Seismic fortification level

Seismic fortification level refers to the level of seismic capacity of buildings in earthquakes, which is usually used to evaluate the safety and stability of buildings. According to the national standard "Code for Seismic Design of Buildings" (GB 50011-2010), buildings are divided into four seismic fortification levels, namely, level I, level II, level III and level IV. Among them, the first level is the highest level and the fourth level is the lowest level.

Building classification standard

According to the requirements of Code for Seismic Design of Buildings, the seismic fortification level of buildings should be determined according to the purpose, height, structural form and foundation conditions of buildings. Specific classification criteria are as follows:

First-class seismic fortification level

The first-class seismic fortification level is applicable to important public buildings, special buildings, large industrial workshops and other buildings, as well as high-rise buildings such as high-rise houses and large commercial complexes. Buildings with seismic fortification level 1 should adopt seismic design, and the seismic fortification capacity should meet the requirements of the code.

Secondary seismic fortification level

The secondary seismic fortification level is applicable to general public buildings, general industrial workshops, residential buildings and other buildings. Buildings with seismic fortification level II should adopt seismic design, and the seismic fortification capacity should meet the requirements of the code.

Three-level seismic fortification level

The three-level seismic fortification level is suitable for general industrial workshops, ordinary commercial buildings, low-rise residential buildings and other buildings. Buildings with seismic fortification level 3 should adopt seismic design, and the seismic fortification capacity should meet the requirements of the code.

Four-level seismic fortification level

The four-level seismic fortification level is suitable for buildings such as simple farmhouses and simple industrial workshops. Buildings with seismic fortification level 4 may not be subjected to seismic design, but should meet the seismic fortification capacity required by the code.

How to carry out seismic fortification?

In order to improve the seismic capacity of buildings, a series of measures need to be taken in the process of design, construction and maintenance. The following are some common seismic fortification measures:

1. Seismic design

In the architectural design stage, seismic design should be carried out according to the purpose, height, structural form and foundation conditions of the building. The seismic design should meet the requirements of the code to ensure that the building has sufficient seismic capacity during the earthquake.

2. Seismic reinforcement

For the built buildings, the seismic capacity can be improved by strengthening. Strengthening methods include increasing the strength and stiffness of the structure, strengthening the connection parts, strengthening the wall and so on.

3. Foundation reinforcement

Foundation is the foundation of a building, and its stability has a vital impact on the seismic capacity of the building. Therefore, in areas with poor foundation conditions, foundation reinforcement is needed to improve the stability and seismic capacity of buildings.

4. Regular inspection and maintenance

The seismic capacity of buildings is not static, it will gradually decrease with the passage of time. Therefore, it is necessary to inspect and maintain the building regularly, find and deal with the existing problems in time, and ensure that the seismic capacity of the building is always at the level required by the code.