Masonry Lintel Arching Load (Triangular Load Over an Opening)
The triangular dead load a lintel carries within a 45-degree triangle (height span/2) when the wall above >= span/2 +...
Example
You enter
- Opening (clear) span (ft) 6
- Wall weight above (psf) 60
- Height of wall above opening (ft) 5
You get
- Lintel dead load 540 lb (arching, triangular)
- Equivalent UDL (for moment) 120 lb/ft
Checked against published worked examples from: Concrete Masonry & Hardscapes Association (formerly NCMA).
Details, formula, and sources
ScopeThe triangular dead load a lintel carries within a 45-degree triangle (height span/2) when the wall above >= span/2 + 8 in (NCMA TEK 17-1), else the full rectangle. A 6 ft opening, 60 psf, 5 ft above -> 540 lb, a moment-equivalent 120 lb/ft; only 2 ft above -> the full 720 lb (also 120 lb/ft, uniform). Dead load only; the engineer of record governs.
Formula or tabletri_h = span/2; arching when wall_above >= tri_h + 8 in: W = 0.5 x span x tri_h x wall_psf and the moment-equivalent UDL = 4 W / (3 x span); otherwise W = span x wall_above x wall_psf (full rectangle) and UDL = W/span.
Source and editionThe masonry arching-action lintel-load method (TMS 402 commentary / masonry design references), by name.
Free accessThe 45-degree arching triangle for masonry lintel loads is a standard masonry-design method (TMS 402 commentary / masonry design references). The engineer of record governs.
What governsEstimate. AHJ and licensed professional govern.
API field namesspan_ft, wall_psf, wall_h_above, W_lb, w_udl_plf
- Arching triangle 45-degree triangle, height span/2; arches only when wall above >= span/2 + 8 in (TEK 17-1: 8 in of wall above the apex)masonry design method
- No arching case insufficient wall above -> the full rectangle span x height x psf (more load)masonry design method
- Dead load only add floor/roof/superimposed loads separately; confirm bond and no control jointscope of this tile