Old building retrofitting

Applications project

The air-conditioning main room of an old building renovation project is limited by site design and is located on the first floor of the building, below which is the underground garage. Taking into account the weight of the air-conditioning main engine and the water pump and the effect of the long-term fatigue load on the original floor slab, in order to ensure safety, the load bearing capacity of the original structure was checked. The result of the review is that the original structure cannot meet the load requirements, and it is necessary to reinforce multiple structural beams in the air-conditioning room. 

The performance indexes of the bonded steel reinforcement method and the carbon fiber reinforcement method are relatively close, but the fatigue resistance of the carbon fiber method is better than the bonded steel method. And because of considering that there are many types of pipelines blocking the site to be reinforced on site, the operation space is narrow, so the carbon fiber reinforcement method was finally selected.

Strengthening materials

The thickness of carbon fiber cloth is 0.111mm. Choose two layers of 300mm wide carbon fiber cloth on the bottom of the beam. In order to strengthen the anchorage of the carbon fiber cloth at the bottom of the beam and increase the shear resistance of the beam, three 100mm wide U-shaped hoops are pasted on each side of the beam end.

In conclusion

The project has a duration of 8 days and it has been three years since the completion of the project. During the return visit, no quality problems were found. Engineering practice has proved that the carbon fiber reinforcement technology is very ideal for the reinforcement and reinforcement of concrete structures and components. Without basically increasing the cross-sectional size and weight of the beam, the technology has met the owner's requirements in terms of construction period, material durability, and construction quality. Its comprehensive economic and social benefits are good, and it has a large value for promotion and use.

At present, due to more applications and mass production of carbon fiber products, the construction cost of carbon fiber cloth has dropped significantly. However, the price-to-price ratio has been further improved, and it is foreseeable that the carbon fiber cloth reinforcement method will be more and more widely used.