Thanks for all the advice. the reason I have the ladder thing there is because it was a bridge I built for my bike. I need the plywood on top because it is way too thin without it. the plywood would be 2 and a half feet wide whereas the bridge ladder thing is only 1 foot wide. But maybe if i just started from scratch on it I would spend less than the 25$ for the plywood... (the life of a cheapskate).
I was thinking to prevent the bridge from collapsing, maybe I could put a notch near the middle then just prop something under it like a chair or something similar and then i could be able to change the angle of the slope with different sized objects propping it up.
here are the non exploded views Frozen.
Thanks so much for all of your help, you guys are awesome!