The moving load calculation in Allplan Bridge allows for calculating the most unfavorable effects due to traffic. It is based on the theory of (related) influence lines allowing an easy and fast calculation.

First the influence lines are calculated by moving a unit force in the defined direction (vertical, transversal or longitudinal) along the corresponding lanes. In the second step the evaluation of the influence line is done by placing the load train such that the influence on the respective results becomes a maximum or minimum.

The final result of this is an envelope containing the most unfavorable effects. This lane related envelopes must be superimposed with each other to represent the total maxima and minima of the traffic load to be used for further design tasks.