AASHTO - M 270M/M 270
Standard Specification for Structural Steel for Bridges
|Publication Date:||1 January 2012|
This specification covers carbon and high-strength low-alloy steel structural shapes, plates, and bars and quenched and tempered alloy steel for structural plates intended for use in bridges. Nine grades are available in four yield strength levels as follows:
Grades 250 , 345 , 345S [50S], or 345W [50W] are also included in ASTM A 36/A 36M, A 572/A 572M, A 992/A 992M, A 588/A 588M, and A 514/A 514M. When the supplementary requirements of this specification are specified, they exceed the requirements of A 36/A 36M, A 572/A 572M, A 992/A 992M, A 588/A 588M, and A 514/A 514M.
Grades 345W [50W], HPS 345W [HPS 50W], HPS 485W [HPS 70W], and HPS 690W [HPS 100W] have enhanced atmospheric corrosion resistance (Section 13.1.2). Product availability is shown in Table 2.
Grade HPS 485W [HPS 70W] or HPS 690W [HPS 100W] shall not be substituted for Grade 250 , 345 , 345S [50S], 345W [50W], or HPS 345W [HPS 50W]. Grade 345W [50W] or HPS 345W [HPS 50W] shall not be substituted for Grade 250 , 345 , or 345S [50S] without agreement between the purchaser and supplier.
When the steel is to be welded, it is presupposed that a welding procedure suitable for the grade of steel and intended use or service will be utilized. See Appendix X3 of ASTM A 6/A 6M for information on weldability.
For structural products to be used as tension components
requiring notch toughness testing, standardized requirements are
provided in this standard. These requirements are based upon
American Association of State Highway and Transportation Officials
(AASHTO) requirements for both fracture-critical and
Supplementary requirements are available but shall apply only if specified in the purchase order.
The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system is to be used independently of the other, without combining values in any way.
For structural products cut from coiled product and furnished without heat-treatment or with stress relieving only, the additional requirements of ASTM A 6/A 6M, including additional testing requirements and the reporting of additional tests, apply.