1. Adding steel bars
Rebar planting technology, also known as steel bar rooting technology, drills holes in the original concrete structure, injects structural glue, and rotates the new steel bars into the holes. This technology is widely used in design changes to add reinforcement and change works such as beams, columns, cantilevered beams, slabs, etc.
2. Reinforcement bolt anchoring method
⒈Construction preparation: Before construction, the design and construction drawings should be carefully read. The structural surface must be cleaned. According to the design drawings, the steel anchorage points are marked by laying out lines. After the drilling position is marked, the person in charge of the site will check the line.
⒉Drill holes to specify the bolt anchoring position, hole diameter and anchoring depth according to the design drawings.
⒊Cleaning the hole
⑴. After drilling is completed, clean the dust within a radius of 0.5 meters around the hole, and use an air pump and a brush to clean the hole. This process must be done in three steps Blow twice, that is, blow the hole three times and clean twice. After cleaning, use cotton wool dipped in acetone to clean the inner wall of the hole to make the hole finally clean and dry; in case of relatively humid conditions, a heating rod must be used , carry out drying treatment.
⑵. If it is water drilling: rinse the mud in the hole with clean water, wipe the hole with cotton wool, and wait for the hole to dry before proceeding to the next process. If the construction period is tight, a heating rod can be used Perform drying process.
⑶. Seal the cleaned holes tightly with clean cotton to prevent dust and foreign matter from falling in.
⑷. The on-site person in charge shall inspect the hole cleaning work, ask the general contractor and supervisor to accept it, and make hidden inspection records.
⒋Steel bar cleaning
⑴. Mark the corresponding position on the end of the steel bar to indicate the length range for rust removal and cleaning; this length range is required to be greater than the required anchoring depth of 50mm.
⑵. Start the polisher and use a wire brush to polish the surface of the steel bars within the length of the rust removal until it reaches a metallic luster.
⑶. Place the rust-cleaned steel bars in a dry place and stack them neatly.
⑷. Use cotton wool dipped in acetone to wipe clean the surface of the steel bars within the length of the rust removal cleaning.
⑸. Place all processed steel bars neatly and report them to the person in charge of the site for inspection.
⒌Reinforcement bar embedding
⑴. Preparation of glue for anchoring steel bars. (Please refer to the corresponding product description for the specific proportioning method, or follow the requirements of the person in charge of the site) Requirements: Prepare according to the proportion and stir evenly.
⑵. If the steel bars are buried in blind holes: Inject 2/3 of the anchoring glue into the holes; turn the treated steel bars with the rust-cleaned end toward the hole, rotate it in the same direction, and Slowly insert the rebar into the hole until it reaches the bottom of the hole. At this time, if no anchoring glue overflows from the hole, it means that the amount of glue injected is not enough. The steel bar must be pulled out, re-injected with glue, and reinserted into the steel bar until the glue can overflow the hole.
⑶. If the through-hole steel bar is embedded: first insert the processed steel bar into the hole, and seal both ends of the hole with epoxy mortar. When sealing, a glue injection hole must be left at one end. Leave an air outlet at the other end; high-pressure glue injection can be performed after the epoxy mortar has solidified. Put the prepared anchoring glue into the glue barrel and install the glue nozzle; inject the anchoring glue into the hole through the glue injection hole until the glue overflows from the air outlet at the other end; then, use epoxy mortar or other materials to The glue injection holes and air outlets are blocked.
⑷. For vertical through-hole reinforcement, the initial steps are the same as item 3. When injecting glue, glue should be injected upward from the glue injection port at the bottom of the hole, and the glue should be injected from the air outlet at the upper part of the hole.
⑸. Protect the embedded steel bars, such as hanging obvious signs. This prevents the steel bars from being swayed or collided during the curing time of the anchoring glue, affecting the embedding effect.
⑹. Use cotton silk dipped in a little acetone to clean up the glue left on the working surface and the garbage on the working surface. Note: When cleaning the remaining glue, be careful and gentle, and do not swing or collide with the steel bars.
⑺. Report to the person in charge of the site for inspection.
⒍Finished product protection: Necessary blocking and fixing of embedded steel bars should be carried out before the anchoring glue is cured; signs and signs should be made.
3. Steel bonding
Using adhesives to bond steel plates to reinforced concrete structural components can greatly improve their original design bearing capacity and damage resistance.
This is because after pasting the steel plate, the amount of reinforcement of the original structural member is increased, which accordingly improves the mechanical properties of the structural member in terms of tensile strength, bending resistance, shear resistance, etc., and these properties are due to the good bonding properties of the structural adhesive. , firmly bonding the steel plate and concrete together to form a whole, effectively transmitting stress and ensuring coordinated work.
4. Outer-wrapped steel reinforcement
Basic concepts
Steel-wrapped reinforcement is also called the bonded outer-wrapped steel reinforcement method, and reinforced concrete beams and columns are called outer-wrapped steel reinforcement. Steel-clad reinforcement. When pasted with latex cement or chemical grouting with epoxy resin, it is called wet steel-clad reinforcement. It is suitable for the reinforcement of concrete structures that do not allow a significant increase in the cross-section size of the original component, but require a substantial increase in its load-bearing capacity.
Technical Features
This method is reliable in force, easy to construct, and requires less on-site workload. However, it uses a large amount of steel and is not suitable for use above 600C without protection. High-temperature places; it can greatly increase the bearing capacity of concrete columns without increasing the cross-sectional size of components.
When the groundwater level is more than 0.8m above the design base, the reinforcement treatment of slightly wet clay soil, sandy soil, collapsible loess, miscellaneous fill soil and layered fill foundation should be carried out (heavy hammer compaction method ).
5. Paste carbon fiber
Pre-impregnate carbon fiber with extremely high tensile strength with epoxy resin to become composite reinforcement material (unidirectional continuous fiber); use epoxy resin binder It is pasted on the structure to be reinforced along the tensile direction or perpendicular to the crack direction to form a new composite body, so that the reinforced pasting material and the original reinforced concrete can bear the same force to increase the crack resistance or shear resistance of the structure. , improve the strength, stiffness, crack resistance and elongation of the structure.
Construction technology: Surface treatment → Apply primer → Repair and leveling → Rubber preparation → Paste carbon fiber → Surface protection → Inspection
6. Structural underpinning
Structural underpinning technology refers to the functional transformation of the original load-bearing structure that affects the building's use function by changing the stress system, with the purpose of obtaining a larger ideal use space. The methods used for structural underpinning are generally steel underpinning, reinforced concrete underpinning, truss underpinning, etc. Foundation underpinning technology refers to the fact that subways or underground tunnels built in cities inevitably pass under buildings. In order to avoid demolition and reconstruction, the buildings on the ground must be underpinned with pile foundations. This technology mainly uses a beam-type transfer layer near the pile foundation of a building that needs to be cut off when an underground tunnel passes through it. The upper load borne by this part of the pile foundation is transferred to the new pile foundation outside the tunnel. Beam - replaced by an underpinning structural system composed of new piles. At the same time, in order to ensure that the underpinning building will not suffer damage such as cracking or tilting after the broken piles and tunnels pass through, technologies such as prestressed tensioning of underpinning beams, pre-jacking, and pile bottom grouting have been adopted. Micro-scale underpinning can be used for pile foundation underpinning. Rock-embedded steel pipe cast-in-place piles, concrete interface connection technology and many other patented technologies.
7. Increasing the cross-section
Increasing the cross-section reinforcement technology, also known as outsourcing concrete reinforcement technology, is to increase the cross-section and reinforcement of the component to improve the strength of the component , stiffness, stability and crack resistance, and can also be used to repair cracks, etc. This reinforcement technology has a wide range of applications and can reinforce plates, beams, columns, foundations and roof trusses. According to the stress characteristics of the component and the requirements of the reinforcement purpose, the geometric size of the component, and the convenience of construction, it can be designed as one-sided, two-sided or three-sided reinforcement, and four-sided wrapped reinforcement.
According to different reinforcement purposes and requirements, this technology can be divided into reinforcement based on enlarging the section, reinforcement based on adding reinforcement, or reinforcement based on both. In order to ensure the normal operation of the additional concrete for reinforcement mainly based on enlarging the cross-section, structural steel bars also need to be appropriately configured. In order to ensure the normal operation of reinforcement, the cross-sectional size needs to be appropriately increased according to structural requirements such as the spacing of steel bars and the protective layer. During reinforcement, steel bars should be welded to combine new and old concrete.