of flatness of bridge surface
Flatness tolerance of hot-dip galvanized protective treatment is not more than 8mm per meter
Electro-galvanized and spray-painted, flatness tolerance of protective treatment is not more than 4mm per meter
4) The vertical height tolerance when the support arm is in the free state is 1/100
5) Other dimensional tolerances according to GB1804-V (the roughest level in the standard)
7. The ground spray bridge should have a good ground. When the bridge is connected with a connection plate, the connection resistance between any unpainted point and the ground terminal is not greater than 0.1 ohm.