Industrial frames (industrial shed) are used as one or more spans, and typically one floor with sloping roof to cover large spans in industrial factories, agriculture, warehouses, repair shops, etc. In the not so far years, truss structures were used to cover large spans in the buildings.
Today, however, the use of frames (industrial shed) with variable cross section and moment joints in the manufacture of industrial metal structures is very common. The use of variable-gradient members in sloping industrial frames allows that places with a greater flexural anchor to have more inertia moments and therefore a larger cross-sectional basis. The cross-section of industrial frames is generally in the form of “I”, in which the dimensions of the wing along a member is fixed but of the height of the web are considered, depending on the size of the variable member’s bending anchor.
Industrial frames with variable section are also called shed that in our country there are several factories that calculate, design and execute industrial frames in the form of shed for various spans. Due to the progress of the welding technology, most joints in the making shed factories are carried out in the form of weld, and mainly the assembly and execution of the industrial shed in the used location by screw joints are considered.
Determinant factors in the weight of industrial structures
The area in order to build the industrial shed is due to the rate of the wind speed, as well as the maximum amount of snowfall, the span of the hall, the height of the columns
Economizing any order is actually, knowing the actual size of the mentioned dimensions and predicting requirements. Obviously, the best computations without considering the quality of welding, the use of bolts and nuts, and other standard joints, de-rusting and scientific coloring, or the proper application of the components, will be lacked the necessary strength and effectiveness. It needs to be explained that all manufactured parts of the company have been using a multi-year experience and constant monitoring, automatic submerged arc welding and the use of a fully standard material that can be seen at any time by the employer and has been approved by dozens of consulting firms and the monitoring device.
Basic information required for the design of industrial structures
- The Span
- The length
- The Height
- The Slope
- Information about the location of the installation of structure
- Load on structures such as overhead cranes
Sloped Frame of the Industrial Shed
The steel frame system plays a main role in bearing various live loads, snow, load, earthquakes and crane loads in industrial buildings. The steel frame system usually consists of members with variable cross-section and rigid-connections (rigid connection). These members are jointly under the influence of the by axial force, shear force and bending moments, which are:
- Industrial shed normal brace
- Industrial shed ceiling brace
- Longitudinal compressive elements of the ceiling of the industrial shed
- The layers of the industrial shed
Loads on the roof of industrial buildings is tolerated by layers and shifted to the steep main frames. Layers are designed and implemented in the form of beams with simple or longitudinal spans equal to the distance of the frames throughout the hall or as continuous beams. The layers section is “I” shaped. It is recommended that the maximum allowed displacement of the layers due to the sum of dead loads and snow superimposed load is less than 1/200 of the length of the crater.
To prevent lateral torsional buckling of the main frame beams, they should be properly arranged to hold their compression flange at necessary intervals and alongside the side of the frame plate.
Anchor rod of the industrial shed
Anchor rod of the industrial shed connects the width of the layers at certain intervals. The anchor rods, which are perpendicular along the layers in the sloping frame roof, play three important tasks:
- They tolerate thrusting along the inclined plane
- Layers as lateral bracing prevent from the lateral torsional buckling of the compression flange.
- The flexural span around the weak axis reduces the layer’s profile.
Industrial shed building because of its largely industrial application in terms of design is different with other structures, especially the frames are completely different in these types of structures and have slopes, and the spans are also larger than other structures. Due to the large dimensions of the beams and columns, it is not possible to use the profiles existing in the market for the construction of this structure and they should be constructed, which is called the plate girder.
The design of industrial shed
The designing of industrial shed is specialized and highly accurate, important factors are involved in design, which can inevitably impose a significant cost on the constructor, which question the economic cost and may also reverse the opposite result and undermine the strength and stability of the structure. . For the design of industrial sheds, software called Soole Pardaz (SAP) is used. Using this program, a bridge crane, bearing cranes and foundations can be designed. The following information is desirable to design an industrial shed:
- Snow load and wind force on the industrial shed
- The side height elevation of the industrial shed
- The desired slope for the roof and naturally calculation the height of the industrial shed crest
- The length of the industrial shed cross span
- The length of the longitudinal spans and the number of considered longitudinal frames of industrial shed
- Is the crane considered in the design of the industrial shed or not?
- The desired cover of the roof
By knowing the above information and the intended dimensions for the industrial shed, we attempt to design it, which will eventually become the working drawing and implementation of the structure, but the implementation of the structure of the industrial shed is seemingly easy but in the back is hard, and there are certain engineering teams that execute the industrial shed. Assembly, alignment and adjustment of the frames of the industrial shed are a very sensitive work, keep in mind that the sidewall braces are implemented quickly and at the same time because one of the weaknesses of the industrial shed structure is its weakness of stability against lateral forces, which is, of course, completely restrained by the side guards But its execution time is significantly important.
Cutting and drilling the industrial shed
Before making various components of the industrial shed, by using the build order plans (SHOP DRAWING) plate is cut by the guillotine (iron scissors) in the workshop, and then assembled and welded, the necessary drilling is done at this stage as well.
Confirmation and color of industrial shed
Before painting, parts are checked and approved by the engineers and sent to the sandblast if needed, and are ready to be painted after cleaning. At this stage, two or three layers of paint are applied to the columns and the girders and other metal components, in which the number of layers and type of paint are available in specifications and drawings.
Painting with brush is not allowed and should be painted with pistol.
Sandblast is said to be operational, during which the silica sand is sprayed with pressure on the piece to prepare the surface for painting, in addition to clean-up rustiness. Usually, all metal parts are sandblast before painting. An important point in Sandblast’s operation is that it should be avoid from exaggerated at this work, because it will cause erosion and thinning of metal layers.
Transportation and installation of industrial shed
After painting, the stage is transportation and installation of the industrial shed that the built parts are transported from the construction location (workshop) to the place of installation (the buyer’s land) and the installer’s unit for the installation of the industrial shed is dispatched to the site. The installation is carried out by heavy cranes. At this stage, it must pay attention that the frame must be installed completely, because due to the height of the columns, if the rafters are not installed and installing the columns individually and dropping out them, there is the possibility of a reversal of the column.
Computational loads of industrial shed
The loads loaded on an industrial building include the following, which should be calculated according to the recommendations of valid regulations and applied appropriately to the industrial frame. The dead load of the industrial shed includes the weight of the various parts of the frame, roof coverings, glass wool and chicken wire.
Snow load of the industrial shed
According to the geographical location and the location of the industrial frame, in terms of the amount of snowfall, wind and slope of the industrial roof, the loads from snow on the frame are determined and applied to the frame.
Wind load of the industrial shed
The load caused by the wind blows horizontally and sideways along the main axis of the industrial building.
Earthquake load of the industrial shed
The earthquake load should also be determined according to the proposed relationships of loading regulations and applied appropriately and horizontally on the industrial frame. The earthquake force is a function of the weight of the structure, the coefficient of frame loading of the structure and etc.
Crane load of the industrial shed
In some industrial buildings, cranes are installed to move heavy objects in the longitudinal and transverse directions of the hall. The main bridge and crane rails should be designed for the most critical type of loading.
Advantages of the industrial shed
- High flexibility
- Ability to avoid intrinsic imperfections
- Ability to design and implementation of large-scale structures
- High safety against environmental degradation factors
Ability to implement structures of various s