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Node Influence Effects

Node Influence Effects can be defined here for use in an influence analysis. The effect of a moving load will be found for any of the following situations:

  • Displacement or rotation in the specified direction at an unrestrained node.
  • Reaction in the specified direction at a restrained node.

The total effect is the sum of the factored individual effects. Note that only the Effect columns in the Static Bridge Loads table will be affected in this way. The total effect is used to find the critical load pattern but the magnitude of the loads (and so of the moments and forces produced by analysing them) is independent of the effect factors.

Definition​

Name

The name from the first line with a given effect number is used to identify the effect. Names from subsequent lines with the same effect number are ignored.

Effect

The effect number will normally be the same as the line number, unless the user chooses to combine effects (for example to maximise the sum of the reactions from a series of supports on a single column).

Node

The node number where the effect is to calculated.

Factor

The effect to be calculated can be factored, but will normally be 1. Non-unity factors can be used to combine effects (e.g. to maximise the weighted average of a number of reactions), but note, this is an advanced feature.

Type

  • Displacement – nodal displacement will be optimized.
  • Force – reaction will be optimized.

Axis & Direction

The axis and direction relative to that axis to be used for calculation.

Note: As the number of analysis cases in the bridge analysis task depends on the influence effects, the editing of influence effects will be disabled if there is a bridge analysis task.