1967 Circa Concrete Details 2

[CASALA]

I've been asked to load rate a concrete structure that was constructed in 1967 and I have been provided with the structural drawings from the original design. However, the drawings indicate that the floor joists under consideration are 5x12+3@25". I am certain that the joist is 5" wide at the bottom and they are spaced at 25" o.c., but I am unclear as to how deep they are and what "12+3" means. If anyone is familiar with the call-out standards form the 1960s, please help me understand what is meant.

 

[rholder98]

My guess is that it's a 12" rib, plus a 3" slab, or a 15" overall joist.

 

[Lutfi]

I agree with rholder98.

See if you can get your hands on a CRSI manual for the early sixties. I assume that you know the concrete strength and the reinforcement in the ribs and the slab.


Regards,
Lutfi