1. Rebar cage fabrication should be carried out in a hardened rebar area to ensure smooth binding and welding of the processed rebars.
2. The lap joints of the reinforcing bars should be double-sided welded, with a lap length greater than or equal to 5 times the diameter of the rebar to ensure a strong connection.
3. Rebar cage joints should be staggered, and the number of joints on the same cross-section should not exceed 50% of the total number to increase structural stability.
4. After the rebar cage is fabricated, its stiffness and stability need to be measured. If necessary, the number of reinforcing stirrups should be increased, and cross braces should be welded inside the stirrups to ensure sufficient stiffness and stability during transportation, hoisting, and concrete pouring, preventing loosening, displacement, or deformation.
5. During welding, the electrode coating decomposes and melts, forming gas and slag, which protect the welding area and help deoxidize and purify the molten metal. As the electric arc moves, the workpiece and weld core continuously melt, forming a new molten pool. The original molten pool cools and solidifies as the arc moves away, forming a weld, thus connecting the two workpieces into a single unit.
Note:
1. For shorter pile foundations, the reinforcing cage can be fabricated as a single unit for successful hoisting in one go.
2. When fabricating the reinforcing cage, appropriate jigs must be used, and the spacing and straightness of the reinforcing bars must be strictly controlled.
3. When lap welding the main reinforcing bars in a segmented reinforcing cage, the reinforcing bars should be pre-bent, ensuring that the number of joints on the same section does not exceed 50% of the total number of main reinforcing bars, and the distance between two joints is not less than 500mm. Main reinforcing bar welding should be single-sided, with a weld length of not less than 10d.
4. Stirrups should be double-sided welded, with a weld length not less than 5 times the stirrup diameter, and can only be overlapped vertically, not radially. The connection between the reinforcing stirrups and the main reinforcing bars should be spot welded.
5. During transportation, the reinforcing cage must be reinforced to prevent rolling and to ensure its shape is not damaged.
6. After the reinforcing cage is installed in place, the descent speed should be controlled to avoid scratching the hole wall.
