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TO: All Design Section Staff
FROM: Chuck Ruth
DATE: February 5, 1996
SUBJECT: LFD Fatigue Criteria

Per my memo of March 2, 1994, the HS-25 Truck load should be considered as the "design truck" for all new WSDOT bridges. For steel bridges, the fatigue analysis should be completed using the HS-25 loading, not HS-20.

For all WSDOT steel girder bridges, assume Case I road type when determining the number of stress cycles for design (AASHTO Table 10.3.2A).

Save this memo in BDM Chapter 7 until AASHTO LRFD takes effect.


cc: M. M. Lwin, Bridge - 7340