arching action in a concrete wall

huangyhg

arching action in a concrete wall?
does anyone know if arching action will occur above a door opening in an un-reinforced concrete wall like it would in a solid masonry wall?
thanks
if you draw a 45 degree line from the corners of the openings will the lines intersect before they touch the next opening?  
if so, then yes.  there are some other considerations, but if you know what you're doing with masonry, you're fine.
i am assuming you only want to know this for design of a lintel?
sure.  just look at the mayan arch.  amrehein is a good backup for this concept too.  however, anyterial below the arch and above the doorway must be supported with a beam.
mike mccann
mccann engineering
be sure that there is sufficient wall width on either side of the opening to take the horizontal arch thrust.  this means that the section of wall on either side will act as an unreinforced shearwall (under vertical compression and with a horizontal thrust load at the top).