Key points for construction of special cable bridge

(1) Construction in sequence Measurement and positioning → Supporting and hanger manufacturing device → Bridge device → Grounding disposal

(2) Primary construction method and skill method

1) Measurement and positioning Mark the device position of the bridge with the elastic wire method, determine the fixed position of the bracket, and make the mark. The positioning of the bridge in the shaft should first be determined by the hanging wire method. If the reserved hole is not suitable, it should be adjusted in real time and repaired. 2) Bracket manufacturing device

3) According to the design elevation of the construction drawing and the specification of the bridge frame, positioning, and then manufacturing the bracket according to the measured size, the bracket is produced in the factory. When there is no suspended ceiling, hoist or lean against the wall bracket device along the beam bottom, and where there is suspended ceiling, hoist or lean against the wall bracket device. In public places without suspended ceilings, connect structural members and think about the beautiful appearance and convenient maintenance, and use the wall, column bracket device or the upper string member upper device on the roof truss. The bracket of the device against the wall is fixed by expansion bolts, and the spacing between the brackets does not exceed 2 meters. Supports and hangers should be added at the joints of straight and non-straight sections, deformation joints of over-buildings, and the middle of non-straight sections with bending radii greater than 300mm. 3) Bridge device

a. Regarding the extraordinary shape of the bridge, the size measured on the spot shall be handed over to the data supplier. The supplier shall manufacture according to the size and reduce the on-site processing. The material, model, thickness and accessories of the bridge frame meet the design requirements.

b. Before the bridge installation, it is necessary to coordinate with various professions to prevent conflicts with large-diameter fire pipes, sprinkler pipes, hot and cold water pipes, drain pipes, air conditioning, and exhaust equipment. c. Lift the bridge to a predetermined position and fix it with the bracket. The size of the bridge should be carefully checked at the turning point. The slope of the bridge should be consistent with the slope of the building. For the bridge of the wall of the arc-shaped building, the arc should match the building Consistent. The bridge frame and the bridge frame are connected by a connecting plate, and the connecting bolt is a semi-circular head bolt, and the semi-circular head is inside the bridge frame. The cracks between the bridges must reach the design requirements to ensure that the bridges of a system are integrated.

d. The bridge spanning the deformation joint of the building should be disposed of the expansion joint according to the enterprise specification "Steel Special Cable Bridge Installation Technology". When the straight section of the steel bridge exceeds 30m, it should be installed with thermal expansion and contraction compensation.

e. The bridge device is horizontal and vertical, beautifully arranged, uniformly spaced, and solidly connected. The degree of uniformity in the plane does not exceed 5mm / m, and the straightness does not exceed 5mm / m. 4) Grounding disposal

Galvanized connecting plates can be used as jumpers between galvanized bridges to connect the bridges into one. Add galvanized spring washers to the two connecting bolts at the two ends of the connecting plate, and connect the bridge with no less than 4mm2 soft copper wire, and then connect the bridge with the ground wire to form an electrical path. There should be no less than two connections between the entire bridge and the grounding trunk.

5) Multi-layer bridge device

For the layered bridge device, the upper layer is installed first, and then the base layer is installed. There should be a margin between the upper layer and the base layer, which is conducive to the later special cable installation and maintenance. The net distance between adjacent bridges should not be less than 50mm, the interval between floors should be at least 150mm according to the width of the bridge, and the distance from the weak current special cable bridge should not be less than 0.5m.