shear connector sizespacing soldier pile
 

shear connector size/spacing soldier pile
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?
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.