BACKGROUND: AASHTO M 270 (ASTM A709), Standard Specification for Structural Steel for Bridges, covers the chemical, mechanical, and toughness properties of structural steel intended for use in bridges. The AASHTO/AWS D1.5 Bridge Welding Code covers the welding processes and requirements for welded highway bridges, but it does not address the toughness requirements for heat-affected zones (HAZs) of welded structural steel. Also, toughness requirements for HAZs of welded structural steel are not covered in AASHTO LRFD Bridge Design Specifications.
There is a need to identify the factors affecting the toughness for HAZs of welded structural steels used in highway bridges and determine what toughness requirements are necessary for incorporation in the AASHTO/AWS Bridge Welding Code and the AASHTO LRFD Bridge Design Specifications. This information will ensure that the HAZs will exhibit the toughness properties that are necessary for the intended performance and service life.
The objective of this research is to develop proposed toughness requirements for the heat-affected zones (HAZs) of welded structural steels for highway bridges. The research shall deal with steels intended for use in bridges as identified in AASHTO M 270, Standard Specification for Structural Steel for Bridges.
STATUS: Research on Phase I is comlplete. This research reviewed domestic and foreign literature, research findings, and other information relavent to the toughness of HAZs of welded structural steels and proposed a preliminary research plan for developing proposed toughness requirements for HAZs of welded structural steels for highway bridges. This information is available at
Further research will be performed under NCHRP Project 10-95A.