Soil Nail Design Optimization of 100 ft Deep Excavation Project in San Diego, CAÂ-Video

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Video Summary

Babak Mamakani of PB&A describes optimizing a 100-foot-deep soil nail wall for a residential development in San Diego. The project replaced existing buildings with a seven-story apartment complex, requiring a major slope cut and retaining wall. PB&A reviewed a previous design and optimized nail lengths, reinforcing-bar sizes, and facing thickness to balance nail tensile strength, facing resistance, and pullout resistance. The revised design used longer nails and thinner facing near the top, with shorter nails and stronger, thicker elements lower down. Compared with the original design, it reduced nail length by 44%, steel weight by 65%, and concrete volume by 23%, saving the client about $800,000 in construction costs. PB&A also used finite-element modeling to assess how the wall might affect a planned utility-tower foundation, identifying an acceptable placement area that met specified deflection and rotation limits. Construction was progressing as planned, with no observed movement.

Keywords

soil nail wall

retaining wall optimization

slope stabilization

finite element modeling

construction cost savings

utility tower foundation