Vertically Loaded Unreinforced Masonry Walls — Masonry Design to Eurocode 6

Illustrative masonry course visual showing brick and block cavity-wall materials; not a construction detail. — Original course visual generated for STRUCTURA Academic. Use the reviewed lesson diagrams—not this editorial image—for technical interpretation.

StandardEN 1996-1-1 with UK teaching references

Source1 source file

Review stateApproved · 2026-08-19

LEARNING OUTCOMES

After this chapter, you should be able to

Distinguish crushing-sensitive and buckling-sensitive behaviour.
Calculate actions at top, mid-height and bottom.
Select effective height and effective thickness.
Apply minimum eccentricity and reduction factors.
Report utilisation and the governing location.

2.1 Purpose and design questionSource §2.1

A vertically loaded masonry wall must not be checked by compression stress alone. The design must consider how load reaches the wall, how floors or roofs restrain it, and whether eccentricity and slenderness reduce usable resistance.

2.2 NotationSource §2.2

Notation used for vertically loaded walls
Symbol	Meaning	Typical unit
N_Ed	Design vertical action applied to the wall	kN/m
N_Rd	Design vertical resistance	kN/m
h, h_ef	Clear and effective wall height	mm or m
t, t_ef	Wall and effective thickness	mm
e_i, e_m, e_init	End, mid-height and initial eccentricity	mm
Φ	Capacity-reduction factor for eccentricity and slenderness	—
f_k, f_d	Characteristic and design masonry compressive strength	N/mm²

2.3 Behaviour under vertical loadingSource §2.3

A short wall is usually crushing-sensitive. A tall or slender wall may become unsafe before reaching crushing strength because eccentricity and deflection reduce resistance. Check the wall at top, bottom and mid-height.

Vertical resistance idea

N_Rd = Φ t f_d

For a one-metre wall strip, t is the structural thickness per metre run.

Figure 2.R — regenerated vertical-wall review diagram showing the three critical locations, effective height and a deflected load path.Approved original STRUCTURA academic diagram

2.4 Vertical wall design procedureSource §2.4

Vertical wall design sequence
Step	Design action	Main output
1	Evaluate ULS floor, roof and wall self-weight actions.	Top, mid-height and bottom design actions
2	Determine effective height from floor/roof and side restraint.	Effective height
3	Determine effective thickness from wall form and valid stiffening assumptions.	Effective structural thickness
4	Check slenderness ratio.	Slenderness status
5	Calculate moments and eccentricities.	End and mid-height eccentricities
6	Obtain capacity-reduction factors.	End and mid-height Φ
7	Calculate resistance and compare with design action.	Utilisation and governing location

2.5 Effective heightSource §2.5

Effective height controls the buckling-sensitive part of the check. Better top, bottom and side restraint produces a smaller effective height. The source teaching example uses 0.75 for reinforced-concrete slab restraint with small eccentricity; timber floors or weak restraint are normally more conservative.

Effective height

h_ef = ρ_n h

Select ρ_n only from the applicable restraint condition and verified design source.

2.6 Effective thicknessSource §2.6

For a single-leaf wall, effective thickness is normally the actual structural masonry thickness. A coefficient for piers or stiffening may be used only where geometry, bonding, detailing and the load path justify it.

Piered or stiffened wall teaching form

t_ef = ρ_t t

Do not include plaster as structural thickness unless the applicable method explicitly allows it.

2.7 Slenderness ratioSource §2.7

Simplified teaching limit

λ = h_ef / t_ef ≤ 27

If exceeded, improve restraint or thickness, add valid stiffening, or use a more detailed method. Do not force a passing result.

2.8 Moments, axial loads and eccentricitySource §2.8

Floor reactions may introduce moment into the wall. Eccentricity is related to bending moment divided by vertical load, with allowances for initial eccentricity and lateral-load eccentricity where relevant.

Top or bottom eccentricity

e_i = M_i / N_i + e_he ± e_init

For an internal loadbearing wall without lateral load, e_he may be zero.

Initial eccentricity

e_init = h_ef / 450

The minimum eccentricity rule must also be checked.

2.9 Capacity-reduction factorSource §2.9

End reduction factor

Φ_i = 1 − 2e_i / t

Used at top and bottom where end eccentricity is known.

Mid-height concept

Φ_m = A₁ e^−u2/2

The mid-height value is normally obtained from the applicable Annex G relationship or chart. The smallest relevant factor governs.

2.10 Vertical resistance checkSource §2.10

Final ULS check

N_Ed ≤ N_Rd = Φ t f_d = Φ t f_k / γ_M

Normally reported per metre run of wall for this chapter.

Possible design responses
Governing problem	Possible response
High slenderness	Increase thickness, reduce clear height, add a valid stiffening wall or improve restraint.
High eccentricity	Improve bearing detail, reduce transferred moment or change wall layout.
Low material strength	Use suitable stronger units/mortar or change wall type.
High vertical action	Increase thickness, add designed piers or redistribute load.

2.11 Vertical Wall Design CalculatorSource §2.11

APPROVED ACADEMIC CALCULATOR

Vertical Wall Design Calculator

Expose the effective-height, slenderness, eccentricity, reduction-factor and vertical-resistance trail at top, mid-height and bottom.

Inputs: Clear height · Height factor · Structural thickness · Characteristic strength · Material factor · Top/mid/bottom actions · Reviewed mid-height Φ
Outputs: Effective height · Slenderness · Eccentricity · Reduction factors · Design strength · Governing utilisation
Status states: Pass · Fail · Invalid input
Validation: Approved against the supplied worked-example results; project-specific verification remains required

APPROVED ACADEMIC CALCULATOR · WE-02

Vertical Wall Design Calculator

Approved educational implementation reproducing the supplied source example.

PASS

The source-example wall satisfies the simplified vertical resistance checks.

Effective height: 2250 mm
Slenderness hₑf/t: 10.00
Adopted eccentricity: 11.25 mm
End / mid-height Φ: 0.90 / 0.85
Design strength f_d: 0.777 N/mm²
Governing utilisation: 0.92

Calculation trail

hₑf = 3.00 × 0.75 = 2250 mm
λ = 2250 / 225 = 10.00
e = max(hₑf/450, 0.05t) = 11.25 mm
Φend = 1 − 2e/t = 0.90
N_Rd,mid = 0.85 × 225 × 0.777 = 148.54 kN/m

2.12 WE-02 — Complete vertically loaded wallSource §2.12

WORKED EXAMPLE

WE-02 · MAS-WE-02 · Rev. B

Check a 225 mm masonry wall in a three-storey house supporting reinforced-concrete one-way slabs. Clear height is 3.0 m; the source uses reinforced-concrete restraint and no lateral-load eccentricity.

ULS floor load
g_k = 0.125(25) + 0.75 = 3.875 kN/m²; q_Ed = 1.35(3.875) + 1.5(2.0)
Design floor load = 8.23 kN/m²
Load take-down
N_Ed,top = 121.81; N_Ed,mid = 132.94; N_Ed,bot = 144.08 kN/m
Bottom has the largest applied action
Effective geometry
h_ef = 0.75(3.0) = 2.25 m; t_ef = 225 mm
h_ef = 2250 mm; t_ef = 225 mm
Slenderness
h_ef/t_ef = 2250/225 = 10
10 ≤ 27 · PASS
Minimum eccentricity
e_init = 2250/450 = 5.0 mm; e_min = 0.05(225) = 11.25 mm
Adopt 11.25 mm
Reduction factors
Φ_top = Φ_bot = 1 − 2(11.25)/225 = 0.90; Φ_mid ≈ 0.85
Smallest Φ = 0.85
Design strength
f_d = 2.33/3.0 = 0.776 N/mm²
Teaching material selection recorded
Resistance
N_Rd,mid = 0.85(225)(0.776) = 148.4; N_Rd,bot = 0.90(225)(0.776) = 157.1 kN/m
Governing utilisation ≈ 0.92 · PASS

Result. The source example passes. The bottom load gives the largest utilisation; mid-height remains important because slenderness and eccentricity control its reduction factor.

2.13 Chapter summarySource §2.13

Key points

Check top, bottom and mid-height.
Select effective height and thickness from real restraint and structural geometry.
Apply minimum eccentricity and show reduction factors.
Report the governing location and explain failures.

Source references recorded by the supplied chapter

EN 1996-1-1 Clause 6.1.2.1 and Annex G concepts
Masonry Note Part 2 Sections 3.1–3.10
Updated interactive book Chapter 02