Circular stairs usually need a center support, but I wanted to have the center open, so I designed this one to cantilever from the wall, leaving a 3' open center.
To accurately form the wall and steps, I cut a dozen 5' -1/6's from 3/4"
Rotating same boards around the pipe gave us the riser forms to pour the actual steps onto the ramp.
Step 1: Sketchup plan
Bars to hold the steps had to be placed in this wall as it was built, so I needed to know exactly where to place them so each step would have a rebar in tension off the wall. By drawing this staircase in 3/d (sketchup) , I could place the bars exactly. The ramp/steps
We poured the ramp and steps 6 months after the wall was built.
Step 3: Landing and circular support beam
Half the beam was in the wall, and the half you see supports the floor.