Arch bridge made of plywood

[Engineertopi]

I made a small bridge over our backyard ditch. An arch with such a large radius is pretty easy to bend by using regular hand tools. The beam dimensions are 55x150 mm and it has done in six 25 mm birch plywood plies. The span is 2.7 meters.

 

[Jameshow]

Why birch ply rather than oak or larch??

 

[Engineertopi]

Why birch ply rather than oak or larch??

To be honest, simply trying to empty my storage. This was a good project to use that thick plywood board. Birch is not optimal material for outdoor projects because small mold dots will appear really easily. The beams are saturated with wood oil to prevent that.
In Finland, basically we only have birch and softwood (spruce) plywood available.