Chemical Anchor

1. Project Overview

The pier of the Ninghang Expressway NH-NJ1 level bridge gate hub interchange B ramp across the city highway was originally designed to be circular, and the pier has been constructed beyond the road surface of the city highway. Due to various reasons, the design institute requested that the circular bridge pier be changed to a square shape, and a modified drawing was issued. If the entire bridge pier is cut out and re-poured, a large amount of cutting work will cause the construction period to be too long and affect the capacity of the highway around the city. In the design, a technical scheme was selected to cut off the original reserved steel bars and replant the steel bars to connect the new and old structures by planting the steel bars. According to the design requirements, 48 pieces of 32 secondary threaded steel bars need to be replanted on the pier, with a design buried depth of 1280mm and a diameter of 40mm.

2. Introduction to bar planting technology

2.1 Principle of planting bars

Reinforcing reinforcement means that after drilling to the specified depth according to the design hole diameter at the design site, the hole is cleaned, then the reinforcement glue is injected, and the reinforcement is inserted so that the reinforcement and concrete are reliably anchored together by the reinforcement glue. Its anchoring effect is equivalent to that of pre-embedded steel bars, which is a construction technology that meets the requirements of structural transfer of forces.

2.2 Characteristics of planting bars

①High bonding strength, achieving high load force under small aperture and shallow depth:

②The base material is stress-free and can be constructed with small margins and small spacing;

⑤High temperature resistance, can be welded in close range;

④The construction process is simple, the operation is simple, the curing time is short, and the load can be quickly loaded, saving construction time, safe and economical.

3. The main construction technology is based on the specific conditions of the project. The construction sequence is determined as follows: Reinforcement planting location-removing the concrete protective layer of planting rebar-drilling-hole cleaning-glue injection-inserting steel bar-protection

4. Quality inspection and acceptance methods

After the planting is completed, it is very necessary to inspect the quality of planting construction. This project is directed by Nanjing-Hangzhou Expressway to the construction site to conduct a drawing test, and a qualified test report will be issued.

5. Conclusion

The practice of this project has proved that the adoption of the plant-prevention construction technology reduces the ease of construction, simple construction machinery and equipment, and work efficiency. When a certain depth of traceability is reached, the implanted steel bars have a strong torsion and pull force, and there is basically no slippage, so as to ensure that the chain is as strong as pre-embedded (the steel bars can be twisted) and lasting endurance strength (Up to 50 years or more)