Question
I would like to know the difference between 'Lane Element' and 'Cross Beam' when applying moving loads.
Answer
If a lane is defined as a 'Lane Element', the distribution effect by transverse beams is not considered. To take into account the distribution of vehicle loads to girders through transverse beams, 'Cross Beams' should be selected.
In Moving Load Analysis, when defining the lane to be applied, the eccentricity and the wheel spacing for the lane element are defined, and the reference element for the lane definition should be selected.
If the 'Lane Element' is selected, both the vertical load and the moment due to the eccentricity of the vehicle are applied to the reference element. Even if the lane is located at the position of a cross beam, the distribution effect due to the cross beam is not considered if the lane is defined as a 'Lane Element'.
When selecting 'Cross Beam', the eccentricity is only used to determine the distance from the reference element to the lane. The vehicle load is distributed to the girder through the cross beams which are defined for the Cross Beam Group. Therefore, when modeling a bridge with multiple girders, it is recommended to use 'Cross Beam' as the lane definition element.