Carbon Fiber Reinforced Column Concrete Structure

Project Description 

This project is a thermal power station with a total installed capacity of 2×1000MW.

Introduction to the structure to be reinforced

This time, the concrete reinforcement construction is required for a structural column of the steam turbine foundation of the thermal power station. The section size of the column is 2710mm×2000mm, and the main reinforcement is 60 steel bars with a diameter of 32mm, as shown in Figure 1.

Reasons for insufficient strength of concrete

(1) The construction period is the rainy season, resulting in high moisture content of aggregates and sand, commercial concrete suppliers did not adjust the concrete mix ratio in time, and the water-cement ratio was too high, resulting in concrete strength lower than the design requirements;

(2) In case of heavy rain during the concrete pouring process, the on-site preventive measures were not timely, and a large amount of rainwater entered the warehouse and concrete mixer truck, resulting in further reduction of concrete strength;

(3) The concrete strength was tested by the rebound method in the later period, and it was found that the concrete compressive strength was 24Mpa, which was difficult to meet the bearing capacity requirements, and concrete strength reinforcement construction was required.

Reinforcing material

HM-30

HM-180C3P

Mechanical properties of carbon fiber materials

The standard value of tensile strength is 4900N/mm2, the tensile modulus of elasticity is 230000N/mm2, the material thickness is 0.167mm, and the elongation at break is 0.021.

Reinforcing the bearing capacity of the front column

Tensile strength of steel bar: 500N/mm2, cross-sectional area of longitudinal steel bar As=0mm2 (because this calculation is only for concrete strength, so the effective area of steel bar is taken as 0), concrete compressive strength is 24N/mm2. The column has bearing capacity:

Column bearing capacity after reinforcement

Pc=0.35Fcc’Ac=58996.7kN

Conclusion: After the CFRP reinforcement construction, the bearing capacity of the column is increased by about 30%, which meets the design bearing capacity requirements.