After this chapter, you should be able to
- Distinguish flexural, arching and free-standing routes.
- Select defensible edge support conditions.
- Check panel ratios and opening effects.
- Calculate M_Ed, M_Rd and utilisation.
- Explain the selected coefficient and governing warning.
3.1 Purpose and design questionSource §3.1
A laterally loaded masonry panel is normally checked for wind pressure or suction. Its governing action is bending, so first identify the physical resistance mechanism, support condition and failure direction.
3.2 Lateral-load design routesSource §3.2
- Route A — Flexural strength
- Panel bends between support edges. Report M_Ed, M_Rd and utilisation.
- Route B — Arching action
- Use only when supports can resist arch thrust and detailing permits compression arching.
- Route C — Free-standing wall
- Cantilever-type boundary wall without top or side restraint; check base moment and stability.
3.3 One-way and two-way panel behaviourSource §3.3
A long narrow panel commonly spans in one direction. A panel restrained on several edges can develop two-way bending and requires bending-moment coefficients selected for the actual supports and aspect ratio.
α₂ is the bending-moment coefficient, W_Ed is design lateral pressure, l is the relevant span and μ is the orthogonal strength ratio.
3.4 Support conditions and edge restraintSource §3.4
- Free edge
- No lateral restraint.
- Simply supported edge
- Transfers lateral reaction but not a design moment.
- Continuous edge
- Transfers restraint only when construction details justify the assumed continuity.
3.5 Serviceability size limitsSource §3.5
Check panel proportions before resistance. These serviceability-style checks help control excessive deflection, cracking, creep, shrinkage and temperature effects. For panels supported at top and bottom only, the source gives the teaching limit h ≤ 30t; other supports use Annex F-style relationships.
3.6 Flexural strength and orthogonal ratioSource §3.6
Masonry is anisotropic. Flexural strength therefore depends on whether the failure plane is parallel or perpendicular to the bed joints.
- fₓₖ₁
- Characteristic flexural strength for a failure plane parallel to bed joints; often the weaker direction.
- fₓₖ₂
- Characteristic flexural strength for a failure plane perpendicular to bed joints.
- μ
- Basic orthogonal ratio fₓₖ₁/fₓₖ₂ unless a permitted adjustment is justified.
Use the values associated with the actual masonry material, mortar and failure directions.
| Water absorption | Mortar | fₓₖ₁ N/mm² | fₓₖ₂ N/mm² |
|---|---|---|---|
| < 7% | M12 | 0.70 | 2.00 |
| < 7% | M6/M4 | 0.50 | 1.50 |
| < 7% | M2 | 0.40 | 1.20 |
| 7–12% | M12 | 0.50 | 1.50 |
| 7–12% | M6/M4 | 0.40 | 1.10 |
| 7–12% | M2 | 0.35 | 1.00 |
| > 12% | M12 | 0.40 | 1.10 |
| > 12% | M6/M4 | 0.30 | 0.90 |
| > 12% | M2 | 0.25 | 0.80 |
3.7 Applied moment and resistanceSource §3.7
Use the coefficient for the relevant support case, aspect ratio and failure direction.
Beneficial vertical compression may be considered only where the applicable route permits it and the correct load combination and sign are used.
| μ | h/l 0.50 | 0.75 | 1.00 | 1.25 | 1.50 |
|---|---|---|---|---|---|
| 1.00 | 0.045 | 0.059 | 0.071 | 0.079 | 0.085 |
| 0.50 | 0.056 | 0.073 | 0.083 | 0.090 | 0.095 |
| 0.35 | 0.064 | 0.080 | 0.089 | 0.095 | 0.100 |
| 0.30 | 0.067 | 0.082 | 0.091 | 0.097 | 0.101 |
| 0.25 | 0.071 | 0.085 | 0.094 | 0.099 | 0.103 |
3.8 Panels with openingsSource §3.8
A door or window interrupts the load path and may create side piers, a head panel and a sill panel. Large openings or irregular boundaries may require yield-line analysis or FEM rather than a simplified full rectangle.
- Check whether the opening creates a free edge.
- Check side-pier and head/sill proportions.
- Use conservative spans where support is uncertain.
- Report the governing subdivided panel.
3.9 Arching action and free-standing wallsSource §3.9
Use only when supports can resist arch thrust and detailing permits the compression mechanism.
A thin free-standing wall can have very low lateral capacity.
3.10 Lateral Panel Design CalculatorSource §3.10
Lateral Panel Design Calculator
Report panel ratios, orthogonal ratio, design pressure, moment demand, flexural resistance and utilisation for the selected reviewed coefficient.
- Inputs
- Panel height/length/thickness · Characteristic wind · Wind factor · fₓₖ₁ · fₓₖ₂ · Material factor · Reviewed α₂
- Outputs
- h/t · l/t · μ · W_Ed · M_Ed · M_Rd · Utilisation
- Status states
- Pass · Fail · Invalid input
- Validation
- Approved against the supplied worked-example results; project-specific verification remains required
Lateral Panel Design Calculator
Approved educational implementation reproducing the supplied source example.
The panel satisfies the simplified source flexural-strength check.
- h/t · l/t
- 13.95 · 19.53
- Orthogonal ratio μ
- 0.33
- Design pressure W_Ed
- 1.20 kN/m²
- Applied moment M_Ed
- 1.65 kNm/m
- Resistance M_Rd
- 2.57 kNm/m
- Utilisation
- 0.64
Calculation trail
μ = 0.30 / 0.90 = 0.33W_Ed = 1.50 × 0.80 = 1.20 kN/m²M_Ed = 0.078 × 1.20 × 4.20² = 1.65 kNm/mZ = 1000t²/6 = 7.704e+6 mm³/mM_Rd = 0.333 × Z = 2.57 kNm/m
3.11 WE-03 — Laterally loaded panelSource §3.11
WE-03 · Lateral panel check · Rev. B
Check a 4.2 m × 3.0 m, 215 mm thick masonry infill panel for characteristic wind pressure 0.8 kN/m2 using source support condition A.
- Geometry
h/t = 3000/215 = 13.95; l/t = 4200/215 = 19.53
Ratios within the source teaching range - Orthogonal ratio
μ = 0.30/0.90
μ = 0.33 - Coefficient
h/l = 0.71; selected source teaching lookup
α2 = 0.078 - Design pressure
WEd = 1.5(0.8)
1.20 kN/m2 - Applied moment
MEd = 0.078(1.20)(4.22)
1.65 kNm/m - Design flexural strength
fxd2 = 0.90/2.7
0.333 N/mm2 - Section modulus
Z = 1000(2152)/6
7.70 × 106 mm3/m - Resistance
MRd = 0.333(7.70 × 106)/106
2.56 kNm/m - Verification
1.65 ≤ 2.56
PASS
Result. The source panel passes the simplified flexural-strength check. Support condition, serviceability status, coefficient source and utilisation must remain visible.
3.12 WE-04 — Arching and free-standing wall capacitySource §3.12
WE-04 · Arching and free-standing wall · Rev. B
Use the Chapter 03 material data to compare a source arching check with free-standing wall capacity.
- Arching material
fd = 2.33/3.0 = 0.776 N/mm2 = 776 kN/m2; t = 215 mm; la = 3.0 m
Compression and la/t source conditions satisfied - Arching capacity
qlat,d = 776(0.215/3.0)2
3.98 kN/m2 > WEd 1.20 kN/m2 · conditional PASS - Half-brick free-standing wall
h = 1.2 m; t = 105 mm
WEd,cap ≈ 0.35 kN/m2 · very low - One-brick comparison
h = 1.2 m; t = 220 mm
WEd,cap ≈ 1.54 kN/m2
Result. Arching is an alternative conditional route, not an addition to the main flexural check. Free-standing wall capacity increases strongly with thickness.
3.13 Chapter summarySource §3.13
Key points
- Classify behaviour and supports before calculation.
- Check size limits before resistance.
- Use fₓₖ₁, fₓₖ₂, μ, α₂ and W_Ed consistently.
- Treat openings as load-path interruptions.
- Use arching only with verified thrust restraint.
Source references recorded by the supplied chapter
- EN 1996-1-1 Clause 6.3 and Annex E/F concepts
- UK NA Table NA.6 as recorded in the source
- Masonry Note Parts 3 and 4
- Updated interactive book Chapter 03