Steel Structure Instability And Corrosion

The important structures which are easy to occur load change adopt hyperstatic structure, such as bridge, truss, sluice gate and missile launchers. Because they have redundant bar which can prevent that a member instability cause the overall instability.

Steel structure instability can be divided into two categories. They are overall buckling and local buckling. The overall instability mostly caused by partial instability. When the compression part or bending parts of the slenderness ratio exceeds the allowable value, it will lose stability. Many objective factors will have effect on it, such as loading changes, initial defect of steel and different support. The support is often neglected by designers and constructors. It is also one reason to cause overall instability. Truss or bar stress may change, and even resulting in instability because of different hanging position. Scaffolding collapse, collapse or deformation are mostly caused by no support or link deficiency.

If instability is acute disease, corrosion will be a chronic disease. Anti corrosion performance of ordinary steel is bad, especially for staying in the environment which has high humidity and corrosive medium. Because it usually will be rust and corrosion quickly.

Reinforcement Technology Of Steel Structure Damage

If there are some damages in steel structure, we need solve problem in time. There are five factors that caused steel structure damage. Firstly, the load changed, the service extended, rules and regulations changed. Secondly, structure deformation,twist,disability or depression with various accidents. And it also section weaken, rod warping, connection cracking. Thirdly, component or connection deformation, cracking and warping which caused by temperature effects. Chemical corrosion make the section of steel structure weaken. Certainly, other illegal use and operation will lead to damage.

There are three reinforcement method to steel structure. They are section reinforcement, change the calculation diagram and prestressed cable method. Section reinforcement is using the steel to reinforcement in local or along the member length. The method of changing calculation diagram is that adding support, adjust load distribution,reduce stress levels, decrease the stress peak. Prestressed cable method is that strengthening weak links with high-strength cable or improving the whole structure bearing capacity, rigidity and stability.

Once the earthquake occurred, we must first maintain a clear, cool headed and determine shock condition promptly. Don’t jump off building in panic. This is very important. Besides you can hidden under solid furniture or corner. Certainly you can also transferred to the kitchen which has small hall and many load-bearing walls or even toilet. Because these places has strong combining power, especially the pipe has good support force after some treatment, and seismic coefficient is larger.