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)

P48. Request Structures Advance Planning Study

An Advance Planning Study. (APS) is a preliminary study performed by the Division of Engineering Services, Structures Design. It includes structures recommendations, cost estimates and preliminary General Plans. The project engineer should make APS requests after concept geometrics have been established. An APS is required for all proposed projects where new structures or alteration of existing structures is anticipated.

Examples of new structure work includes:

  • New bridges
  • Non-standard retaining walls
  • Non-standard sound walls
  • Buildings
  • Pumping plants
  • Mechanically Stabilized Embankment (MSE) walls

Examples of alteration of existing structures includes:

  • Bridge widening or bridge rehabilitation
  • Seismic strengthening
  • Deck replacement
  • Widening to replace bridge railing
  • Extension or modification of box culverts spans greater than 6.1 meters
  • Scour mitigation
  • Building remodels
  • Bridge strengthening

APS requests are not required to obtain costs estimates for bridge approach slabs, deck treatments, bridge rail upgrade without widening, standard retaining or sound walls, standard culverts or for minor changes to standard retaining or sound walls.

The project engineer obtains an APS by submitting the “Request Form for DES Office of Structure Design”. The form is also referenced as the “Engineer’s Checklist for APS Request:” and is available on the Structures Design website. Prior to the APS Request, the project engineer should discuss the APS Request with the District Technical Liaison Engineer. If the structure work involves waterways, then the project engineer should also discuss the APS Request with the District Hydraulics Engineer. Along with an APS Request, the project engineer must provide all available supporting information that will assist the Structures project engineer in preparing the study. The project engineer should provide:

  • The proposed layout plan
  • Profile
  • Cross section
  • Top of wall elevation
  • Topography
  • Finish grade
  • As-built records
  • Traffic Handling (Stage Construction)
  • Construction constraints
  • And Utilities.

Inclusion of photos of the project site is also helpful. The project engineer should provide a Geo-technical Design Report for APS Requests for retaining walls or sound walls.

When requesting an APS, the project engineer should make careful consideration of potential constructibility issues. The project engineer must convey in the APS Request the vertical clearance and horizontal traffic clearances required during construction. Other constructibility issues that impact an APS include but are not limited to; constraints to falsework openings, construction staging, avoidance of buried or overhead utilities, flood flow, seasonal construction windows, swallows and bats, ADA compliant pedestrian paths, concrete curing and sensitive waterways, point discharge of rainfall runoff, signs on the structures, utilities that must be hung on or encased within the structure, and foundations.

Time Constraint:

Once an APS request is submitted, the project engineer should allow the following time frames for the various products:

APS Preparation
o Typical effort 3 to 4 months
o Hydraulic involvement 4 months
o Multiple alternatives 6 months minimum


Division of Engineering Services Structures Design website;

“Request Form for DES Office of Structure Design”


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This page last updated October 20, 2010