Introduction
- Openings in masonry walls are spanned by horizontal members known as lintels. The lintels may be constructed
of:
- Precast or cast-in-placements.
- Structural steel
- Reinforced concrete masonry.
- Concrete masonry is preferred because it does not require special lift equipment and surface texture is not interrupted.
- Lintels are primarily and conservatively designed as simply supported beams.
- If arching action is permitted, the lintel design loads can be much smaller.
- This occurs for lintels with considerable wall above.
- The wall over the lintel will tend to create an arch over the opening, leaving only the area under the arch to be carried by the lintel beam.
- Valid for running bond, but not stack bond.
- Loads will "arch" around the load triangle, as shown below.
- The wall above could be simply modeled as a 3-pin arch.
- If there is not enough wall on either side of the opening to resist the arch thrust, or if a
45° triangle cannot be fully drawn in above the opening, then you cannot count on
arching action to distribute loads around opening.
- This occurs for lintels with considerable wall above.
