Preliminary design, plan preparation & specifications for bridges & structures

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.

  • There are currently no design memorandums related to this topic

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

Slow down – lives are on the line. 

In 2023, speeding continued to be a top reason for work zone crashes.

Even one life lost is too many.

Fatal work zone crashes doubled in 2023 - Washington had 10 fatal work zone crashes on state roads.

It's in EVERYONE’S best interest.

95% of people hurt in work zones are drivers, their passengers or passing pedestrians, not just our road crews.