Engineering Eurocode 6 (EC6) Masonry Design

Quick helper for Eurocode 6 masonry design: estimate wall capacity, check slenderness and partial factors, and understand the key formulas from EN 1996.

EN 1996-1-1 overview Unreinforced masonry Preliminary design aid

Eurocode 6 Masonry Quick Calculators

1. Design Axial Compressive Resistance of a Masonry Wall

Simplified check for an axially loaded unreinforced masonry wall according to the general format of EN 1996‑1‑1. This is for preliminary sizing only – always verify with the full code and National Annex.

Typical for unreinforced masonry; use National Annex values.

Between lateral supports; consider end conditions.

User-chosen; see EN 1996‑1‑1 clauses for detailed rules.

Set 1.0 if you only want NRd as per EC6 format.

Results

Design compressive strength of masonry: 2.50 N/mm²

Design axial resistance of wall (NRd): 1,260 kN

NRd is computed as φ · fd · t · leff / γRd, with dimensions converted to m².

What is Eurocode 6 (EN 1996)?

Eurocode 6 (EN 1996) is the European standard for the design of masonry structures. It covers unreinforced, reinforced, prestressed and confined masonry, and is intended to be used together with EN 1990 (Basis of structural design) and EN 1991 (Actions on structures).

This page focuses on unreinforced loadbearing masonry walls and provides quick helper calculations for:

  • Converting characteristic strength fk to design strength fd.
  • Estimating axial compressive resistance NRd of a wall.
  • Checking basic slenderness heff / t against a user‑defined limit.

It is a preliminary design aid. For final design you must always refer to the full text of EN 1996‑1‑1 and the relevant National Annex.

Key Eurocode 6 design concepts

1. Masonry compressive strength

Eurocode 6 defines the characteristic compressive strength of masonry fk as a function of:

  • Normalized compressive strength of units, fb.
  • Mortar strength, fm.
  • Unit type (clay, concrete, autoclaved aerated concrete, etc.).

The general format is:

\( f_k = K \cdot f_b^{\alpha} \cdot f_m^{\beta} \)

where K, α and β are coefficients given in EN 1996‑1‑1 for each masonry family.

The design compressive strength is then:

\( f_d = \dfrac{f_k}{\gamma_M} \)

γM is the material partial factor for masonry, specified in the National Annex.

2. Axial compressive resistance of a wall

For a straight, axially loaded wall without significant bending, Eurocode 6 allows the design axial resistance to be expressed in the form:

\( N_{Rd} = \varphi \cdot f_d \cdot t \cdot l_{eff} \)

  • φ – reduction factor for slenderness and eccentricity (≤ 1.0).
  • fd – design compressive strength of masonry (N/mm²).
  • t – wall thickness (mm).
  • leff – effective length between lateral supports (mm).

In the calculator above, we convert t and leff from mm to m to obtain NRd in kN. The factor φ is left as a user input because its exact value depends on:

  • Slenderness ratio heff / t.
  • Eccentricity of loading (top, bottom, or combined).
  • End conditions and lateral restraint.

3. Slenderness and effective height

The slenderness ratio of a wall is defined as:

\( \lambda = \dfrac{h_{eff}}{t} \)

heff is the effective height, depending on boundary conditions (fixed, pinned, etc.).

Eurocode 6 provides maximum slenderness limits for different support conditions and loading arrangements. If λ exceeds the limit, second‑order effects and buckling must be considered, or the wall geometry must be modified (e.g. thicker wall, reduced height, intermediate supports).

Worked example (illustrative only)

Suppose you have an internal loadbearing wall with:

  • fk = 7.5 N/mm², γM = 2.7 → fd ≈ 2.78 N/mm².
  • Thickness t = 240 mm.
  • Effective length leff = 3.0 m (3000 mm).
  • Reduction factor φ = 0.7 (moderate slenderness and eccentricity).

The design axial resistance is:

\( N_{Rd} = \varphi \cdot f_d \cdot t \cdot l_{eff} \)

\( = 0.7 \times 2.78 \times 0.24 \times 3.0 \,\text{MN} \approx 1.40 \,\text{MN} = 1400 \,\text{kN} \)

You would then compare the design axial load NEd from load combinations (EN 1990/EN 1991) with NRd. If NEd ≤ NRd and all other checks (slenderness, shear, serviceability) are satisfied, the wall is adequate in axial compression.

Limitations and good practice

  • This tool does not replace a full Eurocode 6 design or engineering judgement.
  • Always use the National Annex for γM, φ rules, and slenderness limits.
  • Check other limit states: shear, in‑plane and out‑of‑plane bending, serviceability (cracking, deflection).
  • Consider durability, workmanship, and detailing requirements from EN 1996‑2.

Frequently asked questions

Is this calculator approved for code‑compliant design?

No. It is intended as an educational and preliminary sizing tool. For code‑compliant design you must follow EN 1996‑1‑1, EN 1996‑2, EN 1990, EN 1991 and the relevant National Annex, and have the design checked by a qualified structural engineer.

Can I use this for reinforced or confined masonry?

The simplified formulas and examples here are aimed at unreinforced loadbearing masonry. Reinforced, prestressed or confined masonry require additional checks and detailing rules that are not covered by this quick tool.

Where do I get fk values?

fk values are usually provided by the masonry manufacturer in product documentation (e.g. CE marking, DoP) or can be calculated from unit and mortar strengths using the tables and formulas in EN 1996‑1‑1. Always verify that the values correspond to the specific unit type and mortar class you are using.