Residential basement wall design??? 2

[daveh6729]

Can anyone explain to me why the newer codes (IBC in particular) completely neglect the design of the connection of the top of the basement wall to the floor framing system in order to prevent the wall from pushing inward at the top. In Michigan (where I live), everyone uses the 1/2" anchor bolt spacing from the wood section of the code...UBC used to have a chart for this connection, and even a connection of the joists to the sill plate depending on the wall height, and fill height...I wrote IBC about this, but they seem to not care...Meanwhile, builders use those cheap strap anchors, installed incorrectly, and I foresee lots of repair business for concrete wall repairs folks...especially in our area where clay soils are prevalent...

 

[JAE]

Would the IRC have the requirements that you state?

 

[sundale]

In 99.9% of the houses, the 1/2" diameter bolts at 6' o.c. with couple toenails connecting the joists to the sole plate seem to work just fine, in practice. They are way off numerically per NDS and I have probably seen less than a dozen examples of where the concrete wall top had been pushed inwards due to lateral soil pressures. It does happen though, and "the fix" usually entails costly helical pier tiebacks with steel channel strongbacks.

With a full basement, I detail the joists to have top flange hangers and put full depth blocking rows with extra nailing through the subfloor where the joists are parallel to the wall. I use a blocked diaphragm to transfer the compression force as a soldier brace across the building.

 

[PSlem]

The 2006 IRC adopted the varying anchor spacing depending on wall height.