Eurocode 3 Verification

Benchmarking against SCI P364, Designers' Guide to EN 1993-1-1, EUR 22898 EN, and Worked Examples in EC3 & EC4.

Open Eurocode 3 Calculator

Benchmarks

126

test cases

Avg Difference

0.43%

vs. reference

Check Types

Methodology

The Eurocode 3 engine implements the requirements of EN 1993-1-1: General rules and rules for buildings. Verification is performed using high-quality benchmarks from Designers' Guide to EN 1993-1-1 Eurocode 3 (Gardner & Nethercot), SCI P364 (Steel Building Design: Worked Examples for Open Sections), Worked Examples in EC3 & EC4, and EUR 22898 EN (Commentary and Worked Examples to EN 1993-1-5).

Cross-section Resistance: Benchmarked for axial, bending, and shear according to Section 6.2 for all section classes.
Buckling Resistance: Flexural buckling (6.3.1) and Lateral-Torsional Buckling (6.3.2) benchmarked against analytical solutions for all member types.
Combined stability: Implements Annex B (Method 2) for interaction factors k_yy, k_yz, k_zy, k_zz across diverse loading scenarios.

Benchmark Results

Each row compares an engine result against a published reference value. The difference column shows the percentage deviation.

ID	Description	Section	Expected	Result	Diff %
EC3-01	406x178x54 UB flange class (pure bending)	406x178x54 UB	Class 1	Class 1	0.00%
EC3-02	406x178x54 UB web class (pure bending)	406x178x54 UB	Class 1	Class 1	0.00%
EC3-03	406x178x54 UB overall class (pure bending)	406x178x54 UB	Class 1	Class 1	0.00%
EC3-04	406x178x54 UB flange class (N=300kN)	406x178x54 UB	Class 1	Class 1	0.00%
EC3-05	406x178x54 UB web class (N=300kN)	406x178x54 UB	Class 2	Class 2	0.00%
EC3-06	406x178x54 UB overall class (N=300kN)	406x178x54 UB	Class 2	Class 2	0.00%
EC3-07	254x254x73 UC flange class (pure compression)	254x254x73 UC	Class 2	Class 2	0.00%
EC3-08	254x254x73 UC overall class	254x254x73 UC	Class 2	Class 2	0.00%
EC3-09	229x89 Channel flange class	229x89 Channel	Class 1	Class 1	0.00%
EC3-10	229x89 Channel web class	229x89 Channel	Class 1	Class 1	0.00%
EC3-11	229x89 Channel overall class	229x89 Channel	Class 1	Class 1	0.00%
EC3-12	CHS 244.5x10 overall class	CHS 244.5x10	Class 1	Class 1	0.00%
EC3-13	RHS 200x100x16 flange class	RHS 200x100x16	Class 1	Class 1	0.00%
EC3-14	RHS 200x100x16 web class	RHS 200x100x16	Class 1	Class 1	0.00%
EC3-15	RHS 200x100x16 overall class	RHS 200x100x16	Class 1	Class 1	0.00%
EC3-17	229x89 Channel Vpl,Rd	229x89 Channel	332 kN	332.1 kN	0.05%
EC3-18	UB 533x210x92 Mc,Rd	UB 533x210x92	649.0 kNm	649.0 kNm	0.00%
EC3-20	UB 406x178x74 rho factor (shear-bending)	UB 406x178x74	0.27	0.274	1.50%
	Rounding of the ρ factor intermediate value — textbook rounds to 2 significant figures mid-calculation, engine retains full precision.
EC3-21	UB 406x178x74 My,V,Rd (Aw per Eq 6.30)	UB 406x178x74	386.8 kNm	386.8 kNm	0.00%
EC3-22	H 305x305x240 Cl.6.2.9 biaxial interaction ratio	H 305x305x240	0.33	0.339	2.77%
	Textbook rounds reduced plastic moment MN,Rd and interaction terms to 2 significant figures. The engine retains full intermediate precision, leading to a slightly higher biaxial ratio.
EC3-23	UB 457x191x98 n ratio (N/Npl)	UB 457x191x98	0.477	0.477	0.08%
EC3-24	UB 457x191x98 a parameter	UB 457x191x98	0.395	0.395	0.10%
EC3-25	UB 457x191x98 MN,y,Rd	UB 457x191x98	342.2 kNm	342.2 kNm	0.01%
EC3-26	CHS 244.5x10 radius of gyration i	CHS 244.5x10	82.97 mm	82.97 mm	0.01%
EC3-27	CHS 244.5x10 λ_bar	CHS 244.5x10	0.56	0.555	0.83%
EC3-28	CHS 244.5x10 χ (curve a)	CHS 244.5x10	0.91	0.906	0.42%
EC3-29	CHS 244.5x10 Nb,Rd	CHS 244.5x10	1836.5 kN	1836.5 kN	0.00%
EC3-30	CHS 244.5x10 buckling ratio (NEd=1630 kN)	CHS 244.5x10	0.888	0.888	0.00%
EC3-31	H 305x305x240 iy	H 305x305x240	144.86 mm	144.85 mm	0.01%
EC3-32	H 305x305x240 λ_bar_y	H 305x305x240	0.23	0.234	1.65%
	Textbook rounds λ̄ to 2 decimal places. Engine retains full precision from section property calculations.
EC3-33	H 305x305x240 χ_y (curve b)	H 305x305x240	0.99	0.988	0.20%
EC3-34	H 305x305x240 iz	H 305x305x240	81.46 mm	81.47 mm	0.01%
EC3-35	H 305x305x240 λ_bar_z	H 305x305x240	0.59	0.594	0.65%
EC3-36	H 305x305x240 χ_z (curve c)	H 305x305x240	0.79	0.789	0.12%
EC3-37	RHS 200x100x16 iy	RHS 200x100x16	66.56 mm	66.57 mm	0.01%
EC3-38	RHS 200x100x16 λ_bar_y	RHS 200x100x16	1.42	1.416	0.31%
EC3-39	RHS 200x100x16 χ_y (curve a)	RHS 200x100x16	0.41	0.410	0.10%
EC3-40	RHS 200x100x16 iz	RHS 200x100x16	37.17 mm	37.17 mm	0.01%
EC3-41	RHS 200x100x16 λ_bar_z	RHS 200x100x16	0.84	0.845	0.59%
EC3-42	RHS 200x100x16 χ_z (curve a)	RHS 200x100x16	0.77	0.769	0.12%
EC3-43	UC 203x203x46 λ_bar_y	UC 203x203x46	0.65	0.653	0.46%
EC3-44	UC 203x203x46 χ_y (curve b)	UC 203x203x46	0.81	0.810	0.05%
EC3-45	UC 203x203x46 λ_bar_z	UC 203x203x46	0.56	0.561	0.24%
EC3-46	UC 203x203x46 χ_z (curve c)	UC 203x203x46	0.81	0.808	0.24%
EC3-47	UB 762x267x173 Mcr Segment CD	UB 762x267x173	4311 kNm	4311 kNm	0.01%
EC3-48	UB 762x267x173 λ_LT Segment CD	UB 762x267x173	0.63	0.629	0.13%
EC3-49	UB 762x267x173 χ_LT Segment CD (general)	UB 762x267x173	0.82	0.822	0.26%
EC3-50	UB 762x267x173 λ_LT Segment BC	UB 762x267x173	0.55	0.547	0.54%
EC3-51	UB 762x267x173 χ_LT Segment BC (general)	UB 762x267x173	0.86	0.863	0.32%
EC3-52	UB 762x267x173 Mb,Rd Segment BC	UB 762x267x173	1469 kNm	1471 kNm	0.10%
EC3-53	UB 457x191x82 λ_LT	UB 457x191x82	0.64	0.641	0.20%
EC3-54	UB 457x191x82 χ_LT (general)	UB 457x191x82	0.82	0.816	0.51%
EC3-55	UB 457x191x82 Mb,Rd	UB 457x191x82	411 kNm	411 kNm	0.06%
EC3-56	UC 203x203x46 Cl.6.3.3 ratio (Annex B)	UC 203x203x46	0.51	0.503	1.37%
	Interaction factors kyy, kzy computed with full precision vs textbook's 2 d.p. rounding of intermediate χ and λ̄ values.
EC3-57	H 305x305x240 Cl.6.3.3 ratio (Annex B)	H 305x305x240	0.97	0.967	0.34%
EC3-58	RHS 200x100x16 Cl.6.3.3 ratio (Annex B)	RHS 200x100x16	0.94	0.947	0.73%
EC3-62	533x210x92 UKB shear area Av	533x210x92 UKB	5723.6 mm²	5723.6 mm²	0.00%
EC3-63	533x210x92 UKB Vpl,Rd	533x210x92 UKB	909 kN	909 kN	0.03%
EC3-64	533x210x92 UKB VEd/Vc,Rd	533x210x92 UKB	0.297	0.297	0.03%
EC3-66	533x210x92 UKB MEd/Mc,Rd	533x210x92 UKB	0.831	0.831	0.00%
EC3-70	457x191x67 Av	457x191x67 UKB	4093.57 mm²	4093.57 mm²	0.00%
EC3-71	457x191x67 Vpl,Rd	457x191x67 UKB	650 kN	650 kN	0.01%
EC3-72	457x191x67 Mc,Rd	457x191x67 UKB	404.25 kNm	404.25 kNm	0.00%
EC3-73	457x191x67 Mcr uniform	457x191x67 UKB	134.2 kNm	133.7 kNm	0.37%
EC3-74	457x191x67 Mcr with C1=2.65	457x191x67 UKB	355.7 kNm	354.2 kNm	0.42%
EC3-75	457x191x67 λ_LT	457x191x67 UKB	1.07	1.068	0.19%
EC3-76	457x191x67 χ_LT base	457x191x67 UKB	0.60	0.598	0.27%
EC3-77	457x191x67 f factor	457x191x67 UKB	0.83	0.833	0.37%
EC3-78	457x191x67 χ_LT,mod	457x191x67 UKB	0.72	0.718	0.24%
EC3-79	457x191x67 Mb,Rd	457x191x67 UKB	291 kNm	290.4 kNm	0.22%
EC3-80	457x191x67 MEd/Mb,Rd	457x191x67 UKB	0.89	0.896	0.61%
EC3-81	305x305x97 UKC flange class	305x305x97 UKC	Class 3	Class 3	0.00%
EC3-82	305x305x97 UKC web class	305x305x97 UKC	Class 1	Class 1	0.00%
EC3-83	305x305x97 UKC overall class	305x305x97 UKC	Class 3	Class 3	0.00%
EC3-84	305x305x97 Av	305x305x97 UKC	3517.38 mm²	3517.38 mm²	0.00%
EC3-85	305x305x97 Vpl,Rd	305x305x97 UKC	721 kN	721 kN	0.01%
EC3-86	305x305x97 Mc,Rd (elastic, Class 3)	305x305x97 UKC	514.75 kNm	514.75 kNm	0.00%
EC3-87	305x305x97 MEd/Mc,Rd	305x305x97 UKC	0.641	0.641	0.00%
EC3-88	305x305x97 Mcr uniform	305x305x97 UKC	460.5 kNm	461.4 kNm	0.20%
EC3-89	305x305x97 Mcr with C1=1.32	305x305x97 UKC	607.7 kNm	609.1 kNm	0.23%
EC3-90	305x305x97 λ_LT	305x305x97 UKC	0.92	0.919	0.08%
EC3-91	305x305x97 χ_LT base	305x305x97 UKC	0.74	0.749	1.15%
	Engine uses continuous LTB curve formula; textbook rounds intermediate Φ_LT to 2 d.p.
EC3-92	305x305x97 χ_LT,mod	305x305x97 UKC	0.79	0.799	1.14%
	Cascading from EC3-91: textbook rounds Φ_LT to 2 d.p., propagating through to χ_LT,mod.
EC3-93	305x305x97 Mb,Rd	305x305x97 UKC	407 kNm	411 kNm	1.05%
	Cascading from χ_LT,mod precision difference (EC3-91/92). Engine gives a slightly higher Mb,Rd.
EC3-94	305x305x97 MEd/Mb,Rd	305x305x97 UKC	0.81	0.802	0.94%
EC3-95	356x368x129 UKC flange class	356x368x129 UKC	Class 3	Class 3	0.00%
EC3-96	356x368x129 UKC overall class	356x368x129 UKC	Class 3	Class 3	0.00%
EC3-97	356x368x129 Nc,Rd	356x368x129 UKC	5658 kN	5658 kN	0.00%
EC3-98	356x368x129 NEd/Nc,Rd	356x368x129 UKC	0.619	0.619	0.00%
EC3-99	356x368x129 λ_bar_z	356x368x129 UKC	0.82	0.821	0.11%
EC3-100	356x368x129 χ_z	356x368x129 UKC	0.65	0.649	0.15%
EC3-101	356x368x129 Nb,Rd	356x368x129 UKC	3678 kN	3672 kN	0.16%
EC3-102	356x368x129 buckling ratio	356x368x129 UKC	0.952	0.953	0.16%
EC3-103	305x305x97 λ_bar_y	305x305x97 UKC	0.516	0.516	0.05%
EC3-104	305x305x97 χ_y	305x305x97 UKC	0.87	0.877	0.82%
EC3-105	305x305x97 Nb,y,Rd	305x305x97 UKC	2943 kN	2967 kN	0.82%
EC3-106	305x305x97 λ_bar_z	305x305x97 UKC	0.449	0.449	0.05%
EC3-107	305x305x97 χ_z	305x305x97 UKC	0.88	0.871	1.00%
	Engine uses continuous buckling curve c formula; textbook rounds intermediate Φ to 2 d.p.
EC3-108	457x191x82 Vpl,Rd	457x191x82 UKB	756 kN	756 kN	0.03%
EC3-109	457x191x82 χ_LT,mod (6.3.2.3 rolled)	457x191x82 UKB	0.92	0.882	4.15%
	Engine uses the NCCI SN003 closed-form Mcr formula (standard analytical method). The textbook derives Mcr from LTBeam finite element software, which yields ~4% lower λ_LT for this section. The analytical result is conservative (safe side).
EC3-110	457x191x82 Mb,Rd	457x191x82 UKB	463 kNm	444 kNm	4.10%
	Cascading from Mcr method difference above. Engine uses NCCI SN003 analytical Mcr; textbook uses LTBeam FE software. Result is conservative (safe side).
EC3-111	203x203x46 χ_y	203x203x46 UKC	0.80	0.810	1.20%
	Textbook rounds intermediate Φ to 2 d.p. in buckling curve b; engine retains full precision.
EC3-112	203x203x46 χ_z	203x203x46 UKC	0.47	0.472	0.49%
EC3-113	203x203x46 χ_LT	203x203x46 UKC	0.83	0.846	1.93%
	Engine’s SCI/NCCI C1 polynomial approximation overestimates C1 for this moment diagram, yielding a lower λ_LT (0.725 vs textbook 0.76 via LTBeam) and higher χ_LT. The structural interaction ratio remains within 1.6% of the textbook.
EC3-114	203x203x46 Cl.6.3.3 combined ratio	203x203x46 UKC	0.98	0.996	1.59%
	Combined cascading effect from χ_y (EC3-111) and χ_LT (EC3-113) C1 approximation differences.
EC3-115	457x191x67 χ_y (S355)	457x191x67 UKB	0.94	0.946	0.66%
EC3-116	457x191x67 χ_z (S355)	457x191x67 UKB	0.62	0.627	1.14%
	Textbook rounds intermediate Φ to 2 d.p. in buckling curve b; engine retains full precision.
EC3-117	457x191x67 χ_LT (S355, Class 3)	457x191x67 UKB	0.88	0.825	6.24%
	Engine uses NCCI SN003 analytical Mcr with fork support (free warping) at each 3m segment. The textbook uses LTBeam FE software which models warping continuity at the intermediate restraint, giving a higher Mcr. Lower χ_LT = lower capacity prediction = conservative (safe side).
EC3-118	457x191x67 Cl.6.3.3 combined ratio (Class 3)	457x191x67 UKB	0.88	0.934	6.11%
	Cascading from χ_LT difference above. Engine’s analytical Mcr (fork support) vs textbook’s LTBeam (warping continuity) propagates into the 6.3.3 interaction factors. Result is conservative (safe side).
EC3-119	EUR 22898 §16: Panel I plate slenderness (450×12, S355)	Plate panel 450×12	0.811	0.812	0.06%
EC3-120	EUR 22898 §16: Panel I reduction factor ρ	Plate panel 450×12	0.899	0.898	0.08%
EC3-121	EUR 22898 §16: Panel III plate slenderness (288×6, S355)	Plate panel 288×6	1.038	1.039	0.06%
EC3-122	EUR 22898 §16: Panel III reduction factor ρ	Plate panel 288×6	0.759	0.759	0.02%
EC3-123	EUR 22898 §15: Bottom flange plate slenderness (700×26, S420)	Plate panel 700×26	0.63	0.634	0.58%
EC3-124	EUR 22898 §15: Stiffener plate slenderness (350×8, S420)	Plate panel 350×8	1.03	1.030	0.03%
EC3-125	EUR 22898 §15: Stiffener reduction factor ρ	Plate panel 350×8	0.763	0.764	0.09%
EC3-126	EUR 22898 §15: Inclined web plate slenderness (391×8, S420)	Plate panel 391×8	1.15	1.150	0.03%
EC3-127	EUR 22898 §15: Inclined web reduction factor ρ	Plate panel 391×8	0.703	0.703	0.01%
EC3-128	EUR 22898 §15: kσ for web ψ=−1.30 (Table 4.1)	EN 1993-1-5 Table 4.1	31.63	31.63	0.00%
	EUR 22898 EN p.178 uses an approximate formula giving kσ=32.5; the correct Table 4.1 formula gives 31.63.
EC3-129	EUR 22898 §15: ρ web bending at λp=1.07, ψ=−1.30	Plate panel (bending)	0.853	0.853	0.01%
EC3-130	EUR 22898 Eq 4.1: ρ internal λp=2.0 ψ=1	EN 1993-1-5 Eq 4.1	0.445	0.445	0.00%
EC3-131	EUR 22898 Eq 4.2: ρ outstand λp=1.5	EN 1993-1-5 Eq 4.2	0.583	0.583	0.02%
EC3-132	EUR 22898 §15.2: Stiffener ρ at λp=0.857	Plate panel (stiffener)	0.868	0.867	0.08%
EC3-133	254x254x73 UC Compression Resistance Nc,Rd (S355)	254x254x73 UC	3305 kN	3305.1 kN	0.00%
EC3-134	CHS 244.5x10 Section Compression Npl,Rd (S275)	CHS 244.5x10	2026.75 kN	2025.9 kN	0.04%
EC3-135	RHS 200x100x16 Bending Resistance Mc,Rd (S355, Class 1)	RHS 200x100x16	174.3 kNm	174.3 kNm	0.00%

Disclaimer: This verification page is provided for informative purposes only and does not constitute a guarantee of accuracy for all possible configurations. While we strive to ensure the correctness of our calculations through rigorous benchmarking, no software is entirely free of defects. Engineers must exercise independent professional judgement and verify results through their own checks before relying on any output for design or construction decisions. AutoCalcs accepts no liability for errors, omissions, or any consequences arising from the use of this software.