Problem solving: an arched bridge

A few years ago I designed a production of A Tale of Cinderella, by George David Weiss, Will Severin, and W. A. Frankonis, which is a different spin on the classic tale, and set in Venice. Most of the action in the musical takes place in and around a piazza, but there are also interiors, side buildings, and a gondola. And, of course, being Venice, it had to have a bridge.

After doing a lot of research on the city and its bridges, I decided the show needed a bridge that looked and felt like a Venetian bridge, with its long and graceful curves. Since the stage was over forty feet wide, there was lots of room for it, so the bridge ended up having a clear span of just about twenty feet. Now the question became how to build it within our budget and time frame, considering the rest of the set was huge.

Bridge 1

With something like this, the first reaction is usually to look at theatrical scenery textbooks and see how someone else did it. However, in this case, I went back to how the real Venetian bridges were built. Those bridges have been in place for hundreds of years and are still structurally sound, mostly because of the secret: the arch. If anchored properly, an arch is an amazingly strong structure; in fact, some Roman structures built with arches are still standing after two thousand years and counting.

So we started with the design itself…

Cinderella bridge_1

… and broke it down to its basic shapes:

Cinderella bridge_2

The bridge was anchored at one end (near center stage) by the platforms, and at the offstage end by securing it to the stage floor. That little curb in front was there for cosmetic reasons, not structural.

Cinderella bridge_3

The basic structure consisted of three separate arches, each made of two layers of 3/4″ ply screwed together. The shop guys took their time laying out the first arch to make sure it was accurate and true, and then used it as a template for the other two. Between the arches were wood spacers to hold them in place. On top went two four-foot-wide platforms, securely screwed to the arches. The treads and risers went next, and finally the bottom was skinned with 1/8″ lauan. The main concern as it was getting built was to make it into a solid, tight, safe structure, each piece securely attached to something else to avoid any movement.

Once completed, that bridge was a very solid structure and a nice complement to the set. It went up reasonably fast and came down even faster, and we stayed within our budget.