How to form exterior cip concrete stair with radius

[samdamon]

Gents-

I have a client who wants to install a cast-in-place concrete stair on grade on the exterior of a new restaurant addition. In plan, the stair is about 45 feet long, about 6' wide, and the nosing of each tread is to be formed in an arc with about a 42 foot radius. Its unusual.

Is it feasible to form stair treads in the field with such a radius?

 

[SlideRuleEra]

Yes, experienced formwork carpenters can work wonders with plyform. The problem is to find the carpenters with that experience level & to pay the price.

 

[fuchsjr]

I have used Azek material in the past to form stairs like that, that were wider than 8'. Makes a nice smooth finish with easy release from the concrete.