In the design of light steel structure, the strength after web buckling is considered, which can reduce the setting of stiffeners and reduce the amount of steel, which is light steel structure. Otherwise, there will be a lot of steel, that is, heavy steel structure.
1. Lifting weight of powerhouse crane: 25 tons or more, which can be considered as heavy steel structure.
2. Steel consumption per square meter: greater than or equal to 50kg / ㎡, which can be considered as heavy steel structure.
3. Steel plate thickness of main components: 10mm or more, less for light steel structure.
In addition, there are some reference values: such as cost per square meter, maximum component weight, maximum span, structural form and eaves height.
The above can provide empirical data when judging whether the plant is heavy steel or light steel. Of course, many buildings are light and heavy steel.
But some we can say with certainty are heavy steel: such as petrochemical plant facilities, power plant plants, long-span stadiums, exhibition centers, high-rise or super high-rise steel structures.
In fact, there is no “heavy steel” in national specifications and technical documents. In order to distinguish the steel structure of light houses, it may be more appropriate to call the general steel structure “ordinary steel”.
Because the scope of ordinary steel structure is very wide, which can include all kinds of steel structures, regardless of the load, and even many contents of light steel structure, the technical specification for steel structure of light house only stipulates some more specific contents according to its “light” characteristics, and the scope is only limited to single-layer portal frame.
Light steel is also a vague term, which can be understood in two ways. One is the “light steel structure of round steel and small angle steel” in Chapter XI of the current code for design of steel structures (GBJ 17-88), which refers to the light steel structure made of round steel and angle steel less than L45 * 4 and L56 * 36 * 4
It can be seen that the difference between light steel and heavy steel is not in the weight of the structure itself, but in the weight of the supporting materials, but in the concept of structural design.
Taking the steel structure plant as an example, the hoisting adopts the principle of “first the middle, then the outer side, first the column and then the beam, first the lower part and then the upper part”, first form a stable frame system in the middle part of the plant, then push towards both ends and install the remaining steel columns and steel beams symmetrically, in the following order:
Retest of anchor bolts → unloading of steel components → mobilization inspection of components → direct hoisting of truck crane in place → temporary fastening of anchor bolts → temporary tension and stability of cable wind rope → adjustment of steel column axis position and verticality → fastening of steel column bolts and column base pressing plate Welding → installation of the next steel column → installation of tie bars between steel columns → formation of the first stable lattice system → assembly of steel roof truss into a whole on the ground and lifting in place by two machines to form the first steel roof truss → symmetrical installation of columns and roof truss system on both sides →… → analogy → completion of steel structure installation and structural acceptance.
1. Safe and reliable
The housing with steel as the main building material has high bearing capacity per unit volume, is more stable and firm than the traditional brick wood and brick concrete technology, has better seismic performance, wind resistance, waterproof and fireproof performance, and also has heat insulation and sound insulation functions.
Steel has good ductility and can better consume the energy brought by earthquake, so it has good seismic performance and high structural safety, which ensures the safety of residence.
2. Simple construction and short construction period
All components are prefabricated in the factory and only need to be assembled on site, which greatly shortens the construction cycle. A 6000 square meter building can be basically installed in 40 days.
3. Durable and easy to repair
The steel structure building designed by general-purpose computer can resist bad weather and only needs simple maintenance.
4. Beautiful and practical
The lines of steel structure buildings are simple and smooth, with a sense of modernity.
The color wall body has a variety of colors to choose from, and the wall can also use other materials, so it is more flexible.
5. Green environmental protection and sustainable development
All houses have a certain service life. Generally, the raw materials removed from the houses with brick concrete structure can not be reused, and a large amount of garbage will be generated to pollute the environment.
The steel of steel structure residence can be 100% recycled to realize recycling. It has less environmental pollution during construction and demolition, which meets the requirements of housing industrialization and sustainable development.
1. The cost is relatively higher than that of traditional brick concrete and steel concrete.
2. With its unique steel framework, wall, roof and other materials, as well as standardized and finalized internal layout and supporting facilities, steel structure residence is difficult to adapt to the habit of “arbitrary treatment” of housing.
3. Corrosion of steel: aluminized and zinc plated steel must be used to prevent corrosion to the greatest extent, and the main steel structure can reach 50 years.
4. There are many requirements for new materials. The structure of steel residence is equipped with thermal insulation and other materials, and light new building materials will be widely used.
