eTraxx wrote:.....I KNOW someone will point out that generally .. the board in forms didn't bulge and 'generally' .. cement didn't bulge between them.....
You are correct and they would be somewhat incorrect. The cement did sometimes bulge the form boards before we had 3/4" plywood readily available for forming right around WWII.
Before plywood, a construction grade dimensional lumber, not always T&G, was used and if the vertical bracing was insufficient, it would, at the least, bulge the boards, and at the worst, it would lead to blow-outs.
If you can find buildings built before that period, you will definitely see a lot of form lines and a few bulges. Even with today's methods of forming (a good example would be a poured-in-place parking garage), you can still spot areas where a bulge occurs because of improper design or installation of the forming system.
Your abutments done with this method will look great and give you some interesting weathering opportunities with those bulging joints.
I'll follow along to see how it turns out.
Gregory P. DeMayo
General Construction Superintendent Emeritus
St. Louis & Denver Railroad