I've never heard confirmation of that.
I think everybody here just started believing its at the end because spideys most famous end battles take place at bridges. Although I do find it easy jump to this conclusion, I don't think so.
I think tte final battle will start in the highschool and then move on into the library then move into the sewers where the swat team turn into lizard people.
I could be wrong though. The set photos of captain stacy landing a helicopter down on the highschool (to presumably check up on a previous lizard and spidey battle in the school) and it appears to be daylight, and if capt stacy is going to die at the final battle then maybe my school-finale theory could be wrong.
Get me?