Oweis Engineering Inc. (OEI) conducted a geotechnical study to support the design of an office building to be partially supported on a reclaimed slope. The slope had previously failed and the new condition was stabilized by partially effective tie-backs. The subsurface conditions consisted of fill over residual volcanic soil overlying weathered rock.

Foundation options considered were drilled shafts in sound rock or deep footings on weathered rock below residual soil. The rebuilt slope would be unstable under seismic conditions and additional reinforcements are necessary for stability. Closely spaced shafts were recommended as a stabilization option. Both static and seismic criteria were provided for structural design.