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Bridge Designer for a steel beam

Simulate a steel beam live in your browser. This runs the real Bridge Designer solver — adjust the inputs, watch it respond instantly, and export the result. No install, no account.

1

Beam Deflection

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Beam Deflection & BendingLive

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Presets

Euler-Bernoulli theory relates a beam's deflection and internal moment to its load, span, and flexural rigidity EI. Deflection grows with the cube or fourth power of span, which is why doubling a span is far worse than doubling the load. Educational tool — not a substitute for a stamped structural design.

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Data Inspector

Max deflection1.30 mm
Max moment12.5 kN·m
Span/deflectionL/3840

Governing equation

Reading this result: At L/3840 this beam clears the usual L/360 serviceability limit, so strength (not deflection) is likely to govern the design.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

Shear & Moment DiagramsLive

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Presets

Shear and bending-moment diagrams show the internal forces along a beam. Shear jumps at each point load; the moment is the running integral of shear and peaks where shear crosses zero. Engineers size beams for this maximum moment. Educational tool, not a substitute for structural design.

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Data Inspector

Reaction A28.3 kN
Reaction B21.7 kN
Max moment46.6 kN·m
at x2.01 m

Governing equation

Reading this result: Combined loading: reactions RA=28.3 and RB=21.7 kN, and the maximum moment 46.6 kN·m lands at x=2.0 m where shear crosses zero.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

3

Column Buckling

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Column Buckling (Euler)Live

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Presets

A slender column fails not by crushing but by buckling sideways at the Euler critical load Pcr = π²EI/(KL)². The effective-length factor K depends on the end restraints — fixing both ends quadruples the capacity versus pinned. Educational tool, not a substitute for code-based design.

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Data Inspector

Critical load Pcr2193 kN
Effective length3.00 m
Slenderness KL/r52
Critical stress731 MPa

Governing equation

Reading this result: Intermediate slenderness (KL/r = 52): buckling and yielding compete, so design codes blend the two rather than trusting Euler alone.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

4

Concrete Beam

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Reinforced Concrete BeamLive

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Presets

A reinforced concrete beam resists bending through a compression block in the concrete and tension in the steel. Setting these forces equal gives the stress-block depth a, and the moment capacity Mn = As·fy·(d − a/2). A tension-controlled section (steel yields first) fails gradually — the ductile behavior codes require. Educational tool, not a design.

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Data Inspector

Stress block a82 mm
Nominal Mn289 kN·m
Design φMn260 kN·m
Behaviortension-controlled

Governing equation

Reading this result: Tension-controlled: with ρ ≈ 0.0100 well under 0.75·ρ_bal the steel yields first and the beam warns before it fails, while Mn = As·fy·(d − a/2) rises almost linearly with steel here.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

Soil Bearing Capacity (Terzaghi)Live
Allowable bearing pressure
400kPa
Allowable load ≈ 801 kN per metre of footing

Controls

Presets

Terzaghi's equation predicts the ultimate bearing capacity of a shallow footing as the sum of cohesion, surcharge, and self-weight terms, each with a bearing-capacity factor that grows sharply with the soil friction angle. Dividing by a factor of safety gives the allowable pressure. Educational tool, not a geotechnical design.

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Data Inspector

Nc30.1
Nq18.4
22.4
Ultimate qult1201 kPa

Governing equation

Reading this result: Mixed c-φ soil: all three terms contribute — deeper embedment and a wider footing both push the ultimate capacity higher.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

Seismic Base ShearLive

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Presets

The equivalent lateral force method estimates the total earthquake base shear as V = Cs·W, where the seismic coefficient Cs scales the design acceleration by the structure's ductility (R) and importance (I). The base shear is distributed up the building, concentrating force at the top. Educational tool, not a code design.

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Data Inspector

Seismic coeff. Cs0.150
Total weight W9,000 kN
Base shear V1350 kN
Roof force386 kN

Governing equation

Reading this result: Cs would be 0.167 but is capped at 0.15, so base shear is code-floored here — cutting R further will not add demand.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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About this simulation

The full Bridge Designer tool models a steel beam with the same numerics engineers and scientists use — running entirely client-side. Change any parameter and the result updates in real time, so you can build intuition, check a design, or teach the concept without spreadsheets or installs.

More you can do with Bridge Designer

Other ways to simulate a steel beam

Frequently asked questions

How do I simulate a steel beam?
Open this page and use the live Bridge Designer tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.
Is it free?
Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.
Can I use my own numbers?
Absolutely — every input is adjustable, and with data import you can drive a steel beam from your own measurements.