When making reinforcing bars, we should check the processing tables and design drawings, check whether there are errors and omissions in the cutting tables, and check whether each reinforcing bar meets the requirements according to the cutting tables. After these two checks, we can put out the actual samples according to the cutting tables. After trial production, we can make the reinforcing bars in batches. The processed reinforcing bars should be listed and stacked orderly.
If steel bar replacement is needed in construction, it is necessary to fully understand the design intent and performance of replacement materials, strictly abide by various provisions of the current design code for reinforced concrete, and not to replace low strength steel bar with high strength steel bar of equal area. Replacement of reinforcing bars in important parts shall be subject to the consent of Party A and the design unit, and may only be done with written notification.
(1) The surface of reinforcing bar should be clean, and the oil, clay and floating rust must be cleaned up before using, and the rust can be removed by cold drawing process.
(2) The steel bar can be straightened by mechanical or manual means. After straightening, the steel bar must not have local bending, dead bending or wavelet wave shape, and its surface scars should not reduce the section of the steel bar by 5%.
(3) The steel bar should be cut according to the size, diameter, length and quantity of the steel bar, the length should be matched, the long material should be broken first and then the short material should be broken, so as to minimize and shorten the short end of the steel bar, so as to save steel.
(4) Bending or bending of reinforcing bars:
Reinforcement hook. There are three types of hooks: semi-circular hook, straight hook and oblique hook. After bending, the endothelium shrinks, the outer skin extends, the axis length remains unchanged, and the bending part forms an arc. The dimension after bending is not larger than the blanking size, so the bending adjustment value should be considered.
The diameter of bending center of steel bar is 2.5 days and the straight part is 3 days. The theoretical calculation value of increasing the length of steel bar hook is 6.25 days for counter-rotating semi-circular hook, 3.5 days for straight hook and 4.9 days for oblique hook.
(2) Bend the reinforcing bar. The bending diameter D at the bending point of the middle part is not less than 5 times of the diameter of the reinforcing bar.
3. Stirrup. The end of stirrups should be bent hooks, and the form of bent hooks should meet the design requirements. The stirrup adjustment is the difference or sum of the length of the bending hook and the bending adjustment value, depending on the size of the stirrup outsourcing or the size of the inner package.
(4) The length of steel bars should be considered comprehensively according to the size of members, the thickness of concrete cover, the bending adjustment value of steel bars and the length of bending hooks.
A. Cutting length of straight reinforcement = length of member - thickness of protective layer + length of bending hook
B. Cutting length of bending bar = straight length + oblique length - bending adjustment value + hook length increase
C. Cutting length of stirrups = inner circumference of stirrups + adjustment value of stirrups + increase length of bending hooks
Binding and Installation of Reinforcement Bars
Before binding steel bar, be familiar with the drawings carefully, check whether the batching table is different from the drawings and designs, and carefully check whether the finished product size and mind are in accordance with the blanking table. After checking correctly, binding can be carried out.
20 # wire is used to bind bars above 12 in diameter and 22 # wire is used to bind bars below 10 in diameter.
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