About Masonry Wall Design Calculator
The masonry wall design calculator determines the axial and lateral load capacity of an unreinforced or reinforced masonry wall per Eurocode 6, with TMS 402 and AS 3700 support. It is used by structural engineers to check characteristic strength, slenderness, eccentricity, and utilization for a chosen block and mortar combination.
Select the block type and mortar class, set the wall height, length, and thickness, choose the support condition, and enter the axial and lateral loads with any load eccentricity. The tool returns the characteristic and design strengths, the slenderness ratio, the capacity reduction factor, and axial and lateral utilization in real time.
How It Works
- Compute the characteristic compressive strength fk = K * fb^0.7 * fm^0.3 from the normalized unit strength and the mortar strength (EC6 Group 1).
- Divide by the partial factor gammaM (2.5 unreinforced, 2.0 reinforced) to get the design strength fd.
- Find the slenderness ratio hef/tef using the effective-height factor for the support condition, and a capacity reduction factor Phi from the load eccentricity (clamped to a minimum of 0.05t) and optional slenderness reduction.
- Compute the axial capacity NRd = Phi * fd * A and the lateral capacity from the flexural tensile strength, then report axial and lateral utilization with a pass/fail verdict.
Worked Example
A 140 mm clay-brick wall (fb = 20 MPa) in M10 mortar (fm = 10 MPa) gives fk = 0.55 * 20^0.7 * 10^0.3 = 8.94 MPa and, for unreinforced masonry, fd = 8.94 / 2.5 = 3.57 MPa. A 2700 mm high pinned-pinned wall has slenderness hef/tef = 2700/140 = 19.3. With the eccentricity at the 0.05t minimum, Phi = 1 - 2(0.05) = 0.90, so the axial capacity per metre length is NRd = 0.90 * 3.57 * (1000 * 140) / 1000 = 450.3 kN.
Formulas
- Characteristic strength (EC6, Group 1)
fk = K * fb^0.7 * fm^0.3- Design strength
fd = fk / gammaM- Slenderness ratio
SR = hef / tef = (factor * h) / t- Axial capacity
NRd = Phi * fd * A
Standards & References
- Eurocode 6 (EN 1996-1-1)
- TMS 402
- AS 3700
Frequently Asked Questions
How is the characteristic strength of masonry calculated?
Under Eurocode 6 for Group 1 units, fk = K * fb^0.7 * fm^0.3 where K is 0.55, fb is the normalized unit compressive strength, and fm is the mortar compressive strength. The tool reads fb and fm from the selected block and mortar.
What partial factor is applied to get the design strength?
The design strength is fd = fk / gammaM. The tool uses gammaM = 2.5 for unreinforced masonry and 2.0 for reinforced masonry, consistent with Eurocode 6 recommended values.
How does eccentricity reduce the wall capacity?
The capacity reduction factor Phi starts from 1 - 2*(e/t), with the eccentricity e clamped to a minimum of 0.05t. When the slenderness reduction is enabled, an additional term proportional to the square of the slenderness ratio is subtracted.
Does the calculator handle lateral (out-of-plane) loads?
Yes. It estimates the lateral capacity from the flexural tensile strength (taken as 0.1*fk) and the wall section modulus over the effective height, then reports the lateral utilization alongside the axial check.