Seismic design for bridges & structures

Find seismic design and retrofit information for new and existing structures.

Related manual chapters

Chapter 4 - Seismic Design and Retrofit (PDF 4.7MB) provides guidance for expected bridge performance and post-earthquake service levels. This chapter details WSDOT additions and modifications to the AASHTO Guide Specifications for LRFD Seismic Bridge Design. It also includes design requirements for widening projects, retrofit projects and walls and buried structures.

Bridge Design Manual 

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

See all manuals and standards

Winter driving tips

Slow down on ice and snow.

It's easier to skid or lose control traveling at higher speeds. Give yourself more time to stop.

Carry chains, practice installing them.

Winter conditions could mean chains are required on your route. Practice putting them on your vehicle ahead of time.

Pack your winter car kit.

Carry extra supplies like warm clothing, ice scraper and brush, jumper cables and other emergency items.