Upward deflection in simple beam mistake

[islam]

Hello,

I just have a question

On viewing a graphics for the deflection values of traffic load case. I found to values maximum and minimum and the maximum value is upward deflection but my bridge is a simple beam and i didn’t choose prestressing load case in these results so why i am getting upward deflection?

[asiloisad]

check the longitudinal forces effects. if they act higher than beam axis, then negative bending moment can occur = negative deflection (only if you set individual factors for vertical and longitudinal forces).