Pre-Engineered Metal Buildings 101

Avoid being unaware of a number of all necessary aspects that could lead to a direct downfall of your building project. If you’re in the market for a pre-engineered metal building, you may need help determining the best metal building system for your home or business needs. Here is some useful information on the general basics of metal building systems.

Several years ago, Metal Building Systems became commonly referred to as “Pre-engineered Buildings”. The term is still popular in the building trades today, despite efforts by MBMA members to change the culture. In general, a Metal Building System is defined by MBMA as “a complete integrated set of mutually dependent components and assemblies that form a building. It includes the primary and secondary framing, covering, and accessories, all of which are manufactured to authorize inspection on site prior to assembly or erection”. To be more straightforward, it is a steel frame building that typically consists of the following metal components:

  • Columns
  • Connections
  • Endwall Beams and Columns
  • Flange Braces
  • Frames (including side wall columns)
  • Girts
  • Longitudinal Bracing
  • Purlins
  • Roof Sheeting
  • Screws and Bolts
  • Wall Sheeting
  • Other non-structural parts

When all of these components are assembled, a complete structure is created in the form of a shell. On average, all components are designed, fabricated, and furnished by a single manufacturer based on individual requirements. All parts are directly delivered to the job site and assembled by a structural steel erector or general contractor. Production normally uses field-bolted connections with little or no field welding. Meanwhile, primary components, such as columns, beams, and girders, are typically fabricated from plates, are shop welded and optimized for the specified loading conditions. To conserve material in areas of low stress, webs of beams and columns are normally tapered. While Metal Building Systems with tapered rigid frames are the most common, other types of framing are also in common use: single span self-framing (no frame), multiplespan beam and column frames, trussed column and girders, trussed rigid frames, continuous beam frames, columns with tapered girders, etc.

The reference of Metal Building Systems to Pre-engineered Metal Building was an appropriate name because it described the procurement process in place at that time. In the past, building manufacturers would hired structural engineers to design a series of standard building modules for different wind loading. These modules differ in areas, such as: eave height, building width, and roof slope; and could then be joined to create buildings of practically any length. A purchaser would customarily review the company’s catalog, select a building with a footprint and interior height that most closely matched the requirements, and place the order with the supplier. The manufacturer would then engineer the parts based on the standard design drawings on file and directly ship the building to the owner’s site. The erection of the building would be finalized by a general contractor or by an erector that worked with or for the supplier. This past approach is quite different from the modern process. Today, most manufacturers use proprietary computer programs for design and provide a custom designed order for an entire building (frame, wall, and roof covering) or parts (frame and roof). To provide a complete facility, parts can also be combined with other building materials (masonry, precast concrete, light gauge steel framing and siding, windows, overhead doors, etc.).

The principal advantages to using a Metal Building System type structure includes: low cost and speed of fabrication/erection. Manufacturers that specialize in this work have developed design and fabrication techniques that make them very competitive. There has been the perception that these buildings are inferior to other custom designed structures. This is primarily derived from early industry reliance on a separate building code (MBMA Low Rise Building Systems Manual); which, at one time, encouraged the use of wind and live load pressures that were inferior to those traditionally used. However, recent changes in both the MBMA design guidelines and the traditional codes have brought the two closer together with fewer differences.