Separate the masses
Keep the bridge mass separate from the trolley and suspended load to avoid counting a component twice.
CRANE & SITE / TOOL 21
Bridge Crane Wheel Load Calculator
Estimate how trolley position transfers static load between the two runways before requesting certified wheel-load data.
Before you start: required inputs
- Use the crane general-arrangement drawing for runway support-line spacing and trolley transverse position.
- Obtain separate bridge, trolley/hoist and suspended masses, together with the wheel arrangement on each runway.
Calculation diagram
A PRACTICAL WALKTHROUGH
How to use this calculator
Locate the trolley
Measure its load line from the left runway support line across the bridge.
Review reactions and sharing
Read each runway reaction, then the ideal equally shared wheel loads for that side.
10 t lift near the left runway
THE INPUTS
20 m span, 15,000 kg bridge, 2,000 kg trolley, 10,000 kg suspended load, trolley 2 m from the left runway and two wheels per side.
THE RESULT
Left and right runway reactions are about 179.462 kN and 85.318 kN. Ideal left wheel load is 89.731 kN per wheel.
What does the result mean?
01
The largest ideal wheel load changes as the trolley moves across the span.
02
The two runway reactions add up to the complete entered static gravity load.
03
Equal sharing is a simplifying assumption. Actual end-carriage geometry, longitudinal eccentricity, dynamics and load combinations may increase individual wheel actions.
Watch for this
Using the complete crane mass as bridge mass and then adding the trolley mass again.
Formula & model conditions +
R_left = g[m_bridge/2 + (m_trolley + m_load)(L−x)/L]
R_right = g[m_bridge/2 + (m_trolley + m_load)x/L]
F_wheel = R_side / N_wheels
- Bridge centre of mass is at midspan. Trolley and payload act at the same transverse point.
- Each runway reaction is divided equally between the entered number of wheels.
- Longitudinal trolley eccentricity, actual end-carriage distribution, dynamics, skew, wind and load combinations are excluded.
Common questions
Can a runway supplier design directly from this output?
Request the crane supplier’s wheel loads, spacings, load combinations and horizontal actions. This model is a preliminary static comparison.
Why can wheels on one runway have different real loads?
Actual loads depend on longitudinal centres of gravity, end-carriage arrangement, stiffness and operating actions, which this transverse model omits.