by Due to reasons such as improper maintenance or construction quality, houses can have varying degrees of problems, and some serious problems may even endanger structural safety.
Faced with varying degrees of defects in various environments, reinforcement requires the selection of appropriate methods.
Due to the insufficient bearing capacity of components, there are currently many mature reinforcement methods to choose from.
Below, I will introduce several conventional reinforcement methods for components.
“Enlarged section reinforcement method: A direct reinforcement method that increases the section of the original component or adds reinforcement to improve its bearing capacity, stiffness, and stability, or changes its natural vibration frequency.”.
Replacement concrete reinforcement method: A direct reinforcement method that eliminates the concrete in the low strength or defective sections of the original component, and simultaneously pours concrete of the same type but with a higher strength grade for local reinforcement, restoring the bearing capacity of the original component.
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Externally bonded steel reinforcement method: A reinforcement method in which reinforced concrete beams and columns are welded to a frame surrounded by shaped steel and flat steel, and structural adhesive is poured to achieve joint work under overall stress.
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Bonding steel plate reinforcement method: A direct reinforcement method that uses structural adhesive to paste the thin steel plate onto the concrete surface of the original component to form a composite cross-section with integrity to improve its bearing capacity.
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Paste composite fiber material reinforcement method: A direct reinforcement method that uses structural adhesive to paste the fiber composite material onto the concrete surface of the original component to form a composite cross-section with integrity, in order to improve its bearing capacity and ductility.
Application Scope and Advantages and Disadvantages of Component Reinforcement Methods A Chinese medicine hospital was built in 2000.
The building is a reinforced concrete frame-shear wall structure, with 1 underground floor and 12 overground floors (local 13 floors), and a height of 47.05 meters.
Due to the use needs of the owner, it is necessary to change the indoor room layout and room functions in multiple areas of the building, while carrying out overall decoration and renovation of the building.
The load changes before and after the renovation are significant.
According to the appraisal and testing report and relevant design drawings, the building was modeled and checked, and the results showed that: 1) the axial compression ratio of some column members exceeded the limit; 2) the bearing capacity of some column beam plate members did not meet the requirements.
Calculation program for main structure calculation model: YJK2.0.2, calculation program for main structure.
The problems encountered after the renovation of this building mainly include insufficient bearing capacity of components due to increased load and overrun of axial compression ratio of some columns.
Most components only need to improve their bearing capacity, so this reinforcement is mainly based on bonding profiled steel, steel plates, and carbon fiber cloth.
Adopting this series of reinforcement methods to improve the bearing capacity of components has the advantages of short construction period and small impact on building space.
Due to the large increase in load in some areas, the above reinforcement methods are not suitable for the components in this area.
Therefore, the reinforcement method of increasing the cross section or adding a new composite plate that can greatly improve the bearing capacity is adopted for reinforcement.
Various member reinforcement methods: (1) Column member reinforcement: For individual column members whose bearing capacity is not satisfied due to large load increases and whose axial compression ratio is significantly higher, the enlarged section reinforcement method is used for reinforcement, and the remaining columns that need to be reinforced are reinforced with externally bonded steel reinforcement method.
Schematic Diagram for Strengthening with Externally Bonded Profile Steel Reinforcement Diagram for Enlarged Cross Section (2) Reinforcement of Beam Members: Beams that do not meet the bearing capacity requirements are mainly reinforced with beam bonded steel plates.
It is important to note that when using the bonded steel plate reinforcement method for reinforcement, the increase in the flexural bearing capacity of the normal section should not exceed 40%.
For some beam members that require significant improvement in the bearing capacity, the increased cross section reinforcement method is used for reinforcement.
Schematic Diagram of Reinforcement by Bonding Steel Plates Schematic Diagram of Reinforcement by Enlarging the Cross Section of Beams (3) Reinforcement of Plate Members: For plates that do not meet the bearing capacity requirements, carbon fiber cloth is mainly used.
It is necessary to note that the increase in the flexural bearing capacity of the normal section should not exceed 40% when using the carbon fiber reinforcement method for reinforcement.
For plate members that require significant improvement in the bearing capacity, additional composite plates are used for reinforcement.
Due to differences in the scope of application and reinforcement effects of different component reinforcement methods, the selection of reinforcement methods should be determined based on the actual situation of the building.
Comparative optimization of reinforcement methods and selection of reasonable reinforcement methods can achieve the purpose of shortening the reinforcement construction period, reducing investment, and ensuring the reinforcement effect.
Source: Structural Safety Consultant, Guangdong Provincial Academy of Sciences.
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