How to repair cement panel staircase?

[bob11]

Hello,

Appreciate advise on how to repair two steps. 

Two of the very heavy steps are just sitting there, unable to thread a nut on, the other is barely showing any thread. Moving a piano on a machine popped out the nut probably because of little thread and some rust.

* Could weld it in, but that’s only as good as the weld onto the bolt.

* drilling through the cement and the mental support for a new bolt - will I expect could break up the cement and hit any metal rods in the cement.

* only one I can think of 

remove the step 

bolt a metal panel 200 x 900 to the two metal existing supports 

bond the cement step to the metal panel with some type of adhesive that might exist that will be a permanent fix, my concern is if this would work 

problem I see is then we are raising the step a bit  compared to the others.

Thankyou for your advise