VC-14 — EC6 Wall Vertical Resistance vs Published Worked Example

Module: vernastruct.codes.ec6.check_masonry_wall_ec6 Code basis: EN 1996-1-1 §6.1.2 + Annex G — N_Rd = Φ·t·f_d with Φ_m = A1·e^(−u²/2), λ_t = (h_ef/t_ef)·√(f_k/E). Cross-check source (task 2.2): published worked example — Structville, "Design of Masonry Walls (EN 1996-1)": 150 mm aggregate-concrete block wall, restrained on all four edges. https://structville.com/design-of-masonry-walls-en-1996 Status: ✅ PASS — N_Rd reproduced to 4 significant figures (88.787 vs 88.786 kN/m); Φ_m to 0.02 %.

1. Why this case matters

VC-11 verified the EC6 engine against our own Annex G hand calculation. This case checks the same engine against an independently published example, and exercises paths VC-11 did not:

the effective-height factor ρ (all-edges-supported, ρ₄ = 0.64),
the 0.05·t minimum-eccentricity floor governing over e_init = h_ef/450,
a non-default γ_M = 3.0 (Category II units, execution class 2 — the UK NA value used by the source; our default 2.2 is an explicit argument),
the EN default stiffness E = 1000·f_k branch (our adobe work deliberately overrides it; here it must reproduce the European standard case exactly).

2. Published inputs

Input	Value
Wall	t = 150 mm, h = 2.70 m, all edges supported → ρ₄ = 0.64, h_ef = 1.728 m
Masonry	Group 2 concrete units, f_b = 3.77 MPa, M2 mortar → K = 0.70, f_k = 2.182 MPa
Partial factor	γ_M = 3.00
Stiffness	E = 1000·f_k = 2182 MPa
Design load	N_Ed at mid-height = 43.771 kN/m (γ_G 1.35 × (21 + self-wt to mid) + γ_Q 1.5 × 7)

3. Published results vs software

Quantity	Published	VernaStruct	Diff
Slenderness h_ef/t_ef	11.5	11.52	rounding
e_i = e_mk (0.05t floor)	7.5 mm	7.500	exact
Φ_i	0.900	0.9000	exact
Φ_m (Annex G)	0.814	0.8138	−0.02 %
f_d	0.727 MPa	0.7273	rounding
N_Rd	88.786 kN/m	88.787	0.00 %
Utilization	0.49 (PASS)	0.493 (PASS)	—

Pinned as tests/test_codes.py::test_vc14_ec6_matches_published_example.

4. Notes

The published example floors both eccentricities at 0.05·t = 7.5 mm because e_init = 1728/450 = 3.84 mm is smaller — confirming our floor logic (§6.1.2.2(2)) against independent practice.
The source neglects wind for the vertical check (e_mk stays at the floor); our M_mid_kNm_m input remains available for combined cases.
Together VC-11 + VC-14 bracket the two stiffness regimes: the published E = 1000·f_k European default (this case, exact match) and the measured low-E adobe case (VC-11, where the default would overstate capacity ~10 %).