expansion joint in concrete

huangyhg

expansion joint in concrete
i am designing a 140 foot long concrete screen wall that is only about 4 feet above ground and then another 4 feet below ground (below frost).  do i need to put any vertical expansion joints in this wall?  (meaning a joint through the thickness of the wall) maybe every 40 feet?  is this a bit excessive, or can i just do control joints to try to control cracking?
you might want to do an expansion/contraction analysis based on you particular temperature swings.  based on the 4' frost, i assume you get pretty @#$% cold in the winter.  limit the expansion joint spacing to no more than you are willing to tolerate architecturally.  re  
you can have structural concrete about 300' without any expansion joint. provided, you provide adequate rebar for temp and shrinkage control and proper joint detail at the ends.
for concrete retaining walls in the midwest usa it is not uncommon to see expansion joints every 100 feet and control joints every 25 feet.
i use the same as jae.