Engineering overview of steel structure design

I. Concept of steel structure
Steel structure is a load-bearing structure made of steel plates and steel profiles processed into various shapes of steel components, which are connected and fixed with each other through welding, bolts and rivets. It has the advantages of light weight, high strength, short cycle of production and equipment, strong reliability, good anti-seismic function and so on, so it is widely used in construction projects.
Steel structure is widely used in the construction of national economy. In the house building, there are a large number of steel factory buildings, high-rise steel structures, large-span steel net frames, suspension structures, etc. In the highway and railway building, there are various ways of steel bridges, such as plate girder bridges, truss bridges, arch bridges, suspension bridges, diagonal tensile bridges and so on.
The composition of steel structure should satisfy the requirements of structural application function, and the structure should form a few invariable space whole, so as to effectively and economically bear the load.
Characteristics of steel structure
Compared with other structures, steel structure has the following characteristics:
(i) Light weight of steel structure
Although the density of steel structure is larger, but compared with other building materials, its strength is much higher, so when the load and conditions of bearing together, steel structure is lighter than other types of structures. The primary performance:
(1) Constant load is light due to the selection of lightweight enclosure structure, constant load and seismic effect is greatly reduced, the foundation is simple, low requirements for the foundation, seismic function has been strengthened.
(2) Small cross-section of members Due to the selection of new design theory, high-strength steel and new structural system, the cross-section of load-bearing members is small and the amount of steel used is low.
The steel structure project compares with reinforced concrete deep foundation, fat column, fat beam and heavy cover structure, and the word ‘light’ is more outstanding. Regarding industrial and civil buildings without crane beams, the steel consumption of light steel structure is generally 20~50kg/㎡, therefore, it is more suitable for some areas with soft foundation.
(ii) steel plasticity and good resistance
In terms of building components, the requirements of components in the force damage should be plastic damage, avoid brittle damage, or known as sudden damage. And steel because of its extension function is good, it is clear that its plasticity is excellent, generally not due to occasional overload or part of the overload and suddenly damaged. Because of the good resistance of steel, it makes the steel structure to move in general not all medical, it can be said that, the plasticity and the brake of the steel property for the steel structure project safety and reliability of the supply of the quality assurance.
(III) Steel structure is easy to make, and the equipment construction cycle is short.
Composed of various types of steel, C-type steel, angle steel or round steel and other profiles, the production of a large number of steel structure components are made in a specialised production plant, with reliable quality and high accuracy. The construction period of steel structure is only 1/3～14 of reinforced concrete project when comparing with reinforced concrete project of equal area. Therefore, short construction period of steel structure project is one of its most competitive features. Moreover, the connection of steel structure components is mostly chosen to be welded and bolted, so it has the feature of convenient construction.
(IV) Large span, small area occupied by structure
As steel has unique physical characteristics, it can be used to make large-span and large-space buildings, and it can be spaced out sensitively. Due to the large-span structure reduces the occupied area of steel columns, beams, walls, intervals, etc., which is equal to the increase of unit use area. The occupied area of steel structure can be reduced by about 25 per cent compared with the occupied area of similar reinforced concrete structure. This actually increases the use value of the building and the economic benefits of investors.
(E) In line with the national environmental protection concept of ‘green, environmental protection and energy saving’.
The use of steel structure project makes the wall enclosure material also be changed. As clay bricks are screened, it protects our limited land resources. The choice of steel structure also reduces the need for digging and burning cement, which is conducive to the protection of the ecological environment. In the equipment construction site, due to the selection of the whole assembly connection, greatly reduced the workload of concrete mixing, masonry mortar mixing, concrete protection and other operations, limiting the dust pollution, reducing construction waste, and reducing the construction noise. In terms of energy saving, more than 98 per cent of the steel structure components can be recycled, which saves both materials and power and is in line with the principles of green, environmental protection and sustainable development.