PPolySim OS
For First Responders · Pedestrian Bridge Vibration

Pedestrian Bridge Vibration for a gantry crane

Built for first responders planning or training for real incidents. Run fast what-if scenarios for response planning and training — no software to install in the field. Simulate a gantry crane live below — adjust the inputs and watch it respond, right in your browser.

1

Beam Deflection

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Beam Deflection & BendingLive

Controls

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.

2

Standing Waves

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Standing Waves on a StringLive

Controls

A string fixed at both ends can only vibrate at its harmonics. Each mode n has n+1 nodes (pink) that stay still while the antinodes swing — the physics of every stringed instrument.

Presets

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Data Inspector

Harmonicn = 3
Frequency330 Hz
Nodes4
Antinodes3
Wavelength2L/3

Governing equation

Reading this result: 3 half-wavelengths fit the string, so there are 3 antinodes (max swing) and 4 nodes (fixed points). At harmonic n = 3 the string sings at 330 Hz — exactly 3× the 110 Hz fundamental, and the wavelength is 2L/3.

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

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More with Pedestrian Bridge Vibration

Frequently asked questions

Is this good for first responders?
Yes — this version of "Pedestrian Bridge Vibration for a gantry crane" is framed for first responders planning or training for real incidents. Run fast what-if scenarios for response planning and training — no software to install in the field.
Do I need to install anything?
No. It runs in any modern browser, free, with no account required.