I'm planning/designing a 8x8x16 CMU retaining wall (2' high retaining + 2.5' high wall beyond retaining grade - no slope). There are 2 separate segments. One segment is 72' long, the other is 52' long with a 90 degree corner at 37'/15'. Location = Phoenix, AZ
Question #1: Local code does not require expansion joints. Does this seem correct? Even though my wall segments are less than 80', is there any advantage of having one of my control joints be an expansion joint?
Question #2: Local code requires control joints every 24'. So, on the 52' segment with 90 degree corner, can I get away with just 1 control joint? If I need to do 2, should I place the 2nd in the shorter 15' section. I know I need to keep control joints 8' from corners, and I'd basically in the middle of the 15' section.
i wouldn't place an expansion jnt either - not in az,,, control jnts are fine IF needed for code compliance,,, far's distance, ask your inspector,,, if it were me, i would it but i'm far from the last word
Expansion joints are for clay brickwork; movement joints are for cmu walls which are subject to initial shrinkage.
This is a low (16") and short (25ft) cmu wall which has cracked roughly in the middle. They might have got away without a joint if they'd have used a softer mortar.