A reinforced masonry lintel designed to CSA S304 over a 2.1 m garage door opening needs both its flexural and shear checks run explicitly, since at this span, unlike the shorter window-opening lintel examples covered elsewhere in this series, shear capacity ends up mattering nearly as much as bending.
Every check above runs automatically inside the Structyze Masonry Lintel module — this particular module is part of the full desktop catalogue rather than the free browser trial, since the trial only carries a curated flagship set. You can still try the free trial modules right now to see the same calculation style in action on RCC Beam, Column, Slab and a handful of others.
The Example We'll Use
- Opening span: 2.1 m, lintel bearing 200 mm each side (effective span 2.3 m)
- Lintel: 2-course reinforced bond beam, 1-15M bar bottom reinforcement
- f'm: 10 MPa, f_y: 400 MPa
- Factored design load (no arching credit, insufficient masonry height above a garage door opening): distributed load from wall and floor above giving M_f = 9.8 kN·m, V_f = 17.0 kN
Working Through It
Factored moment resistance with the 15M bottom bar, using CSA S304's strength design flexural provisions: M_r = 13.2 kN·m. Utilization for bending: 9.8 / 13.2 = 0.74.
Factored shear resistance, combining the masonry's own contribution (based on net mortared area and f'm) with no additional shear reinforcement provided in this lintel: V_r = 19.5 kN. Utilization for shear: 17.0 / 19.5 = 0.87.
Shear, not bending, is the tighter of the two checks here — a direct consequence of this lintel's longer span and the absence of arching relief, concentrating more load onto the member than the shorter, arching-eligible lintel examples discussed elsewhere in this series.
What Governs, and Why
Shear governs at utilization 0.87, narrowly ahead of bending at 0.74 — an outcome specific to this lintel's longer effective span and the lack of arching credit, illustrating that longer-span lintels without arching relief can shift the governing check from bending (the more commonly expected governing mode for a simply supported member) toward shear.
Where Structyze Takes Over
Every check above runs automatically inside the Structyze Masonry Lintel module — this particular module is part of the full desktop catalogue rather than the free browser trial, since the trial only carries a curated flagship set. You can still try the free trial modules right now to see the same calculation style in action on RCC Beam, Column, Slab and a handful of others.
For Masonry Lintel and the rest of the full catalogue — 80+ components across RCC, Steel, Composite, Timber, Masonry and more, across 20+ design codes — buy the full Structyze desktop app or see everything it does on the Software page.
Quick FAQ
Can shear reinforcement be added to a masonry lintel if the masonry's own shear contribution isn't enough?
Yes — vertical stirrup-type reinforcement can be incorporated into a reinforced masonry lintel's grouted cores to supplement the masonry's shear contribution, similar in principle to stirrups in an RCC beam, when the unreinforced shear capacity alone isn't adequate.
Does a longer lintel span always shift the governing check toward shear?
Not automatically, but longer spans without arching relief do tend to increase both demands together while shear capacity (tied to the section's fixed cross-sectional area) doesn't grow proportionally with span the way bending demand does, which is the dynamic that pushed this specific lintel's governing check toward shear.
Final Thoughts
A longer-span lintel without the benefit of arching relief doesn't fail safely in the direction most designers instinctively check first — this example's shear check, not its bending check, turned out to be the tighter margin. That's why both need to be run explicitly rather than assuming bending always governs a simply supported member.