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Bolt shear · J3.6
φrn = 0.75·Fnv·AbPass
= 0.75 · 54 ksi · 0.442 in²
= 17.9 kip / bolt
Base plate · anchors 81 %
UFM corner gusset
CBFEM · plastic strain
3D structure · every joint assembled
ETABS .e2k
Pass 90 %
AISC 360-22
εp 0.78 % ≤ 5 %

Design steel connections you can check by hand

AISC 360-22 checks and a CBFEM solver, with every formula, number and code section in view. Then the 3D structure, members, concrete and foundations around them.

Free account · 2 designs · no credit card

AISC 360-22AISC 341 · 358ACI 318-25AISI S100ASCE 7-22NTC 2023AWS D1.1

Connections first.
The whole job around them.

Design every connection you detail, and show how you checked it

  • 31 families: shear, moment, base plates, bracing, splices, HSS and full joints
  • Each limit state as a card: symbol, formula, your numbers, AISC section
  • Solutions ranks the cheapest change that passes and confirms it
Explore connections →
W14×132 · 2 beams · 4 bracesPass 81 %AISC 360-22 J4.3

A finite element model where the hand methods stop

  • Plates and member walls as shells; bolts, anchors and welds with their real stiffness
  • 5 % plastic strain criterion, buckling factor and M–φ stiffness
  • Runs next to the analytical checks, with the difference explained
How the CBFEM works →
CBFEM plastic strain on a welded moment connection εp 0.78 % ≤ 5 %Shells · bolts · welds · contact

Analyze the building and get every joint designed

  • Model like Revit or import the ETABS .e2k with loads and spectrum
  • Direct analysis, modal and response spectrum, verified against OpenSees
  • Every joint detected, grouped and assembled with its connection
Explore the 3D structure →
Moment frames · X · chevron · EBFETABS .e2k

Check members with the same transparency

  • AISC 360 Chapters D–H, deflection and torsion, with diagrams per station
  • AISI S100 cold-formed C, Z and back-to-back sections
  • Paste the ETABS frame forces and get one member per bar
Explore members →
Steel columnH1.1 · 46 %

Reinforced concrete columns and beams

  • Biaxial P–M interaction surface at any neutral axis angle
  • Beams in flexure, shear and torsion; slenderness
  • ACI 318-19, checked against StructurePoint examples
Explore concrete →
Reinforced concrete column cageMu/φMn 64 %

Footings and retaining walls, designed on the section

  • Spread footings with biaxial uplift and punching shear
  • Cantilever, basement and gravity walls with layered soil
  • Rankine, Coulomb and Mononobe-Okabe pressures
Explore foundations →
Retaining wall reinforcementSliding 74 %

Your own calculations, next to the program's

  • Rows with units: symbol = formula = substitution = result
  • Tables and sketches whose dimensions are variables
  • Inside each connection report, or on its own
Open the notebook →
Notebook
Shear tab · II.A-17

The only thing more important than moving fast
is getting the number right

Every build reproduces the published examples. If one fails, the release stops.

exact
1,653published values reproduced
AISC Design Examples · Manual tables
0.001 %against OpenSees on 3D frames
Direct analysis · second order
1,022automated tests every build
Checks · CBFEM · drawings
31connection families
2,091AISC shapes
113worked examples
See the published examples it reproduces
ExampleQuantityPublishedNexumΔ
AISC Design Guide 1 — axial base plateRequired plate thickness1.27 in1.27 in-0.1%
AISC Design Guide 1 — large momentAnchor rod tension Tu81.0 kip80.6 kip-0.5%
AISC Example II.A-17 — shear tabPlate shear rupture φRn52.2 kip52.2 kipexact
AISC Example II.B-1 — flange platesBolt shear, 8 × 7/8" A325-N194 kip195 kip+0.4%
AISC Example II.B-1 — flange platesColumn flange local bending (J10.1)171 kip171 kip+0.1%
AISC Design Guide 39 — Example 5.2-1Flush end plate, required tp0.519 in0.520 in+0.2%
AISC Design Guide 4 — Example 4.4 (8ES)Mnp without prying11,470 kip·in11,467 kip·inexact
AISC Example II.A-14 — stiffened seatStiffener weld φRn (Table 10-8)139 kip139 kip+0.3%
AISC Design Guide 24 — Example 8.5Gapped K joint, chord wall plastification415 kip415 kipexact
AISC Design Guide 1 — Example 4.7-5Shear lug concrete breakout φVcb26.1 kip26.1 kip-0.1%
AISC/RCSC Design Guide 41 — Example 2Stainless slip-critical joint, 8 bolts86.8 kip86.8 kipexact

Everything between
the model and the shop

Executive summary

Reports a checker can follow

By piece, with the governing combination and how each limit state fails.

Learn more
DXF 2010

Shop drawings and DXF

Sections, AWS weld symbols, bolt callouts and a bill of materials.

Learn more
Cheapest that passes

Solutions when it fails

Thicker plates, more bolts, ribs: ranked by cost, confirmed with the FE.

Learn more
ETABS .e2k

Bring your ETABS model

Grids, sections, loads, spectrum and combinations, ready to analyze.

Learn more
Parametric

A library that resizes itself

Typical connections that follow the members; save your company standards.

Learn more
AISC 341 · 358

Seismic by capacity

Prequalified RBS, WUF-W, end plates and BFP with their own checks.

Learn more

The connections you detail every week

Shear tab
ShearShear tab, angles, end plate, tee, seat
8ES end plate
MomentFlush, 4E, 4ES, 8ES, flange plates, CJP, AISC 358
Base plate with ribs
Column basesAnchors by groups, ribs, shear lug, ACI 318
UFM corner gusset
BracingGussets, UFM corner, chevron, X, EBF, rods
Overlapped K joint
HSS and trussesChapter K joints, plates on HSS, 2L trusses
Column joint
Full jointsFour beams and eight braces in one model

The connection platform for structural engineers

Analyze the building, and every joint arrives at its connection with its worst combinations, ready to check and to draw.

Explore the 3D structure

Everything in Nexum

One license opens what your plan includes. Your projects stay on your computer.

Steel connections

Shear, moment, base plates, bracing, splices, HSS and truss joints, full column joints.

CBFEM solver

Shells, bolts, anchors, welds and contact; plastic strain, buckling and stiffness.

3D structure

Direct analysis, modal, spectrum, drifts, joint detection, ETABS import and plans.

Solutions and optimizer

Cheapest change that passes, confirmed with the FE model.

Steel members

AISC 360 D–H, deflection, torsion; AISI S100 cold-formed.

Reinforced concrete

Biaxial columns and beams to ACI 318-19.

Foundations

Spread footings and retaining walls.

Notebook

Calculations with units, tables and live sketches.

Calculation report

By piece, with failure-mode figures and your logo.

Drawings and DXF

Sections, AWS symbols, DXF 2010, PDF and bill of materials.

Connection library

Parametric connections that resize with the members; company standards.

Seismic design

AISC 341 capacity design and AISC 358 prequalified connections.
Pricing

Start free. Upgrade when it pays.

The free account runs the full workflow on two designs. No trial clock, no credit card.

Monthly Yearly 2 months free

Free

Try the whole workflow on your own connection.

$0
forever
Sign up free

Includes:

  • 2 saved designs
  • Base plate, shear tab and end plate
  • Analytical and CBFEM checks
  • Report with watermark

Student

Everything to learn, with a university email.

$9 /month
academic use
Get Student

Everything in Free, plus:

  • 10 saved designs
  • All modules: 3D, members, concrete, foundations
  • Drawings, Solutions and seismic
  • Academic report

Basic

For offices that only need connection calculations.

$39 /month
billed monthly
Get Basic

Everything in Free, plus:

  • 10 saved designs
  • Every connection type
  • Full report without watermark
Best for engineers who design every week

Professional

The whole program, no limits.

$59 /month
billed monthly
Get Professional

Everything in Basic, plus:

  • Unlimited designs
  • 3D structure, members, concrete, foundations
  • Shop drawings, DXF and bill of materials
  • Solutions and optimizer
  • AISC 341 and 358 seismic
  • Your logo on the report · 2 computers
Only need one part? Add-on modules, $15/month each. Buy them alone or on top of Basic. Professional already includes all four.
3D structure Steel members Reinforced concrete Foundations
FeatureFreeStudentBasicProfessional
Design
Saved designs21010Unlimited
Connection types3 basicAllAllAll
CBFEM solver✓✓✓✓
Add-on modules ($15/month each)—IncludedOptionalIncluded
3D structure and ETABS import—✓—✓
Members, concrete, foundations—✓—✓
Solutions and optimizer—✓—✓
Seismic: AISC 341 and 358—✓—✓
Deliverables
Calculation reportWatermarkAcademicFullYour logo
Shop drawings, DXF, bill of materials—✓—✓
Account
Computers1112
Notebook✓✓✓✓

Prices in USD. Teams: Professional at $49 per user per month from 3 users, with a shared company library. Write to us.

Need help getting started?

Questions

Who is responsible for the design?

The engineer of record. Nexum makes every step visible so you can review it, and flags what is a code requirement, what is a recommendation and what could not be verified against a source.

Which codes does it use?

AISC 360-22 (LRFD), the AISC Manual and Design Guides 1, 4, 7, 24, 29, 39 and 41, AISC 341-22 and 358-22, ACI 318-25 or 318-19, AISI S100-16, and ASCE 7-22 or NTC 2023 load combinations.

How does the CBFEM compare to hand methods?

Nexum runs both. The analytical checks follow the Manual; the CBFEM model (plates, bolts, welds and contact, 5 % plastic strain) is verified against closed-form solutions and published studies, and tells you where it differs from the hand method and why.

Can I bring my ETABS model?

Yes. Import the .e2k with grids, sections, materials, walls, slabs, load patterns, spectrum and combinations. Nexum analyzes it, detects every joint and creates each connection with its governing forces.

Where are my projects stored?

On your computer: in the browser or as a file you save. Calculations run locally; the account only checks your plan.

Windows, Mac or browser?

Any modern browser on Windows or Mac. A Windows desktop app is on the way.

Try it on your next connection

Free account, the full workflow on two designs.