Henry Ford Avenue Grade Separation, Port of Long Beach, CA
Henry Ford Avenue Grade Separation, Port of Long Beach, CA


Alameda Corridor Transportation Authority (ACTA)

Completion Date


DYA Client


Project Description

Diaz•Yourman & Associates (DYA) provided geotechnical and construction services for the non-bridge portions of a railroad-to-railroad grade separation at Henry Ford Avenue.  The project included mechanically stabilized earth walls up to 35 feet high, conventional cantilever walls to 10 feet high, roads, streets, highway on- and off-ramps, and pavement thickness designs.  Geotechnical concerns included tidally influenced high groundwater; highly liquefiable sandy layers and highly compressible clay layers; liquefaction-induced lateral spreading into adjacent flood control channels; liquefaction-induced settlement; and effects of embankments on adjacent facilities, which were supported on both shallow and deep foundations.  Several ground improvement techniques were considered.  Recommendations were provided for stone columns, vibro concrete columns, and a settlement isolation wall.

DYA developed an innovative design of a settlement isolation slurry wall to protect the existing adjacent Caltrans Bridge from settlement influence of the new embankment.  This unique approach allowed the structural engineers to replace some of the bridge approach spans with mechanically stabilized earth (MSE) embankments and saved more than $1 million.

V. R. Nadesh Nadeswaran, PE, GE – Geotechnical Manager (Design)

Christopher M. Diaz, PE, GE – Geotechnical Manager (Construction)

Allen M. Yourman, Jr., PE, GE – Geotechnical Principal

Gerald M. Diaz, PE, GE – QA/QC Reviewer

Our Services


  • Site and route evaluations
  • Geologic hazards
  • Seismic design
  • Site characterization
  • Subsurface drainage
  • Grading
  • Ground improvement
  • Slope stability
  • Foundations
  • Dynamic analyses
  • Pavements
  • Instrumentation


  • Material sources
  • Construction observation and testing
  • Verification of anticipated conditions
  • Evaluation of changed conditions
  • Foundation installation
  • Instrumentation
  • Claims evaluation


  • Site characterization
  • Remediation
  • Solid and liquid waste disposal
  • Landfill
  • Aerially Deposited Lead (ADL) Studies
  • Phase I Initial Site Assessments (ISA)
  • Phase II Hazardous Waste Studies
  • Sustainability


  • Forensic investigation
  • Litigation support

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