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.
Light steel is a rather ambiguous term and can generally be understood in two ways. One is the current “Code for the Design of Steel Structures” (GBJ 17-88) in chapter 11 “round steel, small angle steel light steel structure”, refers to the use of round steel and less than L45 * 4 and L56 * 36 * 4 angle steel made of light steel structure, mainly in the steel lack of years when used inappropriate to use The steel design code has been largely revised to remove the tendency of small structures that are not suitable for reinforced concrete structures. The other is the “portal frame light house steel structure technical regulations” with light roof cover and light external walls (can also be conditional on the use of masonry external walls) of the single-storey solid web portal frame structure, where the light mainly refers to the envelope is with light materials. Since the former has almost been abolished, the meaning of light steel now mainly refers to the latter.
Light steel structure is a light steel construction system, which is a light, fully assembled steel building based on hot-rolled light H steel, light welded steel, high-frequency welded steel, cold-formed thin-walled steel, thin steel plates and thin-walled steel pipes and other high-performance structural steel and highly functional materials, supplemented by various types of highly effective decorative connection materials to meet the specific use of building functions and specific space requirements.
The difference between steel structure and steel structure is the difference between heavy steel structure and light structure, there is also no a unified heavy steel structure and light structure, there is indeed no a unified have a lot of experience engineers or project managers often completely understand, but we can not with some data light consideration and consider the judgment: 1, plant than weighing lifting weight: greater than 25 tons, can be considered a steel structure weight greater than or equal to 50KG / M2 per square metre with a traveling crane, can be considered as a heavy structure. 3, the main steel structure steel plate: greater than the same kind of 1 MM, light steel structure used.
In addition, there are some reference values: such as cost per square metre, maximum component weight, maximum span, structural form, eaves height, etc. The above can provide empirical data when judging whether the plant is heavy or light steel, but of course many buildings are now light and heavy steel. But there are some that we can say with some certainty are heavy steel: such as: petrochemical plant facilities, power plant plants, large-span stadiums, exhibition centres, high-rise or super high-rise steel structures. In fact, there is no such thing as heavy steel in national codes and technical documents. To distinguish light steel villas, it is perhaps more appropriate to call general steel structures “plain steel”.
Because of the wide range of ordinary steel structures, can include a variety of steel structures, regardless of load size, and even including many elements of light steel structures, light housing steel structure technical regulations only for its “light” characteristics and provide some more specific content, and the scope is limited to single-storey portal frame. This shows that the difference between light steel and heavy steel is not in the lightness of the structure itself, but in the lightness of the envelope material it is subjected to, and the structural design concept is still the same.
There is no unified standard for judging the structure as heavy steel and light steel structure, but it can be comprehensively considered and judged based on some data:
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 a number of reference values: e.g. cost per square metre, maximum component weight, maximum span, structural form and eaves height.
The above can provide empirical data when determining whether a plant is heavy or light steel. Many buildings are, of course, both light and heavy steel.
But some we can say with certainty are heavy steel: for example, petrochemical plant facilities, power plants, large-span stadiums, exhibition centres, high-rise or super high-rise steel structures.
In fact, there is no “heavy steel” in the national codes and technical documents. In order to distinguish steel structures for light houses, it may be more appropriate to refer to general steel structures as “ordinary steel”.
Because it is very wide, can include steel structure, not divided into a variety of ordinary content, even a lot of light steel structure, “light house steel technical specifications” only provides some more specific. “The characteristics of the single-storey portal rigid frame can be chosen arbitrarily.
Light steel is also a vague term that can be understood in two ways. One is J a round steel refers to the design code of the structure (GB 17-88) chapter 11 of the “light steel and small angle steel structure”, is light steel and small angle steel structure L45 * 4 and L56 * 36 * 4 made of small round steel and angle steel similar structure of light steel.
It can be seen that light and heavy does not lie in the weight of the structure itself, but in the weight of the steel material, but in the concept of the structural design.
Taking the steel structure plant as an example, the lifting adopts the principle of “first in the middle and then outside, first column and then beam, first down and then up”, first forming a stable frame system in the middle of the plant, then pushing towards the two ends and installing the remaining steel columns and beams symmetrically, in the following order.
Footing bolt recheck → unloading of steel components → component movement check → direct lifting in place by truck-mounted crane → temporary tightening of footing bolts → temporary tensioning of rope wind to stabilise → adjustment of steel column axis position and verticality → tightening of steel column bolts and column base pressure plate welding → installation of next steel column → installation of ties between steel columns → formation of first stable lattice system → assembly of steel roof frame as a whole on the ground and lifting in place by two machines to form the first steel roof frame → symmetrical installation of columns and roof frame systems on both sides → …… → analogy → completion of steel structure installation and structural acceptance.
With the main function of building materials, the traditional structure has a high building force, is stronger than the brick and mortar process, has better seismic performance, has better wind resistance, windproof, waterproof, fireproof effect.
Steel has good seismic performance and can prolong the consumption of energy brought about by earthquakes, so it has better seismic performance and structural safety to ensure the safety of the dwelling.
All components can be installed immediately on site at any time, extending the construction period indefinitely. A 6,000 m² building can be used up in 40 days.
Universal computerised steel buildings, which can be serviced by universal computers, are easy to use and designed.
Steel buildings have clean, smooth lines and a modern feel.
Coloured walls are available in a wide range of colours and the walls can also be made of other materials, making them more flexible.
All houses have a certain lifespan. The raw materials removed from brick and mortar houses generally cannot be reused and can produce a lot of waste that pollutes the environment.
The steel of a steel structure house can be 100% recycled and recyclable. The construction and demolition process is less polluting to the environment and meets the requirements of residential industrialisation and sustainable development
1、The cost is relatively higher than traditional brick and steel.
2, steel housing with its unique steel frame, walls, roof and other materials, as well as standardised, stereotyped internal layout and supporting facilities, it is difficult to adapt to the habit of “arbitrary treatment” of housing.
3. Corrosion of steel: aluminised and galvanised steel must be used to prevent corrosion to the maximum extent possible, and the main steel structure can reach 50 years.
4. There are many requirements for new materials. Steel residential structure is equipped with insulation and other materials, and new lightweight building materials will be widely used.