Good Bridge Design for Balsa Wood & Steel Blocks

[IGeekbot]

For our balsa wood bridge, 1/8 in square, would a bridge that crosses catilever and arch styles together work well? The steel blocks attached to the test table are acting like abutments, so all of our forces can be directed to them, right?

 

[Andrew Mason]

For our balsa wood bridge, 1/8 in square, would a bridge that crosses catilever and arch styles together work well? The steel blocks attached to the test table are acting like abutments, so all of our forces can be directed to them, right?

I think you will find that a combination of cantilever and arch design would work fine. They are just different methods of providing support for a bridge span. The arch will work for shorter spans (unless you want to build the arch above the bridge and suspend the road from it). You may want to post this in the engineering section.

AM

 

[hedons]

Here's a tip on building your bridge... I did this back in high school...

1. The joints are going to be the weak link.
2. Overlapping joints will be stronger than butt joints.
3. maximize the number of overlapping joints.
4. Since there are no restrictions on how you cut your balsa strips, consider that 1/8 x 1/8 balsa is equal to (4) 1/8 x 1/32 strips.
5. You can overlap the 1/8 x 1/32 strips like interlocking fingers to maximize the number of overlapped joints at a given intersection.

PS - The best bridges seemed to be traditional trusses rather than arches.