Why the steel at mid section of a beam the steel at top fiber is more than bottom fiber?

I just had a quick look at your model. Members 2 and 5 and mid spans of continuous beams of 3.1 meter length. and The adjacent spans on both sides are 6.4 meter long. So it is obvious that for vertical loads (dead loads/live loads) the tension will mostly be on the top face of the beam for the middle span represented by those members. However, considering the envelope there would be some tension at the bottom from other load cases. I do not see why you need to change the local axis of the beam - but the local axis orientation of the beam is based on some definite laws and cannot be changed at well. I will not go into the details of the local axis orientation to keep it short for now.

I just had a quick look at your model. Members 2 and 5 and mid spans of continuous beams of 3.1 meter length. and The adjacent spans on both sides are 6.4 meter long. So it is obvious that for vertical loads (dead loads/live loads) the tension will mostly be on the top face of the beam for the middle span represented by those members. However, considering the envelope there would be some tension at the bottom from other load cases. I do not see why you need to change the local axis of the beam - but the local axis orientation of the beam is based on some definite laws and cannot be changed at well. I will not go into the details of the local axis orientation to keep it short for now.