What are the principles and methods of steel structure reinforcement design?

When the steel structure needs to be reinforced by reliability appraisal, professional and technical personnel should be based on the conclusion of reliability appraisal and the requirements of the client, in accordance with the requirements of the national standards for reinforcement design, the content and scope of reinforcement design can be the whole structure, or local structure. .Specific parts or components. The reinforcement design of steel structure should pay attention to the close combination of reinforcement design and construction methods, and take effective measures to ensure the new cross section. The components are reliably connected to the original structure to form a whole working together to avoid adverse effects on unreinforced parts or components. Generally speaking, the main method of steel structure reinforcement is to reduce the load. Change the calculation graph. Increase the cross section and connection strength of the original structural members. Prevent crack propagation, etc. In the case of mature experience, other methods can also be used to strengthen the steel structure.

Change the structure calculation graphic reinforcement method: refers to the use of changing the load distribution state. Force transfer path. Add node properties and boundary conditions for additional rods and supports. Prestressing. Taking into account measures such as spatial collaborative work to strengthen the structure, the general reinforcement methods are as follows:

For the structure, it can be used: add support to form a spatial structure, and calculate according to the spatial structure. Increase the structural stiffness, or adjust the natural vibration frequency of the structure to improve the structural bearing capacity and improve the dynamic characteristics of the structure. The addition of support or auxiliary rods reduces the slenderness ratio of the structure to improve its stability. The main point is to strengthen the stiffness of one column in the shelving structure so that it bears most of the horizontal force, thereby reducing the load on the other columns. In order to enhance the stiffness of the structure, a tension rod or moderately tensioned cable is set in the steel structure such as the tower.

For bending members, you can: change the distribution of loads, such as converting one concentrated load into multiple concentrated loads. Change the support condition of the end, for example, change the hinge to the rigid knot. An intermediate support is added or the end of the simply supported structure is connected into a continuous structure. Adjust the position of the support of the continuous structure. Change the structure to a strut structure. Prestressing is applied.

The method of strengthening the section of the component involves a wide range of areas, and the construction is relatively simple. Under certain conditions, the construction treatment can be carried out under load. The main method is bonding steel reinforcement. When adopting this method for steel structure reinforcement, the force of members and the defects of the structure itself should be considered. Under the premise of convenient construction, the effective form of increasing section connection is selected to achieve the reinforcement effect. Repair and reinforce cracks: structures due to the repeated action of loads and the choice of materials. Construction. Manufacturing. If the construction and installation of improper expansion or brittle fracture tendency crack damage, should be repaired as far as possible. Before repair, it is necessary to analyze the cause of the crack and the severity of its impact, and take targeted measures to improve the actual work or reinforcement of the structure. Parts that are not suitable for repair and reinforcement should be removed and replaced. In our country, the introduction of fiber composite reinforcement method is still relatively short, but it has shown its advantages and become a scientific research institute. The hot spot of university research, and has been widely used in practice. In particular, the adhesive fiber reinforcement method is more mature, and its application is more extensive than the prestressed fiber reinforcement method and the embedded fiber reinforcement method.

From the current research situation, the common problems to be solved by these three fiber reinforcement methods are mainly in the following aspects:

Study on long-term mechanical properties of fiber reinforced components and fiber reinforced joint properties;

2. At higher temperatures, the strength of the fiber reinforced structure deteriorates seriously. How to improve the performance of reinforced materials and the measures of fire and temperature resistance of reinforced components is a topic to be studied.

How to simplify the construction process, strengthen the quality assurance and reduce the project cost is a very urgent matter.

In short, in order to ensure the normal design. In the use stage, the construction unit should regularly check or maintain the reliability of the steel structure, and if necessary, entrust professional organizations to carry out reliability evaluation to ensure the safety of the steel structure. Suitability and durability. In recent years, with the development of science and technology, new reinforcement materials and reinforcement methods have appeared, and these technologies have obvious advantages and have been widely used. However, this does not mean that new methods and new technologies can replace traditional methods. At the same time of developing new technologies, it is necessary to supplement the advantages and disadvantages of various reinforcement methods, supplement the advantages and disadvantages of various reinforcement materials, develop reinforcement technology, and provide practical and reliable technical support for building reinforcement.