StruCla against Technosoft Raamwerken: steel beam HEA 180
A rolled steel beam HEA 180 in S235 on two supports, span 4.15 m, permanent load G = 2.08 kN/m and variable load Q = 9.00 kN/m, plus self weight, consequence class 1, ψ0 = 0.4, ψ1 = 0.5, ψ2 = 0.3, no lateral restraint between the supports, load on the top flange. The same beam was rebuilt in StruCla; every StruCla value comes from StruCla's own report.
0.489 / 0.488unity check, lateral torsional buckling (StruCla / Technosoft)
31.82 / 31.8 kNmdesign moment, ULS 6.10b
25 of 44values equal within the rounding of the Technosoft output; 18 differ by less than 1.5 % for a stated reason, 1 by a method choice
Technosoft prints 2 decimals (sometimes 1). A difference smaller than half a unit of its last printed digit counts as equal. Green: equal within the rounding. Yellow: a small difference with a stated reason. Blue: a different method, both allowed by the standard.
1. Forces and reactions (ULS) per combination: reaction R, bending moment M, shear force V
| Quantity | Technosoft | StruCla | Difference | Note |
|---|---|---|---|---|
| BC1 1.22·G: reaction R | 6.14 kN | 6.165 kN | +0.41 % | Technosoft prints 1.22 but calculates with 0.9 · 1.35 = 1.215 |
| BC1 1.22·G: moment M | 6.4 kNm | 6.40 kNm | -0.06 % | Technosoft prints 1.22 but calculates with 0.9 · 1.35 = 1.215 |
| BC1 1.22·G: shear force V | 6.1 kN | 6.17 kN | +1.07 % | Technosoft prints 1.22 but calculates with 0.9 · 1.35 = 1.215 |
| BC2 0.9·G: reaction R | 4.55 kN | 4.548 kN | -0.04 % | |
| BC2 0.9·G: moment M | 4.7 kNm | 4.72 kNm | +0.39 % | |
| BC2 0.9·G: shear force V | 4.5 kN | 4.55 kN | +1.07 % | |
| BC3 6.10a 1.22·G + 1.35·ψ0·Q: reaction R | 16.22 kN | 16.250 kN | +0.18 % | Technosoft prints 1.22 but calculates with 0.9 · 1.35 = 1.215 |
| BC3 6.10a 1.22·G + 1.35·ψ0·Q: moment M | 16.8 kNm | 16.86 kNm | +0.35 % | Technosoft prints 1.22 but calculates with 0.9 · 1.35 = 1.215 |
| BC3 6.10a 1.22·G + 1.35·ψ0·Q: shear force V | 16.2 kN | 16.25 kN | +0.31 % | Technosoft prints 1.22 but calculates with 0.9 · 1.35 = 1.215 |
| BC4 6.10b 1.08·G + 1.35·Q (governing): reaction R | 30.67 kN | 30.669 kN | -0.00 % | |
| BC4 6.10b 1.08·G + 1.35·Q (governing): moment M | 31.8 kNm | 31.82 kNm | +0.06 % | |
| BC4 6.10b 1.08·G + 1.35·Q (governing): shear force V | 30.7 kN | 30.67 kN | -0.10 % | |
| BC5 0.9·G + 1.35·Q: reaction R | 29.76 kN | 29.759 kN | -0.00 % | |
| BC5 0.9·G + 1.35·Q: moment M | 30.9 kNm | 30.88 kNm | -0.08 % | |
| BC5 0.9·G + 1.35·Q: shear force V | 29.8 kN | 29.76 kN | -0.14 % | |
| BC6 0.9·G + 1.35·ψ0·Q: reaction R | 14.63 kN | 14.632 kN | +0.02 % | |
| BC6 0.9·G + 1.35·ψ0·Q: moment M | 15.2 kNm | 15.18 kNm | -0.12 % | |
| BC6 0.9·G + 1.35·ψ0·Q: shear force V | 14.6 kN | 14.63 kN | +0.22 % |
2. Serviceability limit state: displacement and reaction per combination
| Quantity | Technosoft | StruCla | Difference | Note |
|---|---|---|---|---|
| BC7 characteristic G + Q: displacement | 8.4 mm | 8.38 mm | -0.29 % | |
| BC7 characteristic: reaction | 23.73 kN | 23.728 kN | -0.01 % | |
| BC8, BC10, BC12 permanent G: displacement | 1.78 mm | 1.784 mm | +0.21 % | |
| BC8, BC10, BC12 permanent: reaction | 5.05 kN | 5.053 kN | +0.07 % | |
| BC9 quasi-permanent G + 0.3·Q: displacement | 3.76 mm | 3.761 mm | +0.03 % | |
| BC9 quasi-permanent: reaction | 10.66 kN | 10.656 kN | -0.04 % | |
| BC11 frequent G + 0.5·Q: displacement | 5.1 mm | 5.08 mm | -0.40 % | |
| BC11 frequent: reaction | 14.39 kN | 14.391 kN | +0.01 % |
3. Section properties HEA 180 (Technosoft: catalogue values; StruCla: calculated from the nominal dimensions)
| Quantity | Technosoft | StruCla | Difference | Note |
|---|---|---|---|---|
| A | 4530 mm² | 4526.6 mm² | -0.07 % | |
| I_y | 2.5100e+7 mm⁴ | 25110275.9 mm⁴ | +0.04 % | |
| I_z | 9.2500e+6 mm⁴ | 9246190.6 mm⁴ | -0.04 % | |
| W_el,y | 2.9360e+5 mm³ | 293687.4 mm³ | +0.03 % | |
| W_pl,y | 3.2480e+5 mm³ | 324957.2 mm³ | +0.05 % | |
| I_t | 1.4900e+5 mm⁴ | 150965.8 mm⁴ | +1.32 % | StruCla calculates I_t from the nominal dimensions |
| I_w | 6.0211e+10 mm⁶ | 60290363369.7 mm⁶ | +0.13 % |
4. Lateral torsional buckling (EN 1993-1-1 6.3.2.3), governing combination BC4 / 6.10b, no lateral restraint, load on the top flange
| Quantity | Technosoft | StruCla | Difference | Note |
|---|---|---|---|---|
| C1 (uniform load) | 1.130 - | 1.1270 - | -0.27 % | Technosoft 1.130, table value 1.127 |
| Elastic critical moment M_cr | 125.6 kNm | 124.26 kNm | -1.07 % | differs by the load height assumed for the top flange loading |
| Relative slenderness λ_rel,LT | 0.779 - | 0.7840 - | +0.64 % | |
| χ_LT (6.57), curve b | 0.828 - | 0.8259 - | -0.25 % | |
| Correction factor k_c | 0.940 - | 0.9400 - | +0.00 % | |
| Factor f | 0.970 - | 0.9700 - | +0.00 % | |
| χ_LT,mod (6.58) | 0.854 - | 0.8514 - | -0.30 % | |
| Buckling resistance M_b,Rd | 65.18 kNm | 65.020 kNm | -0.25 % | |
| Unity check, LTB (6.54), M_Ed = 31.8 kNm | 0.488 - | 0.4894 - | +0.28 % |
5. Cross-section checks
| Quantity | Technosoft | StruCla | Difference | Note |
|---|---|---|---|---|
| Shear at the supports V/V_pl,Rd (6.17) | 0.156 - | 0.1560 - | +0.03 % | |
| Bending at mid-span | 0.459 - | 0.4167 - | -9.22 % | Technosoft checks elastically (σ = 108 N/mm² / 235 = 0.459); StruCla uses the plastic resistance of this class 1 section (M/M_pl,Rd = 0.417), as EN 1993-1-1 6.2.5 allows |
6. What differs and why
- Factor 1.22 in 6.10a: Technosoft prints γG = 1.22 but calculates with KFI · 1.35 = 0.9 · 1.35 = 1.215 (BC1: 12.28 kN in total = 1.215 · 2.435 · 4.15). StruCla uses the rounded 1.22 of the Dutch NB table, so the two 6.10a combinations are 0.2 to 0.4 % higher. They do not govern; 6.10b (1.08, 1.35) is identical in both.
- Bending of the cross-section: Technosoft checks the class 1 section elastically (0.459), StruCla plastically (0.417), which EN 1993-1-1 6.2.5 allows. The check does not govern; lateral torsional buckling does.
- Lateral torsional buckling: both programs use 6.3.2.3 for rolled sections with curve b and kc = 0.94 for a uniform load. Mcr differs by 1.1 % (124.3 against 125.6 kNm), which gives a unity check of 0.489 against 0.488.
- Section properties: Technosoft uses catalogue values, StruCla calculates them from the nominal dimensions (differences up to 1.3 %, for It); Iy and Iz differ by 0.04 and 0.04 %.
- Deflection criteria: the displacements are equal (table 2). The checks differ: Technosoft limits the frequent additional deflection to 0.002·L and the quasi-permanent final deflection to 0.004·L and multiplies by a second-order factor of 1.10; StruCla limits the characteristic deflection to L/250. The criteria are a project choice, so they are not compared here.
- Second order: both calculate first order for the forces; the 1.10 factor in Technosoft only applies to its deflection checks.