Overview of structural reinforcement project

The securities business department is a newly built commercial building with a bottom frame structure, originally designed as a shop. The design live load of the floor slab is 2.5 kN/m², and the UPS power distribution room is planned to be arranged here. The equipment in the UPS power distribution room is considered to be 1 t, and distributed in this room to reduce the effect of concentrated forces. Due to the increased load caused by the change of function, the original one-story partial beams and slabs will not meet the design requirements after calculation and need to be reinforced. After program demonstration and economic and technical feasibility comparison, it was decided to use carbon fiber composite materials for reinforcement. The standard value of equipment load at the floor after reinforcement is 2.8 kN/m2, the standard value of other live loads is 2.0 kN/m², and the standard value of ground practice load is 1.0 kN/m².

Repair of reinforced concrete beams using carbon fiber reinforced polymer

In order to strengthen the tracing of the carbon fiber at the bottom of the beam and increase the shear resistance of the beam, 3 strips of 150 mm wide U-shaped lugs were pasted on each side of the beam end and the middle of the span. The height of the U-shaped paste should be taken as the height of the component section. For the U-shaped paste form, it is advisable to paste the longitudinal carbon fiber sheet bead on the upper end.

Construction technology of carbon fiber reinforced polymer repair

Construction preparation---+positioning and laying-off---+substrate treatment---+priming glue---+leveling---+sticking carbon ---+protection

Structural reinforcement materials

The carbon fiber reinforced polymer reinforcement material used in this project is "HORSE CONSTRUCTION" carbon fiber sheet.

Supporting resin type bonding material (adhesive)-HM-180C3P. 

The bonding material is an important guarantee for successful construction. In order to make the reinforced member and the carbon fiber cloth bear the force together, the adhesive is required to have a higher bonding force and strength to the bonded interface and the carbon fiber cloth. The tensile and compressive strength, especially the adhesive shear strength, should be higher than the corresponding strength of concrete. Moreover, the bonding material must have good permeability and compatibility to the interface and the carbon fiber cloth, and it can also resist impact, fatigue, and aging. Generally, it is required that the positive tension strength of the bottom resin and leveling material is greater than 2.5 MPa and not less than the standard value of the tension strength of the reinforced concrete

Conclusion

The project takes less than 10 days from design to completion and put into use, and it is constructed by means of carbon fiber reinfoced polymer reinforcement. It only took 3 days from preparation to completion, and the construction effect was good, which was well received by the design unit, supervision unit and owner. There have been no quality problems in the 3 years since the completion of the project. Therefore, the new technology of pasting carbon fiber reinforced polymer is an effective method to strengthen reinforced concrete structures and is worthy of popularization and application.