Wheel Load Calculator

Compute max & min wheel loads for double-girder bridge cranes, plus static and fatigue verification against your rail and wheel specification. Based on GB/T 3811 and FEM 1.001.

GB/T 3811 FEM 1.001 Double-girder bridge Metric units Shareable URL

InputsEditable

Crane Parameters Geometry & mass

Rated capacity Q · t

Span L · m

Trolley weight G₁ · kg

Crane total weight G · kg

Hook minimum limit a · mm

Distance from rail centerline to hook at closest approach.

Trolley wheels n₁

pcs

Bridge wheels n · total

pcs

Total wheels across both end-trucks (end-beams).

Wheel & Rail Verification spec

Wheel diameter D · mm

Travel speed v · m/min

Rail type

b = 40 mm · r = 8 mm

Allowable pressure ratio k · N/mm²

Duty class M · C₂

Speed factor C₁ · auto

auto

Looked up from wheel Ø & travel speed.

Results

Pmax · Bridge wheel

--kN

Under loaded + trolley at closest hook

Pmin · Bridge wheel

--kN

Unloaded + trolley at far side

Trolley wheel — max(Q·9810 + G₁·9.81) / n₁ / 1000

Trolley wheel — minG₁·9.81 / n₁ / 1000

Equivalent fatigue loadP_eq = (Pmin + 2·Pmax) / 3

Allowable load — fatigue[P] = k·D·(b−2r)·C₁·C₂ / 1000

Allowable load — static[P]ₛ = 1.9·k·D·(b−2r) / 1000

PASS

Fatigue check — equivalent wheel load kN ≤ allowable kN.

PASS

Static check — Pmax kN ≤ allowable kN.

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How wheel load is applied

Maximum wheel load occurs on the side nearest the hook, when the trolley sits at the closest-approach position a. The formulas split the trolley + payload reaction across the bridge wheels of that rail, then add half the dead weight of the remaining bridge structure.

QRated hoisted mass — tonnes
GTotal crane weight — kg
G₁Trolley weight — kg
LBridge span — m
aHook minimum limit — mm
n, n₁Bridge / trolley wheel count
PmaxMax bridge wheel load — kN
PminMin bridge wheel load — kN

How this calculator works

Wheel loads determine runway beam sizing, column design and foundation anchors. Getting them right early saves structural rework later. This tool implements the formulas from GB/T 3811 (China) and their FEM 1.001 equivalents used across Europe.

Bridge wheel loads

Pmax = (Q·9810 + G₁·9.81) · (L·1000 − a) / (L·1000) / (n/2) / 1000 + (G·9.81 − G₁·9.81) / n / 1000 Pmin = G₁·9.81 · a / (L·1000) / (n/2) / 1000 + (G·9.81 − G₁·9.81) / n / 1000

The first term is the trolley + payload reaction at the near rail. The second term is half of the bridge's self-weight (excluding trolley) distributed across its wheels. Output is in kilonewtons.

Trolley wheel loads

Ptrolley,max = (Q·9810 + G₁·9.81) / n₁ / 1000 Ptrolley,min = G₁·9.81 / n₁ / 1000

Fatigue verification

The equivalent cyclic wheel load is compared to an allowable that accounts for wheel material, rail contact width, and duty class:

Peq = (Pmin + 2·Pmax) / 3 [P] = k · D · (b − 2r) · C₁ · C₂ / 1000

Pass criterion: P_eq ≤ [P].

Static strength verification

[P]static = 1.9 · k · D · (b − 2r) / 1000

Pass criterion: Pmax ≤ [P]_static. Both must pass for the wheel + rail combination to be acceptable.

Reference tables

Rail dimensions (b, r) — mm

Rail	b · face	r · radius
40 × 50	40	8
40 × 60	40	8
38 Kg/m	68	13
43 Kg/m	70	13
50 Kg/m	70	13
60 Kg/m	73	13
75 Kg/m	75	15
QU 70	70	6
QU 80	80	8
QU 100	100	8
QU 120	120	8

Duty class factor C₂ · GB/T 3811

Class	Examples	C₂
M1–M2	Hand / occasional	1.25
M3–M4	Light / regular	1.12
M5	Medium	1.00
M6	Heavy	0.90
M7–M8	Very heavy / continuous	0.80

Wheel Load Calculator

Crane Parameters Geometry & mass

Wheel & Rail Verification spec

Ready to spec this crane?

How wheel load is applied

How this calculator works

Bridge wheel loads

Trolley wheel loads

Fatigue verification

Static strength verification

Reference tables

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