Restrained Retaining Wall

[Engineerbygut]

I am tasked with the design of a few bsmt walls retaining on the order of 10 feet of soil. I will require that the upper slab is in place before backfilling of walls (slab on deck supported by bar joists). After getting bearing pressure to work out, my footing sizes are becoming very large to get the 1.5 FS against sliding. I am considering that from corner to corner of walls retaining, perpendicular walls are present ~20 feet apart that restrain the ends of the wall. Taking the average demand across the wall vs worst case 1 ft strip results in a much less FS against sliding. There is a slab on grade over the footing but I do not think this helps my cause since there will be an expansion joint btw wall and slab. How do others handle this/feel about this?

 

[CJLCivilStruct]

As it's for a building, can the walls span laterally between return walls?

 

[HTURKAK]

I am considering that from corner to corner of walls retaining, perpendicular walls are present ~20 feet apart that restrain the ends of the wall. T

The return walls are 20 ft apart and the ht of BSMW 10 ft. In this case , cantilever action will govern.
I would consider temporary butressing of the BSMW with diagonal struts.

but I do not think this helps my cause since there will be an expansion joint btw wall and slab. How do others handle this/feel about this?

The EJ would receive premolded filler having certain bearing strength .You may model the top and bottom of BSMW simply supported.
The following sketch from the book FOUNDATIONS OF STRUCTURES ( By DUNHAM , 1960)

 

[XR250]

It is common to use the basement slab for restraint - even with an EJ. You actually do not need an expansion joint as the slab will shrink. Just use a thin bond breaker.