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Calcimator

Railroad Bridge Load Rating Calculator

Calculate Cooper E load rating for railroad bridges from member capacity, dead load, and live load effects per AREMA Chapter 15.

Inputs

ft
kips
kips
kips

Results

Cooper E rating

80.1

Rating factor (RF)1
Impact factor33.3%
Available capacity400 kips
Adequate for E801
Adequate for 286k cars1
Normal rating80.1 E
Operating rating104.1 E
Impact multiplier1.33
Fatigue concern level2
Max Gross Weight Tons160.1
Dl Ratio0.25%
How to Use This Calculator
  1. Enter Span length, Member capacity, and Dead load effect.
  2. Set Live load (E80) and Member type.
  3. Review the Cooper E rating result.
  4. Use Rating factor (RF) and Impact factor (%) to inform your decision.

How the result changes with Member capacity

Member capacityCooper E rating
1,009181.9
3,507681.8
6,5041,281.6
9,0011,781.3

What each input means

Span length
Bridge span length for impact factor calculation.
Member capacity
Ultimate or allowable capacity of the critical member.
Dead load effect
Force in the critical member from dead loads.
Live load (E80)
Force in the critical member from Cooper E80 loading (without impact).
Member type
0 = stringer, 1 = floorbeam, 2 = truss chord/diagonal.

What each result means

Cooper E rating
Bridge capacity expressed as Cooper E rating (E80 = full Class I standard).
Rating factor (RF)
Ratio of available capacity to demand. RF ≥ 1.0 means adequate for E80.
Impact factor
Dynamic load amplification per AREMA formula.
Available capacity
Member capacity minus dead load effect.
Adequate for E80
1 = bridge rates E80 or higher, 0 = deficient.
Adequate for 286k cars
1 = can carry 286,000 lb railcars (~E72), 0 = restricted.
Normal rating
Rating for regular unrestricted service.
Operating rating
Maximum permissible rating (restricted operations, ~130%).
Impact multiplier
1 + impact%/100 applied to live load.
Fatigue concern level
0 = low, 1 = moderate, 2 = high fatigue concern.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Span length = 60, Member capacity = 500, Dead load effect = 100, Live load (E80) = 300 = 5 input(s) provided
  2. Calculate Cooper E rating
    Cooper E rating = availableCapacity > 0
    80.1 = 80.1
  3. Calculate Rating factor
    Rating factor = availableCapacity > 0
    1.001 = 1.001
  4. Calculate Impact factor
    Impact factor
    33.3 = 33.3

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