1) General principles for concrete structrual strengthening the impact of the program

To determine the old building strengthening plan, we must first thoroughly study the relevant content of the building inspection and appraisal conclusions. Secondly, carefully analyze the internal force of the structural members to ensure the overall effectiveness of the concrete structrual strengthening. In order to make the new and old parts of the reinforced structure cooperate with each other, an effective reinforced building process or structural treatment method can be used, relying on the connection between the old and new combined membranes, and at the same time adversely affect the original structure and the new structure, and can avoid defects.

2) Principle of overall influence of structural system

There are many building components, such as beams, slabs, columns, frames, walls, etc. Each component is indispensable. Once a problem occurs, it needs to be repaired and strengthened in time. In the process of concrete structrual strengthening, avoid "headaches and feet aches and feet". Concrete structrual strengthening is not only aimed at weak links, but also should consider the impact of reinforcement on the entire structural system. For example, the reinforcement of certain structural components sometimes adversely affects the seismic properties of the structure by changing the dynamic characteristics, creating relatively weak layers or transporting weak components.

3) Carrying capacity verification principle

Consider the synergy of the old and new structures. In the design, the stress conditions of the new and old structures should be considered. Because the newly added components are subjected to secondary forces, the stress delay of the newly added components and the decrease in material strength must be considered when calculating the load. If the overall quality of the foundation changes significantly, its bearing capacity must be calculated.

4) Seismic requirements

In my country, most houses built before 1980 do not consider seismic reinforcement. However, for houses built before the 1990s, the degree of seismic reinforcement is higher than 7 degrees. Existing seismic reinforcement projects should also consider the issue of seismic protection, and the reinforcement design must meet the requirements of bearing capacity. On the other hand, it should also meet the relevant requirements of the "Code for Seismic Design of Buildings" (GB50011-2010) to meet the corresponding seismic requirements. Therefore, new weak layers with sudden changes in stiffness or large local changes should be avoided after reinforcement.

5) Concrete structrual strengthening material selection and value

When selecting concrete structrual strengthening reinforcement materials, try to select those that are compatible with the original structure, so that it has the greatest adaptability and good performance. The strength grade of reinforced concrete should generally be increased by one level on the basis of the original structure. The concrete strength grade of the superstructure should not be lower than C20, the selected cement strength grade should be greater than 32.5, and the steel bar strength grade is usually the original concrete member, depending on the design specifications. The strength of the chemical grouting material and the strength of the bonding material should be more high.

6) Principles of optimization and concrete structrual strengthening

The selection of concrete structrual strengthening reinforcement methods should follow certain principles to avoid blindly misusing reinforcement effects. Consider the impact of reinforcement on the structural system in the structure itself to ensure that the reinforced structural system meets the requirements of the specification and effectively improve the safety factor. Secondly, factors such as concrete structrual strengthening cost, construction period, environmental impact and reinforcement cost, service life and construction difficulty should also be considered. .