Prefabricated buildings refer to completing the required modular construction in the factory and assembling structures on site, which are suitable…
The type of steel building structures is the portal rigid steel frame, the frame structure, the truss structure, and the grid structure. Understanding the advantages and disadvantages of different structural systems is essential to design your project correctly. The forms of stress are also different.
Features and applications of the standard type of steel building structures:
- The Portal frame structure is a form of a closed structural system. It has a simple force, clear force transmission path, and fast construction speed. Introducing a portal frame structure strengthens the bonding properties of walls and generates more flexible space layouts, thus providing more possibilities for engineering creativity.
- Steel building frame structures are used to construct high-rise and super high-rise buildings, multi-story buildings, and commercial office buildings with the flexibility of their structure. A steel building frame can be adjusted to suit your needs.
- The advantage of Steel Truss Structure is that small cross-section rods can be used to form larger cross-section components, which are often used in industrial and civil buildings such as roofs, bridges, TV towers, mast towers, marine oil production platforms, tower corridors, etc., with large spans or heights In the building.
- The Steel Grid Structure is a high-order, statically indeterminate space structure composed of many rods according to certain rules. The space is small in force, light in weight, rigid, and has good seismic resistance. It can be used as a gymnasium, exhibition hall, rain roof, and canopies and hangars.
1. Portal Frame Steel Building Structures
The portal steel frame comprises hot-rolled or welded section steel, cold-formed C/Z steel, and steel pipe as the main force-bearing components and adopts a light roof and wall structure. The Portal frame is the most common form of the light steel structure.
The rigid portal frame is a structure with rigidly connected beams and columns. It has the characteristics of a simple structure, lightweight, reasonable stress, and simple construction. Therefore, it is widely used in industrial, commercial, agricultural, and Institutional Buildings.
2. Steel Building Frame Structures
The steel frame structure comprises beams and columns that can withstand vertical and horizontal loads. Columns, beams, bracing, and other members are rigidly or hingedly connected to form a flexible layout and create a larger space. It is widely used in multi-story, high-rise, super high-rise buildings, commercial office buildings, conference centers, and other buildings.
3. Steel Truss Structure
The steel truss structure comprises several rods hinged at both ends of each rod. It can be divided into a plane truss and a space truss. According to the parts section, it can be divided into tube truss and angle steel truss. The truss generally comprises the upper chord, lower chord, vertical rod, diagonal web, and inter-truss support. The steel used in trusses is less than that of solid web beams, the structural weight is lighter, and the rigidity is greater.
The advantage of the steel truss is that it is used to form more significant members with smaller cross-sections. It is often used in roofs, bridges, TV towers, mast towers, marine oil platforms, and tower corridors of industrial and civil buildings.
4. Steel Grid Structure
According to a specific rule, the grid structure comprises many rods with small space stress, lightweight, high rigidity, and excellent seismic resistance. It is used as a gymnasium, exhibition hall, and aircraft hangar.
The composition of the portal frame steel workshop system:
Steel structure workshops are divided into light steel workshops and heavy steel workshops. The workshop’s structural system is mainly composed of steel columns, wind columns, parapet columns, roof steel beams, crane beams, inter-column bracing, horizontal roof bracing, wall girt, roof purlins, tie bar, and other components. The primary structure is the portal steel frame, which can be single-span, multi-span, or multi-story, with an economic span of about 24-30m.
Common nodes of portal frame
The portal steel frame’s particular nodes include the column foot node, beam, column-to-beam node, roof beam node, column and roof bracing, tie beam connection node, and gutter bracket.
The composition of the steel frame structure
For the steel frame structure, with the increase of the number of layers and height and bearing a large vertical load, the lateral resistance (wind load, earthquake action, etc.) requirements become the primary bearing characteristics of the frame.
The steel frame structure system is generally divided into frame structure, frame bracing structure, frame shear wall structure, and frame tube structure.
Frame structure: The frame comprises columns and beams bearing vertical and lateral forces. Steel columns generally use H-shaped steel, box-shaped steel columns, or steel tube concrete columns.
Frame bracing structure: The frame comprises columns and beams, and bracings are provided between the columns to resist lateral forces.
Frame shear wall structure: similar to the frame bracing structure, except that the bracing is replaced with a shear wall to resist lateral forces.
The shear wall is generally a concrete slab, steel plate, or a steel-concrete composite structure with better lateral stiffness than bracing and is more flexible in layout and suitable for higher building structures.
Frame tube structure: The structure generally comprises a reinforced concrete core tube and an outer ring steel frame.
The system form uses pure steel frames in the horizontal direction and arranges an appropriate number of vertical inter-column bracing in the longitudinal direction to strengthen the longitudinal rigidity, reduce the amount of steel used in the frame, and form a larger space.
Common nodes of steel frame structure
Common nodes of steel frame structure include the column foot node, beam-to-column node, beam-to-beam node, the node of column joint, bracing node, beam-on-column node, etc.
The composition of the steel truss structure
The truss is a structure formed by a plurality of rods hinged connected at each rod’s end and divided into a plane truss and a space truss. The sectional form of the parts includes tube truss, H-shaped steel truss, box-shaped truss, angle steel truss, etc. The truss generally comprises upper chords, lower chords, vertical rods, web rob, and bracing between trusses. The steel used for the truss is less than that of the H beam, the structure has a lighter weight, and the rigidity is greater. It is widely used in high-rise buildings, large-span structures, and bridges.
The composition of the Steel grid structure
The grid is a spatial structure that connects multiple rods with nodes in a specific grid form. There are many types of grids, which are classified according to different standards. The different composition methods are divided into cross-truss system grids, triangular cone system grids, quadrangular cone system grids, and hexagonal cone system grids. The flat grid mainly comprises chords, diagonal webs, intermediate nodes, support nodes, etc.
Steel Building Structures VS Reinforced Concrete
The steel structure building uses advanced design, processing technology, and large-scale production methods to reduce costs significantly. Simultaneously, the simple and rapid installation saves many construction costs and enables enterprises or developers to put it into production more quickly.
Traditional reinforced concrete buildings have a high civil construction cost and long construction periods. The cost is susceptible to unpredictable factors, such as natural disasters, construction in winter and rainy seasons, and rising material prices.
The steel structure building can be delivered and installed quickly. The installation is expected to be completed within four or five months after the contract is signed, and it is not affected by winter construction.
The construction speed of traditional reinforced concrete structures is slow, and the construction period can reach 8-10 months or longer.
The weight of the steel structure building is usually only equivalent to 1/6 of its design bearing capacity. The weight of components is much lighter than that of reinforced concrete components.
In traditional reinforced concrete buildings, the structure’s weight is often equal to its designed load-bearing capacity, and the prefabricated components are heavy, requiring high-lifting equipment.
Due to the light weight of the steel structure building, the reaction force at the bottom of the column is small, saving many foundation treatment costs.
Traditional reinforced concrete buildings have complicated foundation treatment due to their complex self-weight. Over half of the total structure cost will be used for the foundation in poor soil quality.
Steel structure buildings have large deformations before destruction, which is easy to detect and avoid. Simultaneously, the steel structure has excellent seismic performance due to the lightweight and the joints’ mechanical properties.
Traditional reinforced concrete buildings are based on the material properties of concrete. Compared with light steel structures, reinforced concrete buildings are more prone to brittle failure, and their seismic performance is significantly lower than steel structure buildings.
Large space and floor plan
The interior space of the steel structure building is spacious, with a span of up to 60m. It can be expanded and rebuilt relatively easily, and various industrial pipelines can be flexibly laid out.
The span of traditional reinforced concrete buildings is limited, and prestressing technology must be used to achieve a span of more than 15m. The internal space layout is limited, and there are many columns and large space waste. After its completion, it is more difficult to persuade its structure. The structural design is more complicated to cooperate with other professions.
Bolts can connect the steel structure building, and they can be easily disassembled, transferred, and assembled easily without much expense, and has strong mobility. There is basically no possibility of movement in traditional reinforced concrete buildings.