Thursday, July 26, 2007

Transmission of Concrete Wall Loads Through Slabs

Dear List,

ACI 318 Section 10.15 gives requirements for the transmission of column loads through floor systems, stating that if the column strength is not greater than 1.4 times the slab strength, no special provisions are required.  In Section 14.4, Section 10.15 is omitted from the list of sections applicable to "walls designed as compression members."

What happens when you have, say, an 8000 psi wall and a 6000 psi slab?  Can you pour the slab across the top of the wall, as you can for a column?  Or must 8000 psi concrete be puddled at the wall?  The ACI code does not seem to give direct guidance on this issue.  However, the concession that is made for columns (the 1.4 multiplier) is apparently not applied to walls, which leads one to believe that the wall must be continuous 8000 psi concrete.

Thanks in advance for your comments.

Best regards,
Daniel Popp