Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For Students · Bridge Designer

Bridge Designer for a scaffold tower

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a scaffold tower live below — adjust the inputs and watch it respond, right in your browser.

Beam Deflection

open full solver →

Beam Deflection & BendingLive

Euler-Bernoulli beam theory

Controls

Presets

Span L (m)

Load P (kN)

Flexural rigidity EI (kN·m²)

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.

▶ Run in Python

Data Inspector

Max deflection1.30 mm

Max moment12.5 kN·m

Span/deflectionL/3840

Governing equation

δ = \frac{P L ^{3}}{48 E I} = \frac{10 \cdot 5 ^{3}}{48 \cdot 20000} = 1.30 mm

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

open full solver →

Shear & Moment DiagramsLive

simply-supported beam

Controls

Presets

Span L (m)

Point load P (kN)

Load position a (m)

Uniform load w (kN/m)

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.

▶ Run in Python

Data Inspector

Reaction A28.3 kN

Reaction B21.7 kN

Max moment46.6 kN·m

at x2.01 m

Governing equation

\frac{d V}{d x} = - w = - 5, \frac{d M}{d x} = V, M_{m a x} = 46.6 kN\cdotm

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.

↓

Column Buckling

open full solver →

Column Buckling (Euler)Live

critical load & slenderness

Controls

Presets

Young's modulus E (GPa)

Moment of inertia I (10⁶ mm⁴)

Length L (m)

Cross-section area (mm²)

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.

▶ Run in Python

Data Inspector

Critical load Pcr2193 kN

Effective length3.00 m

Slenderness KL/r52

Critical stress731 MPa

Governing equation

P_{cr} = \frac{π ^{2} E I}{( K L ) ^{2}} = \frac{π ^{2} ( 200 GPa ) ( 10 \times 1 0 ^{6} mm ^{4} )}{( 1 \times 3 m ) ^{2}} = 2193 kN

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.

↓

Concrete Beam

open full solver →

Reinforced Concrete BeamLive

flexural capacity (ACI)

Controls

Presets

Width b (mm)

Effective depth d (mm)

Steel area As (mm²)

Concrete f'c (MPa)

Steel fy (MPa)

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.

▶ Run in Python

Data Inspector

Stress block a82 mm

Nominal Mn289 kN·m

Design φMn260 kN·m

Behaviortension-controlled

Governing equation

a = \frac{A _{s} f _{y}}{0.85 f _{c}^{'} b} = 82 mm, M_{n} = A_{s} f_{y} (d - \frac{a}{2}) = 1500 \cdot 420 (500 - \frac{82}{2}) = 289 kN\cdotm

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

open full solver →

Soil Bearing Capacity (Terzaghi)Live

foundation design

Allowable bearing pressure

400kPa

Allowable load ≈ 801 kN per metre of footing

Controls

Presets

Cohesion c (kPa)

Friction angle φ (°)

Unit weight γ (kN/m³)

Footing width B (m)

Embedment depth (m)

Factor of safety

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.

▶ Run in Python

Data Inspector

Nc30.1

Nq18.4

Nγ22.4

Ultimate qult1201 kPa

Governing equation

q_{u} = c N_{c} + γ D_{f} N_{q} + \frac{1}{2} γ B N_{γ} = 10 (30.1) + 27 (18.4) + \frac{1}{2} (18) (2) (22.4) = 1201 kPa

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.

↓

Base Shear

open full solver →

Seismic Base ShearLive

equivalent lateral force

Controls

Presets

Number of stories

Weight per floor (kN)

Design accel. SDS (g)

Response factor R

Importance factor I

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.

▶ Run in Python

Data Inspector

Seismic coeff. Cs0.150

Total weight W9,000 kN

Base shear V1350 kN

Roof force386 kN

Governing equation

V = C_{s} W = min (\frac{S _{D S} I}{R}, 0.15) W = 0.150 \times 9, 000 = 1350 kN

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.

or unlock everything with Pro →

Also for:Researchers Educators Engineers Hobbyists & Makers K-12 Students First Responders General version →

More with Bridge Designer

Bridge Designer for a cantilever balcony Bridge Designer for a bridge girder Bridge Designer for a floor joist Bridge Designer for a roof rafter Bridge Designer for a steel beam Bridge Designer for a timber deck Bridge Designer for a crane boom Bridge Designer for a retaining wall

Frequently asked questions

Is this good for students?: Yes — this version of "Bridge Designer for a scaffold tower" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.