Reinforcement planting technology, also known as reinforcement rooting technology, is to drill holes in the original concrete structure, inject structural glue, and insert new reinforcement into the holes by rotation. This technology is widely used in design changes, adding beams, columns, cantilever beams, slabs and other reinforcement and change projects.
Second, the reinforcement bolt anchorage method
1. Before preparing for construction, read the design and construction drawings carefully, and the structural surface must be cleaned. According to the design drawings, the setting-out shall indicate the drilling position of the anchorage point of steel bar, and after indicating the drilling position, the person in charge at the site shall conduct line inspection.
4. According to the requirements of design drawings, specify the anchoring position, aperture and anchoring depth of the drilled bolt.
3. Borehole cleaning
(1). After drilling, clean the dust within a radius of 0.5m around the hole, and clean the hole with an air pump and a brush. This process requires three blows and two brushes, that is, three blows and two wipes. After cleaning, soak the cotton silk in acetone to clean the inner wall of the hole, so that the hole is finally clean and dry; In wet conditions, heating rods must be used for drying.
⑵. If drilling with water: rinse the mud in the hole with clear water, wipe the hole with absorbent cotton, and proceed to the next process after the hole is dry. If the construction period is tight, it can be dried with a heating rod.
(3). Seal the cleaned hole with clean cotton silk to prevent dust and foreign matter from falling in.
(4) The person in charge of the site shall inspect the hole cleaning work, ask the general contractor and the supervisor for acceptance, and make a record of the hidden inspection.
4. Reinforcement cleaning
(1). Mark the corresponding position of the steel bar end, and mark the length range of derusting and cleaning; This length range is required to be 50 mm greater than the required anchorage depth.
⑵. Start the polishing machine, remove rust with a wire brush and clean the surface of the steel bar within the length range until it is polished to metallic luster.
(3) Put the derusted steel bars in a dry place and put them in neat patterns.
(4) Soak cotton silk in acetone, and wipe the surface of steel bar within the length range of derusting and cleaning.
5]. All processed steel bars shall be packed neatly and reported to the person in charge of the site for inspection.
5. Reinforcement embedding.
(1). Preparation of adhesive for steel bar anchorage. (Please refer to the corresponding product description for the specific mixing method, or according to the requirements of the on-site person in charge) Requirements: mix in proportion and stir evenly.
2. Buried in blind hole reinforcement; Inject anchoring glue into 2/3 of the hole; Turn the derusting end of the processed steel bar towards the hole and in the same direction at the same time, and slowly insert the steel bar into the hole until it reaches the bottom of the hole. At this point, if there is no anchor glue overflowing from the hole, it means that the injected glue is not enough, so the steel bar must be pulled out, re-injected and re-inserted until the glue overflows the hole.
⑶. Embedding of through-hole reinforcement: First, insert the processed reinforcement into the hole, and seal both ends of the hole with epoxy mortar. When sealing, one end is reserved with glue injection holes, and the other end is reserved with air holes; High-pressure glue injection can be carried out only after epoxy mortar is solidified. Put the prepared anchoring glue into the glue tube and install the glue nozzle; Injecting 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 block the glue injection hole and air outlet.
(4). When the vertical through-hole reinforcement is planted, the previous steps are the same as Article 3. When injecting glue, the glue should be injected upward from the glue injection port at the bottom of the hole and discharged from the air outlet at the upper part of the hole.
5]. Protect the embedded steel bars and hang obvious signs. In order to prevent the anchoring glue from shaking or colliding during the curing time, the embedding effect is affected.
[6]. Dip the cotton silk in a little acetone, clean up the glue left by the working face, and clean up the garbage on the working face. Note: When cleaning up the residual glue, handle it carefully, and don't shake or bump the steel bar.
Once. Report the inspection to the person in charge of the site.
6. Before the finished protective anchoring glue is cured, the embedded steel bars shall be trimmed and fixed as necessary; Make signs and signs.
Third, stick steel.
The original design bearing capacity and failure resistance of reinforced concrete structural members strengthened with steel plates can be greatly improved after they are bonded with adhesives. This is because after the steel plate is pasted, the reinforcement amount of the original structural member is improved, and the mechanical properties of the structural member in terms of tensile strength, bending strength and shear strength are also improved accordingly, and these properties are guaranteed by the good bonding performance of structural adhesive, which firmly bonds the steel plate and concrete together to form a whole and effectively transmits stress.
Four, outsourcing reinforcement
basic concept
Covered steel is also called bonded steel reinforcement method, and the covered steel of reinforced concrete beams and columns is called covered steel. When glued with latex cement or chemically grouted with epoxy resin, it is called wet ladle reinforcement. It is suitable for the reinforcement of concrete structures that are not allowed to greatly increase the section size of the original members, but require to greatly improve their bearing capacity.
technical characteristics
This method is reliable in stress, simple in construction and less in-site workload, but it uses a large amount of steel and is not suitable for unprotected high temperature places above 600C C. It can greatly improve the bearing capacity of concrete columns without increasing the section size of members.
When the groundwater level is more than 0.8m higher than the design basement, the slightly wet clay soil, sandy soil, collapsible loess, miscellaneous fill and layered fill foundation should be reinforced (heavy hammer compaction method).
Five, paste carbon fiber
Carbon fiber with extremely high tensile strength is pre-impregnated with epoxy resin to become a composite reinforcement (unidirectional continuous fiber); The epoxy resin adhesive is bonded to the structure to be reinforced along the tensile direction or perpendicular to the crack direction to form a new composite material, so that the reinforced bonding material and the original reinforced concrete are stressed together, the crack resistance or shear resistance of the structure is increased, and the strength, rigidity, crack resistance and ductility of the structure are improved.
Construction technology: surface treatment → priming → repair and leveling → preparation of composite materials → sticking carbon fiber → surface protection → inspection.
Structural substitution of intransitive verbs
Structural underpinning technology refers to the functional transformation of the original load-bearing structure that affects the use function of the building by changing the stress system, in order to obtain a more ideal use space. Structural underpinning methods generally include steel underpinning, reinforced concrete underpinning and truss underpinning. Foundation underpinning technology refers to the subway or underground tunnel built in the city inevitably passing under the building. In order to avoid demolition and reconstruction, pile foundation underpinning must be carried out for ground buildings. This technology mainly uses the beam transfer floor near the pile cap to transfer the upper load borne by this pile foundation to the new pile foundation outside the tunnel and replace it with the underpinning structure system composed of underpinning beam and new pile. At the same time, in order to ensure that the underpinning buildings will not be damaged due to cracking and inclination after the broken piles and tunnels pass through, technologies such as prestressed tensioning of underpinning beams, jack-up and grouting at the bottom of piles are adopted, and many patented technologies such as miniature rock-socketed steel pipe cast-in-place piles and concrete interface connection technology can be applied to pile foundation underpinning.
Seven, increase the cross section
Strengthening technology with enlarged section, also known as concrete wrapping reinforcement technology, is to improve the strength, stiffness, stability and crack resistance of members by increasing the section and reinforcement, and can also be used to repair cracks. This kind of reinforcement technology has a wide range of applications, which can strengthen plates, beams, columns, foundations and roof trusses. According to the stress characteristics of members, the requirements of reinforcement purpose, the geometric size of members and the convenience of construction, it can be designed as one-sided, two-sided or three-sided reinforcement and four-sided wrapping reinforcement.
According to the different purposes and requirements of reinforcement, this technology can be divided into enlarging the cross section, reinforcing with steel bars or both. In order to ensure the normal work of supplementary concrete, structural steel bars should also be properly configured for steel bars with larger cross sections. In order to ensure the normal work of reinforcement, the section size should be appropriately increased according to the structural requirements such as reinforcement spacing and protective layer. During reinforcement, steel bars should be welded to make the new and old concrete combine well.