Engineering Tips: Understanding Lintels and When to Use Them
What are lintels and when should they be used?
A lintel is a structural member used to support loads across an opening, resisting forces in both the horizontal and vertical directions. While an I-shaped member may be sufficient for standard roof beams or wall spandrels, lintels are often specified as tube sections due to their ability to efficiently handle biaxial loading and torsional forces.
When do we typically see lintels being used?
Most standard walk doors and windows do not require a lintel, as the wall panel can typically support itself over smaller openings. Additionally, wall systems provided by others often include a built-in header, which eliminates the need for a separate lintel.
Common applications requiring lintels include:
- Large clear openings in a hardwall
- Storefront glazing (glass) located beneath a hardwall system
In these cases, the hardwall system above requires structural support. Lintels are provided to carry vertical loads and establish a stable working point for the installation and alignment of wall sections.
Information required for design:
- The weight of the wall system above the lintel
- Deflection criteria for the lintel, including both vertical and horizontal limits
- Any placement or geometric constraints (see below), including clearances, alignment, or coordination with adjacent systems.
Common lintel details
Tube sections are the preferred choice for lintels due to their strength in resisting vertical, horizontal, and torsional forces.
The most common detail consists of a tube with a shelf plate welded to the bottom. This configuration allows the tube to be recessed behind the wall plane, while still providing a functional working surface for construction.
An alternative detail is a flush-mounted tube, where the wall system bears directly on top of the lintel. This approach minimizes the overall footprint within the building envelope. However, there are several disadvantages to consider:
- The tube is located at the steel line and may be exposed to exterior conditions
- End connections to columns can conflict with the wall system layout
- The tube size is limited by wall depth, which may lead to feasibility challenges or increased cost
