Comparison of Prefab Steel Structure and Concrete Structure

1 .From the design point of view


1.1Common ground

1) The principle of calculation

Regardless of the concrete structure or prefab steel structure are based on "plate →beam →column →base" such transmission force transmission force. Regardless of the difference in the shape of the two structures, the calculation principle is the same from the stress. Need to use the traditional mechanics and mathematical formula for analysis.


2)Construction and conceptual design

A good building is determined by many factors, and the decisive stage of the building is in the design stage, and in the design phase of the construction engineers will always intentionally or unintentionally put their own design ideas reflected in their own works, The level of the designer level is often determined by the depth of his concept design, which places should be noted that what places can be relaxed requirements, the same design, which is the most efficient and most economical and most cost-effective, these are steel And the concrete structure of the common need to pay attention.


3) Earthquake measures

Prefab steel structure than the concrete structure "soft" some, but both to satisfy of the seismic design of the "three-level quasi-two-stage" design should have a multi-channel seismic fortification system to avoid the loss of seismic capacity or loss of bearing capacity due to the failure of part of the structure or component, and the necessary bearing capacity The ability to deform and energy consumption. Should be taken into account the structural system of the actual stiffness and strength, to avoid local weakening or mutation and the formation of weak parts, to avoid excessive stress concentration or plastic deformation concentrated on the possible weaknesses and conversion layer should take the necessary structural measures.


1.2 Different points

1) Architecture and Structural Design

All the buildings are ultimately achieved through the material, and the characteristics of the material and all the time the impact of the various properties of the building, which in turn will restrict the designers of the architectural work of the various functions of the requirements.

Prefab steel structure is mainly made of steel components connected, small weight, ductility is good, but at the same time poor integrity, poor fire resistance, susceptible to external corrosion, poor insulation.

The concrete structure is made up of reinforced concrete and concrete, which is large, the stiffness is large, and the earthquake damage is obvious, but the integrity is better, it is not easy to be eroded by the outside.

Material determines the nature of the prefab steel structure and the concrete structure is different, resulting in their various performance advantages and disadvantages. So the design must be fully aware of this, learn from each other, give full play to their respective advantages, so that the design is economical and reasonable.


2) The mode of force analysis

The main structure of the prefab steel structure is the steel component, only one material, so the force transfer is simple, clear way, easy to establish and the actual force close to the calculation model.

Concrete structure is different, because the concrete structure by the role of reinforced concrete and concrete, so the force transmission is more complex, the way is not very clear, even if the artificial use of this or that assumptions to establish the calculation model, the final calculation results and the actual The situation is still a certain difference.

If the concrete structure is composed of steel and concrete together, the "composite", the prefab steel structure is connected by a variety of steel components from the "combination." In addition, the concrete structure of the number of statically longer than the prefab steel structure to be more, the joints at the joint stiffness than the prefab steel structure.


3) The composition of the structural system

Ordinary concrete structure is mostly composed of "beam, plate, column", because the concrete material weight is relatively large determines the concrete structure does not apply to the larger span of the building.

The form of the structural system of the prefab steel structure is not as single as the concrete structure, and its form has a variety of "beams, plates and columns", and "roof trusses, columns", "lattices, columns", " "And so on, because the prefab steel structure of light weight, and the strength, it can be widely in a variety of large-span structure, especially in a variety of span requirements of relatively large factories, gymnasiums, exhibition halls, cafeteria and so on.


4) Structural measures

In the concrete structure in order to achieve the purpose of strengthening the structure, usually by increasing the reinforcement area, cross-sectional size, or concrete label and increase the ring beam, structural columns, etc. to local strengthening the resistance of components or floors.

In the prefab steel structure in order to strengthen the interconnection between the components of the performance and overall or local stability, to prevent the local loss caused by the destruction of the entire structural system. (Such as column support, roof truss support, roof truss support), increase the stiffener (such as the column stiffener, H-beam between the upper and lower flange between the stiffener, H-shaped steel column between the upper and lower flange (Such as Tan between the roof and roof truss), in short, because the light prefab steel structure of the bar more and the form of complex and diverse, so the structure than the concrete structure requirements more stringent, while the structure The way and the measures between the two are also very different.


5) The result of damage

According to a large number of data show that the concrete structure of the earthquake damage mostly cracks, concrete crushed, steel yield, local collapse or destruction, and the whole building collapse situation is rare.

Prefab steel structure under the action of seismic force due to the ductility of steel is better, the component part of the brittle failure will not occur, there are distortions, instability, deformation of the situation is more, and in each component connected to each other, reasonable choice of energy consumption is Critical. While strengthening the local stability, but also pay attention to strengthen the overall stability, even if the bar in the case of force analysis will not be unstable, the overall still there is the possibility of instability, so the seismic check for the overall stability Sex must pay special attention. This is very different from the concrete structure, the concrete structure is relatively good, as long as the components do not damage the general will not appear the overall instability of the situation.


6) Building requirements

Although the concrete structure from the major, cannot be too high, but the integrity, airtight, fire than prefab steel structure is better. The prefab steel structure in the fire, rain, heat insulation, insulation and other requirements than the concrete structure is even more important, while the prefab steel structure is easy to be corrosion, but also regular anti-corrosion treatment to ensure that the steel life. These jobs will be a bit cumbersome. With the emergence of high-level, the challenge of building height limits the structural engineers to have to choose the prefab steel structure as the main structure, whether it is the US World Trade Center, Hong Kong Bank of China Building, Shanghai Oriental Pearl, Jin Mao Tower, or in the Arab Union Emirates Dubai, the world's first high 828m Dubai Tower, are everywhere visible steel figure.