Preliminary design, plan preparation & specifications

Find information on preliminary studies, planning criteria, structure type selection and aesthetic consideration. Also find guidance for preparation of bridge plans, specifications and estimates.

Design memorandum

Design memorandum are issued as interim updates to the Bridge Design Manual. Active design memorandums supersede the Bridge Design Manual contents and are currently enforced.

Related manual chapters 

Chapter 1 - General Information (PDF 1.0MB)  provides background, organizational information, roles and responsibilities and quality control procedures.
Chapter 2 - Preliminary Design (PDF 3.6MB) provides guidance and criteria for developing preliminary designs and plans.

Bridge Design Manual 

Complete Bridge design guidance is found in the Bridge Design Manual (M 23-50).

See all manuals and standards

Zero emission electric vehicle registrations in Washington

increased 192% between 2017 and 2021.

45 projects to improve freight rail structures and freight movement

were underway as of December 31, 2021.

Washington state leveraged $100,000 to secure $27 million

in funding for airport investments in Fiscal Year 2022.