LRFD Analysis of Tension Drilled Shafts

[VoyageofDiscovery]

I have an underground box subject to large uplift among other loads.

When I model and analyse this box with actual loads and a client accepted factor for buoyance, it is stable without acounting for shaft-soil interface friction. However for the LRFD case it becomes unstable. I need to analyse this so I can design it structurally for the LRFD case. Can shaft perimeter friction be made into an equivalent spring along the length of the shaft? I also believe that the maximum stress would occur closer to the top of the shaft in the case of a homogenous soil strata, so I know it is not as simple as it appears from a geotechnical perspective. We have struck out belled configuration for quality of construction reasons.

 

[muuddfun]

Could you post a cross section showing the box and soil configuration?

 

[VoyageofDiscovery]

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