Reinforcement engineering involves the installation of steel bars in various structural components. It is crucial to follow proper construction methods to ensure the overall quality and durability of the structure. Below, we outline the key quality control points for steel reinforcement construction in different parts of a building.
1. Foundation
1. The concrete protective layer thickness for longitudinally stressed steel bars in foundations must meet design specifications, with a minimum thickness of 40mm. If no concrete cushion layer exists, the thickness should be at least 70mm.
2. When binding the basic steel mesh, all intersection points along the outer two rows of steel bars must be securely tied. Intersection points in the middle rows can be staggered and tied, but it is essential that the stressed steel bars remain immobile.
3. For independent column foundations with two-way steel bars, the steel bars on the shorter side at the bottom should be placed beneath those on the longer side. In this case, all steel bar intersections must be tightly tied.
4. When using a double-layer steel mesh for the foundation bottom plate, steel or concrete supports should be placed beneath the upper layer of mesh at intervals of approximately 1 meter, ensuring the steel reinforcement structure maintains its correct position.
2. Beam
1. After tying the beam reinforcement, protective cushion blocks (commonly marble) should be promptly placed at the intersections of hoop reinforcement and main reinforcement at the bottom.
2. Beam-column nodes typically have dense reinforcement. During binding, first insert the bottom reinforcement, then bind the column hoop reinforcement, and finally insert the beam’s top reinforcement.
3. The intersections of main reinforcement, waist reinforcement, and hoop reinforcement must be tightly tied, with screws in alternating directions across the upper and lower rows to prevent deformation of the beam framework.
4. Since binding joints are relatively weak under external forces, they should be located in low-stress areas of the component. For example, in simply supported beams, tensile steel bar joints should be positioned within the outer quarter spans of the beam, at least 10 times the diameter of the steel bar away from the bending points.
3. Wall
1. When using double-layer steel mesh in walls, braces (hooks) should be installed between the two layers of steel bars to maintain consistent spacing.
2. During binding of interior and exterior wall steel mesh, horizontal steel bars should be positioned outside the main bars. If the steel bars have 90° hooks, these hooks should face the interior of the concrete.
3. After completing surveying, the main reinforcement should be bent at a 1:6 ratio according to the wall or column boundaries and control lines. Once adjusted in place, stirrup installation and binding can proceed.
4. Before binding wall or column steel bars, elevated stools must be set up around the wall. All workers should perform steel bar binding from these stools to ensure personnel safety.
4. Column
1. The bending hooks of longitudinal steel bars should face the center of the column. Positioning clamps or hoops should be installed inside the column to ensure accurate placement without deformation.
2. The exposed steel bars at the bottom of the column should be clamped with tool-type column clamps that fit the bar diameter, facilitating overlap with the steel bars of the upper column.
3. If the column cross-section changes, the exposed lower column reinforcement must be precisely contracted before binding the beam reinforcement.
4. Reinforcing bars that connect cast-in-place columns to foundations must be securely fixed and accurately positioned to prevent displacement of the column axis.
5. Slab
1. Before binding slab steel bars, lines should be drawn according to the spacing requirements of the lower bars. Using an ink fountain, a square grid is formed. All intersection points along the outer two rows of steel bars must be firmly tied, while interior intersections can be staggered and tied, ensuring the stressed steel bars remain fixed.
2. Negative reinforcement on the slab’s upper side must be protected from foot traffic, especially on cantilever slabs such as canopies, eaves, and balconies. The positioning of negative reinforcement requires strict control, with cushion blocks and supports placed as needed to prevent damage after formwork removal.
3. Supports (horse stools) for reinforcement should not be installed directly on the formwork surface. Instead, they must rest on the bottom reinforcement, with protective cushion blocks placed at the intersections where supports are installed.
4. For double-layered steel mesh, steel reinforcement support feet should be positioned beneath the upper mesh layer to maintain the correct reinforcement placement.
Source: Architectural Technology Magazine
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