Pre-engineered buildings are factory-built buildings of steel that are shipped to site and bolted together.
A portal frame building is a modern technology where the complete designing is done at the factory and the building components are brought to the site in a completely knock down condition and then fixed/jointed at the site and raised with the help of cranes.
Below, we will highlight the types of components used to build modern steel structures.
2. Primary Framing
Primary framing is comprised of fabricated columns and rafters; referred to as frame lines or main frames when bolted together. These are the heavy members in the superstructure that bear the major weight and applied loads. These components are the distinguishable elements that people can see, and know without a doubt, that they are looking at a metal building. At Novelty Steel, we use generally hot rolled sections for columns and rafters.
Figure 1 Primary Framing
Without the complete primary frame, steel buildings would not stand up to vertical or lateral loads over time. The following items, bolted or welded together, form the superstructure:
- Columns: The vertical supports. Columns can come shaped as tubes or with a cross-sectional shape of a capital H, I, L or U.
- Beams: The horizontal supports that rest atop the columns. Usually I or H-shaped with flanges perpendicular to the “web” or main plate.
- Rafters: Also beams, these horizontal members support the roof assembly.
- Trusses and Lattice Girders: Alternative support for the roof or upper floors, comprised of a latticework of bracing metal between top and bottom chords. While the chords bear compression and tension loads, the bracing resists shear forces.
- Girders: Horizontal beams that support floors.
3. Secondary Framing
Once the backbone of your framing has been determined, the next step is to plan the secondary framing. Providing the stabilizing members that prevent the main frame from twisting out of shape, secondary components can also contribute to the structural support and provide the means to attach wall, roof and interior elements. The secondary framing usually transfers loads to the main frame.
- Girts and purlins — Girts tend to be Z-shaped, providing support for wall panels while increasing the strength and stability of the primary framing. Purlins serve the same purpose, but are utilized in roof applications.
- Wall and Roof Braces: Bars, cables rods or strips that resist shearing and contribute more lateral stability.
- Eave Struts: The transition piece between the wall girts and roof purlins along the eave.
- Headers and Jambs: The framework for openings such as doors, windows and bays.
The primary and secondary framing components needed to complete your structure will be manufactured in a steel fabrication facility to ensure the highest levels of quality and consistency. Once these pieces arrive on your site, it is time to assemble them with the approved fasteners:
- Bolts (anchor bolts, U-bolts, and so on)
- Construction screws
- Weld studs
- Threaded studs
5. Building Envelope
Typically comprised of pre-coated, single-skin metal panels; however, sandwich panels are becoming more steel construction cladding systems. However, just as common, the materials used to enclose a metal building structure can vary from masonry to glass, wood siding to innovative architectural panels, and beyond. Chances are the brick façade you see on your favourite retail store is hiding a metal building beneath. In certain applications, the metal panels add structural integrity to the building system as a whole, and why the term metal building systems is commonly used. Single-skin panels and the metal components of insulated panels are cold-formed, just like the secondary framing.
Figure 2 : Building envelope components
Sheet steel runs through a progressive series of rollers that shapes the flat material into a specific cross-sectional profile that is strong and durable. After cutting to length, appropriately bundled and crated, the finished product is ready for delivery. While an economical option, the through-fastened metal panel remains a long-lasting, attractive and versatile product. Architectural metal panels offer concealed fastener options, with enough variety to likely satisfy all aesthetic demands.
Pre-engineered buildings are distinguished from other buildings by the design& build concept. This style of construction is ideally suited to industrial buildings and warehouses; it is cost effective, very fast to erect, and can also be dismantled and transferred to another location. These structures are sometimes referred as “metal boxes” since they are essentially rectangular boxes enclosed in a skin of corrugated metal sheeting.