Verification
A connection program is only as good as its agreement with the published examples engineers already trust. Nexum is checked on every build against worked examples, closed-form solutions and code tables. The numbers below are from the current release; they are re-run automatically before every version.
Against published examples#
113 of 113 cases from books and codes pass within the stated tolerance (most within ±0.5–1%). A selection:
| Source | Examples covered |
|---|---|
| AISC Design Guide 1 (3rd ed.) | Base plate with axial load (required thickness, φfp,max), small and large moment (e_crit, bearing length Y, anchor tension), shear lug Example 4.7-5 (bearing, breakout, bending) |
| AISC Companion v15.1 (connections) | Tee shear II.A-30 (stem bolts, stem flexure, prying tmin, support bearing), single angle II.A-28A (eccentric support-side bolts with Table 10-11, angle shear, block shear and leg flexure), seated beams II.A-12A to II.A-15 |
| AISC Manual, Design Examples v16 | Shear tab II.A-17 (shear yielding and rupture, governing ratio 0.95), shear end plate II.A-11, flange plate moment connection II.B-1 (bolts, plate rupture and block shear, compression, column J10.1–J10.3, beam φMn with holes) |
| AISC 360-22 tables | Standard holes J3.3, edge distances J3.4, minimum fillets J2.4, pretension J3.1, J3.7 tension–shear, J3.8 slotted holes, B3.4b stiffness classification |
| AISC Design Guide 39 (2023) | Flush end plate Example 5.2-1 (Yp, required tp), thin plate with prying B.2-1, column flange stiffened and unstiffened 5.3-2 |
| AISC Design Guide 4 (2nd ed.) | 4ES Example 4.3 and 8ES Example 4.4 (Yp, Mnp, column flange Yc) |
| AISC Design Guide 24 | End tee 5.1, round slotted brace 5.2, beam over HSS 4.1, plates on HSS 7.1 and 7.2, truss joints 8.1, 8.4, 8.5 and 9.2, moments in branches (K3) |
| AISC/RCSC Design Guide 41 (2025) | Stainless bolts: tension–shear interaction, slip-critical duplex, bearing on a stainless web, double shear |
| Wight, Reinforced Concrete Mechanics and Design | Spread footing Example 15-2 (two-way shear, φvc, Mu at the face, development, bearing) and the ACI 318-19 one-way shear with ρw |
| ACI 318-19 Ch. 17 | Basic breakout Nb, pullout with heavy hex nut |
| IDEA StatiCa verification studies | Bolted wide-flange column splice (plates, block shear, slip-critical) |
| AISC Companion v15.1 | 35 member design examples (tension, compression, flexure, shear, combined, angles) |
| AISC Design Guide 29 | Uniform Force Method Examples 5.1–5.4 and equilibrium |
Against the AISC Manual tables#
1,540 tabulated values from the AISC Steel Construction Manual, 15th edition, transcribed page by page and compared one by one with what Nexum calculates, using the same functions the app uses. All of them agree: 1,475 to every digit the Manual prints, 53 within one unit of the last digit (rounded section properties), and 12 within 0.5% (the Manual multiplies values already rounded, such as Ab = 1.23 in² and φFnv = 20.3 ksi).
| Table | What it gives | Values |
|---|---|---|
| 4-1a | Available axial compression φcPn of W14 and W12 shapes, Fy = 50 ksi, Lc from 0 to 50 ft (E3, E7) | 1,182 |
| 7-1 | Bolt shear, Group A and B, threads included and excluded, single and double shear, A307, ⅝ to 1½ in | 80 |
| 7-2 | Bolt tension, Group A and B, A307 | 24 |
| 7-3 | Slip resistance, Class A surface, standard and oversized/short-slotted holes, Group A and B | 64 |
| 7-4 | Bearing and tearout per inch of thickness by bolt spacing, standard and oversized holes, Fu = 58 and 65 ksi | 94 |
| 7-5 | Bearing and tearout per inch of thickness by edge distance, standard, oversized and short-slotted holes | 96 |
Doing this found two errors, both now fixed: the oversized hole for a ⅝ in bolt was taken as 3/4 in instead of 13/16 in (Table J3.3), and the short-slot length used by one helper was ⅛ in too long. The tables also show where Nexum is more complete than the Manual: Table 4-1a gives flexural buckling about the y-axis only, while Nexum also checks torsional buckling (E4), which governs a short W12×65 by a hair (823 vs. 825 kips at 6 ft).
The finite element solver#
- Closed-form solutions: simply supported and clamped plates, membranes and cantilevers (Timoshenko) within 1%; a W18×50 cantilever deflection within 0.2%; an HSS 8×8×½ within 0.01%.
- Plasticity: uniaxial tension σ = Fy + H·εp within ±0.5%; a cantilever at 0.98·Pp converges, at 1.2·Pp the analysis stops as a mechanism.
- Buckling: a cantilever column and a plate with k = 4 within 0.4%.
- Equilibrium: pure axial compression reproduces P to 10⁻⁶; every joint model reports the global force balance.
- Consistency with the hand methods: for example, a base plate where DG1 gives 9.2 kip, the FE 31.6 kip and the plastic bound under the flange 50.3 kip — the FE sits between the two bounds, as it should.
- Against IDEA StatiCa: the shear tab and the base plate published studies are reproduced and the differences explained (see Base plates and anchors).
Robustness#
Two thousand random configurations are generated and calculated on every build: no invalid numbers, no exceptions, detailing rules respected, files validated. A separate campaign builds hundreds of designs exactly as the app would and checks that the scene, the drawing, Solutions and the FE model agree with each other.
What is not verified#
Each check tells you when something is a recommendation and not a code requirement, and when it could not be verified against a source. In particular, the anchorage chapter of the Mexican NTC has not been checked; anchors follow ACI 318-19.
The engineer of record remains responsible for the design. Nexum is a tool that makes every step visible so it can be reviewed.