Reinforcement engineering construction process control procedures?

Quality assurance of steel bars

① The factory certificate should be provided by the quality inspection department of the steel plant or copied by the supply and marketing department. The content of the certificate: manufacturer name, furnace tank number (or batch number) , steel type, strength, grade, specifications, weight and number of pieces, production date, factory batch number; mechanical property inspection data and conclusions; chemical composition inspection data and conclusions; and the seal and standard number of the steel plant's quality inspection department. The name of the unit's project and the location of use should be written by the construction unit in the remarks column of the factory certificate (or its transfer or copy).

② The test report should be provided by the statutory testing unit. The content of the test report: entrusting unit, project name, use location, steel bar grade, steel type, steel number, appearance mark, factory certificate number, representative quantity, delivery Sample date, original record number, report number, test date, test items and data, conclusion (the elongation index should indicate the gauge length, and the cold bending index should indicate the bending center radius, bending angle and bending result)

The batching of steel bars

The batching of steel bars is based on the component reinforcement diagram in the design drawing. First, simple drawings of individual steel bars of various shapes and specifications are drawn and numbered, and then the cutting lengths of the steel bars are calculated respectively. and the number of steel bars, fill in the batching list, and only after the review is correct, the steel bar can be cut and processed. Therefore, a correct batching list not only guarantees the accuracy of steel bar processing and forming, but also prevents the ends of the steel bars from appearing during the installation of the steel bars. Problems such as insufficient extension and insufficient anchorage length ensure the quality of the steel bar project. Therefore, the steel bar batching work must be carefully reviewed and strictly controlled.

Blanking and processing of steel bars

All the cutting and processing of steel bars in this project are carried out at the on-site processing site, so that the length can be matched and the materials can be cut reasonably, which can improve the quality of the steel bars. Product yield.

(1) Steel bar rust removal: The surface of the steel bar should be clean, so rust must be removed before cutting the steel bars. Remove the oil stains, paint stains and loose skin that can peel off when struck with a hammer. Rust removed. The rust removal of the round steel bars is completed during the cold drawing and straightening process; the threaded steel bars are completed with a self-made electric rust remover, and a dust collector is installed to avoid damaging the workers' bodies and polluting the environment.

(2) Steel bar straightening: Use a winch with a pulling force of 3 tons and ground anchors at both ends to cold draw to straighten the steel bars. According to the requirements of the construction specifications; the cold drawing rate of grade I steel bars It should not be greater than 4%; the cold drawing rate of grade II steel bars should not be greater than 1%. After straightening, the steel bars should be straight without any local bends.

(3) Steel bar cutting: Steel bar cutting equipment mainly includes steel bar cutting machines and toothless saws, etc., which will be selected according to the diameter of the steel bar and the specific situation.

Cutting process: Match steel bars of the same specifications according to their lengths, and arrange the materials as a whole. Generally, long materials should be cut off first, and then short materials should be cut off to reduce short ends and losses. When cutting off materials, avoid using short rulers to measure long materials to prevent accumulated errors in measuring materials. For this reason, it is advisable to mark the size scale on the workbench and set up baffles to control the size of the cutting materials. During the cutting process, if any cracks, shrinkage or severe bends in the steel bars are found, they must be removed.

Bending and forming

(1) Bending equipment: Steel bar bending and forming is mainly completed by the combination of steel bar bending machine and manual bending tools.

(2) Bending forming process: Before bending the steel bars, for complex-shaped steel bars, use a stone pen to mark out the bending point positions according to the dimensions indicated on the ingredient list. The marking work should be carried out from the center line of the steel bar to both sides; if the steel bars are asymmetrical on both sides, the marking can also be started from one end of the steel bar. If there is a discrepancy between the marking and the other end, it should be readjusted. After checking the dimensions of the scribed steel bars, they can be processed and formed.

Reinforcement joints

Reinforcement joints are an important part of the entire steel project. The quality of the joints is the key to ensuring normal stress bearing. Therefore, the form of steel bar joints should be carefully selected, and the selection principles are: reliable, convenient and economical. This project will be selected on a case-by-case basis.

(1) Joint method This project gives priority to the convenient and fast flash butt welding and electroslag pressure welding as the joint method. Frame column diameters ≥φ18 are connected by electroslag pressure welding, and <φ18 are connected by lashing and lap joints. Frame beams ≥φ18 are connected by flash butt welding.

(2) Joint positions: The joint positions of steel bars should be arranged in accordance with the design requirements and construction specifications 03G329 (1) and 03G101.

The upper steel bars of the base plate are connected at the support joints, and the lower steel bars are connected at the mid-span; the upper joints of the frame beam plate bars are within 1/3 of the mid-span, and the lower steel bar joints are at the supports; the steel bar joints of the columns are densely packed at the top of the beam or the upper column. Above the stirrups.

(3) Flash butt welding and electroslag pressure welding construction process a) Flash butt welding process: using AC welding machine, first use flash-preheating-flash welding process, the main process includes one During flashing, preheating, secondary flashing, and upsetting processes, rust and sludge within the end range should be removed before butt welding. Curved ends should be straightened or cut off in advance. When changing welders or replacing steel bars, they should be made first. The sample can be welded only after passing the test. When clamping the steel bar, the two protruding end surfaces of the steel bar should be in contact to facilitate uniform heating and ensure that the axis between the two steel bars is consistent. After the welding is completed, the joint should turn from white to black. Only when it turns red can the clamp be loosened, the burrs and curling edges at the joints should be removed, and the welding site should be protected from rain and wind.

b) Electroslag pressure process: Its main process includes arc starting, arc, electroslag and top pressure processes. The arc ignition adopts the direct arc ignition method, that is, after energizing, the upper steel bar is quickly lifted to keep the two ends 2-4mm; the arc uses high temperature to burn the ends, and at the same time melts the surrounding flux to form a slag pool; after the slag pool is formed , slowly insert the upper steel bar into the slag pool, extinguish the arc, and perform the electroslag welding process. If welding defects such as axis deviation, joint bending, poor bonding, burning, and slag inclusions are found during the welding process, the cause should be identified and measures should be taken to remove them in time.

Stacking and transportation of steel bars

(1) The stacking of steel bars is based on the actual conditions of the project site. The steel bars are made at the on-site processing site. The steel bars must be laid according to their specifications, diameters and forms. Different materials should be stacked neatly and marked with signs to make them neat and clear for easy search and use. They should be temporarily stacked close to the construction site according to the signs. (2) Transportation of steel bars In order to speed up the construction progress, the steel bars at the construction site of this project are transported using derricks. When transporting steel bars on the derrick, test lifting of longer steel bars should be carried out to find the correct lifting point. If necessary, square wood or long steel pipes can be used to strengthen it. It is strictly forbidden to make the lifting point distance too large, which will cause the steel bar to bend and deform.

Reinforcement bar binding and installation

(1) Preparation work Prepare a sufficient number of mortar pads to ensure the thickness of the protective layer of the steel bars. Because the board reinforcements are double-layer steel bars, a sufficient number of steel horse benches must be configured. Different horse benches are used due to different thicknesses of the boards. For the thicker floor, a herringbone horse stool is used. The horse stool is made of Φ16 steel bars, with herringbone legs at both ends, and the distance is 600. If the floor thickness is small, the horse stool can be made of Φ12 steel bars. The horse stool should be placed on the bottom mesh. The horse stool is made as shown in the picture below. ?Is there any steel bar higher than the plate)→Tie the iron horse stool and the upper steel bars→Place the fixed reserved hole mold→Seal the construction joints→Self-inspection and special inspection→Report to the supervisor for hidden inspection→When the longitudinal bars of the handover inspection beam are arranged in double layers, Short steel bars with a diameter of ≥25mm should be placed between the two rows of steel bars to maintain the designed distance. Stirrup joints should be arranged staggered on the two erecting steel bars. The reinforcement range of beam stirrups must meet the design requirements. When the floor slab and secondary beam steel bars need to be extended, the upper bars are overlapped at mid-span, and the lower bars are at the supports (4) Binding of pool wall steel bars. Wall steel bar binding construction process: pop up the wall section dimension line and the outer edge line of the formwork → Pre-inspection line → Check and adjust the position of the vertical bars → Overlap and tie the horizontal bars of the vertical bars → Install protective layer pads → Self-inspection and special inspection → Submit inspection for hidden inspection → The vertical steel bars of the wall should be placed before pouring the floor concrete. Insert and tie firmly with the hidden beam at the bottom of the wall. The wall steel bar joints should be staggered, the joint rate of the same cross-section should not exceed 50%, and the steel bar overlap should be tied with three buckles. The wall is a double-layer steel mesh, and horizontal ladder bars are used to ensure that the distance between the two mesh pieces is fixed. When tying the wall steel mesh, the hooks of the steel bars should be directed into the concrete wall.

(5) Column steel bar tying construction process for tying frame column steel bars: pop up the column section dimension line and template outer edge line → pre-inspection line → check and adjust the position of the vertical bars → connect the vertical bars → tie the columns The stirrups control the overall verticality of the column → the protective layer of the binding column → self-inspection and inspection → report to the supervisor for hidden inspection → handover inspection with the formwork construction personnel office The joint rate is no more than 50%. When tying the stirrups of columns, their joints should be arranged in a staggered manner, and the intersection points of the stirrups and vertical bars should be tied firmly in a figure-eight shape. Before pouring concrete, positioning ferrules are welded to the top of the column bars to control the spacing of the steel bars to avoid displacement of the steel bars when pouring concrete. The position of column stirrups must be accurate, and the range of stirrup encryption should meet the design requirements.

After the column reinforcements are tied, the mortar pads should be tied in time.

(6) The steel bars in the post-cast belt shall be reinforced in strict accordance with the design requirements. It is strictly prohibited to leave steel joints in the post-cast belt. The steel bars in the post-cast belt must have protective measures to avoid contamination and corrosion.

For more information about engineering/service/purchasing tender document writing and production to improve the bid winning rate, you can click on the official website customer service at the bottom for free consultation: /#/?source=bdzd