This is a recent project that required a different way of thinking about the problem. The previous design was one of mitered 6″ Dia pipe welded together to form a bridge. The new design is cantilevered and curves to allow close access for the wheel chair. Additionally all edges are rounded to mitigate any injury from impact by a unexpected motion of the chair.
More designs later.
Here are some animations that I have done to illustrate the possibilities with the use of AutoDesk Inventor
The first stage of this animation as to develop a model that would be the basis for the animation. Here is the beginning, the model created.