Influence Line Ordinate Calculator
Exact unit moving-load ordinates for simply supported beam reaction and a fixed section moment. Caller independently establishes units, regime, calibration and applicability; this does not establish design-code compliance, authenticity, operational safety, treatment efficacy or a validated forecast.
Description
An influence line describes response to a unit moving load.
An influence line describes response to a unit moving load.1
For a simply supported beam, reaction and section-moment ordinates depend on load and section positions within the span. Use this tool to calculate influence Line Ordinate from the supplied measurements and assumptions.
When to use Influence Line Ordinate Calculator
Use this tool to calculate influence Line Ordinate from the supplied measurements and assumptions. Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
How to use Influence Line Ordinate Calculator and understand its results
- Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
- Enter spanM, loadStationsM, sectionStationM, using the field meanings and rules below, then run the tool.
- Read leftReactionInfluence, sectionMomentInfluenceM. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| spanM | Span m | number | Required |
| loadStationsM | Load stations m | list of number | Required |
| sectionStationM | Section station m | number | Required |
Enter positive span in m, section coordinate within zero..span and load stations in the same inclusive interval. Return left-reaction ordinate 1−x/L and moment ordinate x(1−a/L) for x≤a, otherwise a(1−x/L). Ordinates are response per unit load; no moving-load train or envelope is evaluated.
reactionOrdinate=1−x/L; momentOrdinateM=x(1−a/L) if x≤a, else a(1−x/L) Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| leftReactionInfluence | Left Reaction Influence; follow the units, sign, ordering and evidence convention stated above | list of number |
| sectionMomentInfluenceM | Section Moment Influence M; follow the units, sign, ordering and evidence convention stated above | list of number |
{
"input": {
"spanM": 10,
"loadStationsM": [
0,
2,
10
],
"sectionStationM": 4
},
"output": {
"leftReactionInfluence": [
1,
0.8,
0
],
"sectionMomentInfluenceM": [
0,
1.2,
0
]
}
}Limitations and assumptions
For a simply supported beam, reaction and section-moment ordinates depend on load and section positions within the span. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Sheet Pile Bending Moment Calculator for this related task: A beam section trace integrates signed line loads into shear and bending moment.
Use Suspension Cable Tension Calculator when its separate inputs and assumptions fit the question: A parabolic cable model relates horizontal uniform load, span and sag to support tension.
References
-
Influence Line Ordinate Calculator — tool.io
Similar or alternative tools
- Sheet Pile Bending Moment Calculator
A beam section trace integrates signed line loads into shear and bending moment.
- Suspension Cable Tension Calculator
A parabolic cable model relates horizontal uniform load, span and sag to support tension.