Are steel structure houses safe? What if it's corroded?

With the development of the national economy and the continuous improvement of residents' living standards, the urbanization process is also accelerating. During this process, the construction industry has developed rapidly. Especially in recent years, in order to take into account construction and environmental protection, and to solve the problems of shortage of migrant workers and difficult control of construction quality, the country has vigorously advocated the development of prefabricated buildings. Due to its natural prefabricated properties, steel structures are also being used in prefabricated buildings in various places. Continuing to build. Compared with concrete structures, steel structures have the advantages of light weight, high strength, good plastic toughness, and superior seismic performance. At the same time, steel structures also have certain problems of fire prevention and corrosion resistance. Especially the problem of anti-corrosion, because the general public often sees corrosion or even severe corrosion of many outdoor steel structures, they will have doubts about the corrosion of steel structure houses in 50 years or even longer. So is the corrosion problem of steel structure houses really as problematic as everyone fears? 1. Anti-corrosion design requirements for steel structures As we all know, steel structures are easily corroded in humid environments. Oxygen and moisture in the atmosphere are important factors that cause corrosion of steel structures in civil buildings. Not only that, some industrial gases such as SO2, CO2, NO2, etc. can also cause corrosion of steel structures. The anti-corrosion requirements of building steel structures are not only related to the environmental conditions in which it is located, but also to the specific materials, structural forms, use requirements, construction conditions and maintenance and management conditions of building materials. factors that should be considered. Generally speaking, in the anti-corrosion design, the anti-corrosion design period is first reasonably determined according to the requirements of the importance of the building, environmental corrosion conditions, construction and maintenance conditions, etc., and then comprehensively considers various factors including economy, and adjusts measures according to local conditions. , Reasonable selection of anti-corrosion solutions. It is worth noting that protection should be strengthened in important load-bearing structural components and parts that are difficult to maintain. If they are in a severely corrosive environment, isolation measures such as weathering steel or outsourcing concrete should be used. In the 'Code for Design of Steel Structures', there are clear and detailed requirements for the anti-corrosion design of steel structures. In recent years, for various building forms, different anti-corrosion methods and construction techniques, the state has promulgated and implemented more than ten relevant norms and standards, so that the anti-corrosion design, construction and acceptance of steel structures can be based on evidence. 2. Anti-corrosion scheme of steel structure The existing anti-corrosion scheme of steel structure is roughly divided into the following categories, which can be used alone or in combination in design: Weathering steel Weathering steel is atmospheric corrosion steel, which is between ordinary steel and stainless steel The weathering resistance of weathering steel is 2 to 8 times that of ordinary steel, and the coating property is 1.5 to 10 times that of ordinary steel. It has good rust resistance and is mainly used in railways, vehicles, bridges, towers, and other structural forms that are exposed to the atmosphere for a long time. In building structures, weathering steel also has applications, but is rarely used in residential construction. Figure 1 below shows the Sino-French Center of Tongji University. Its exterior walls and sloping roofs are made of weathering steel. Figure 2 shows the Chicago Civic Center. Its giant steel columns are made of Corten steel, which is also a type of weathering steel. Cathodic protection measures Cathodic protection measures are based on the principle of electrochemistry, adding more active metal to the surface of the steel structure to replace the corrosion of the steel, usually suitable for underwater or underground structures. Anti-corrosion coating&Zinc, aluminum and other metal protective layers formed by various processes Just as you can see that the transmission tower is also of steel structure, but never corroded, the steel structure treated by hot-dip galvanizing has a long anti-corrosion life. The methods of long-term anti-corrosion years include galvanizing, spraying aluminum-zinc, electrophoresis and other methods. 3. Anti-corrosion service life of steel structure residences Although galvanizing, aluminum-zinc spraying and other methods can play a long-term anti-corrosion effect, they are rarely used in steel structure residences due to high cost and other reasons. Generally speaking, the steel structure used in the house is basically painted as an anti-corrosion method. So is the steel structure house as many people worry that it needs to be repainted or anti-corrosion after more than ten years of use?