Shear Connector size/spacing Soldier Pile

[BurgoEng]

How exactly do you go about sizing the Shear Connector(stud) for the connection of concrete facing wall to a steel soldier pile? I have assumed it's based on the horizontal shear stress created by the soil load on the concrete wall, treating the conc like a simply supported slab, but the results I get are making me rethink.

I have calculated a Max Shear on the facing of about 11 kips at the support end (pile location) based on a uniform load of 1.4k/ft(soil pressure at bottom of 30' wall), 10' span and 1.6 load factor. Then, using Shear = VQ/I I get 1.4k/in. So, considering a 12" section of the wall, I get 17 k of horizontal shear force. That would require me to use 5/8"dia studs at 6" (9kip/stud) but that seems awfully high.

Am I missing something or just being WAY to conservative?

 

[PEinc]

For the many permanent tiedback walls I've designed, I always sized the shear studs for tension caused by the total lateral earth and surcharge pressures. I then sized the unreinforced concrete work pad to support the vertical weight of the concrete facing. For a 12" thick facing, usually a 2' wide, continuous, plain concrete pad is sufficient to accomodate a reasonable vertical load. Call me if you want to discuss this.