California Department of Transportation

Project Development Workflow Tasks (PDWT)

Part 3 - Identify Project Need and Project Initiation Document

II. Project Initiation Document

B. Develop Initial Alternatives (150.10) - Develop Concept Alternatives (WBS 150.10.15)

P41. Request Preliminary Geo-technical Design Report

Per Department policy, a Geo-technical Design Report must always be obtained for projects that include, but are not limited to,

  • Designs for cut slopes
  • Embankments
  • Earthwork
  • Landslide remediation
  • Retaining walls
  • Sound walls
  • Sign Structures (including CSM)
  • Groundwater studies
  • Basin (drainage and treatment)
  • Sub-excavations
  • Any other studies involving geo-technical engineering and engineering geology.

The project engineer obtains this information from Geo-technical Design Report. that is requested through the District Materials Engineer. Recommended maximum cut and fill slopes are key pieces of information that are provided by a Geo-technical Design Report. Earthwork quantities and cost estimates will be dramatically affected by these factors. Environmental impacts and right of way limits will also be greatly affected by slope recommendations. Specific information such as soil classification, permeability, erodibility, slope stability, depth to groundwater and ground water quality are technical factors that will be needed to support drainage basin design.

Typically, sufficient time and resources are not dedicated for obtaining a full Geo-technical Design Report during the PID phase. Therefore, the project engineer may obtain a Preliminary Geo-technical Design Report for cost estimating purposes. Preliminary recommendations may be based on prior test data taken in the project’s vicinity.

Any PID containing cost estimates based on a Preliminary Geo-technical Design Report should be clearly noted within the PID and the Risk Management Plan. The project engineer should state that the final Geo-technical Design Report and recommendations are required during the next phase (PA&ED or PS&E phase) of the project, and that preliminary cost estimates based on the Preliminary Geo-technical Design Report data must be revised.

When the PID delivery schedule, resources, and the number of project alternatives permit, the project engineer should request and obtain a final Geo-technical Design Report from the District Materials Office.

Time Constraint:

Obtaining a Preliminary Geotechnical Design Report. may take 4 to 6 months. The project engineer should consult with the District Materials Engineer for an anticipated wait time.


California Test Methods, (#130, “Geotechnical Design Reports and Materials Reports”)

HDM, (Chapter 100, Topic 113, “Geo-technical Design Reports”)

PDPM, (Chapter 3 Section 6, “Materials”)


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This page last updated October 20, 2010