Steel beams, columns, and braces are needed in residential construction when wood members cannot support high loads and/or constraining geometry. For example, steel beams are often required to achieve a long, clear-spanning open living space or garage because a wood beam might bend or break. Steel might also be necessary when there is insufficient space to install sufficient wood framing—large window or door openings sometimes require steel frames instead of wood.
While there are numerous steel shapes that are available, we most often specify Wide Flange steel (W-beam) sections or Hollow Structural Steel (HSS) sections for residential construction.
Wide Flange (W-Beam):
This commonly used steel shape is often referred to as an I-beam, as the section profile of these beams looks like the letter I. This steel shape can be used in most loading scenarios (beam, column, brace) and can be easily installed for residential contractors and framers without field welding. W-beams are hot rolled from many different ASTM materials; A992 and A36 are the most common materials.
- Commonly available in an extensive range of sizes and strengths.
- Good connection compatibility with other steel or wood members. Bolted connections can offten be used instead of welded connections.
- Very efficient in resisting gravity loads (flexural and compression).
- Not as efficient as HSS dimensionally (i.e. a smaller, lighter HSS can often support the same load as a larger, heavier W-beam).
- Inefficient in resisting torsional loads (rotation) and weak axis loads
Hollow Structural Section (HSS):
HSS tubes come in square, rectangular, and round sections. HSS tubes can also be used in most loading scenarios (beam, column, brace) and usually require field welding. HSS tubes are cold-formed steel shapes made from ASTM A500 steel.
- Commonly available in a large range of sizes and strengths, though not as available as W-beams.
- More weather resistant than other steel materials
- Very efficient in resisting several different loading conditions
- More efficient than W-Beams dimensionally except in flexural applications (i.e., a smaller, lighter HSS can often support the same load as a larger, heavier W-beam). Less weight often means less money!
- Connections are often more challenging to install for residential contractors as they are often welded connections.
- Not as efficient in flexural applications as W-Beams.
As structural engineers, we consider several components when designing steel members for each situation:
- The efficiency and load resistance of a steel shape in that situation
- The cost and availability of a steel shape
- Connection design and ease of installation.
A contractor, framer, or steel installer might all have a different preference of which steel shape to use in different scenarios. We often ask the appropriate parties about their preferred connection and installation method before designing the steel.
If you have questions about steel design in residential construction, contact Team Engineering, we will be glad to help!