Concrete Arch bridge project

Double track Concrete Arch Bridge

Cast from Hydrocal ( 75" long 14" high and weighing in at around 75  lbs.) August 2005 

This bridge was cast in a wooden mold and used 6  Five lb. cans of powdered hydrocal to cast the arches. The bridge deck is 3/4" plywood and is epoxyed to the top of the arches and then has 1/2" x 1/2" x 75" steel angle epoxyed and screwed to the underside of deck between the arches and also two   75" x 3/4" steel flat bar is glued and screwed to outside edges of deck to make sure there wasn't any flex to the bridge. Photos below show some of the process in making the bridge.

Here are the mold forms I used that I bought off ebay. I only had to make a new top and bottom of the arch form.

I used a door blank to screw down the mold to for casting.

Freshly poured hydrocal in mold

Form being taken off casting

Close up of casted arch

A shot taken of the bridge with some rolling stock on it

In place on the Layout