FROM: Bijan Khaleghi
DATE: September 26, 2006
SUBJECT: ASTM A 706 Reinforcement Requirement
TO: All Design Section Staff
The following revisions are made to the use of reinforcement for bridge construction:
- ASTM A 706 “Low Alloy Steel Deformed Bars for Concrete Reinforcement” shall be used for all cast-in-place concrete bridge reinforcement, including shafts and concrete piles, and for precast elements for bridge substructure. ASTM A 706 bars are more suitable for seismic applications, bar bending and welding.
- AASHTO M 31 “Deformed Carbon Steel Bars for Concrete Reinforcement”, grade 60, or ASTM A 706 bars may be used for following categories:
- Precast prestressed superstructure members
- Traffic barriers except for “S” bars
- Bridge approach slabs
- Standard Plan Retaining Walls, Noise Barrier walls and other walls
- Other minor roadside structures
The above revision is applicable to all bridge projects with AD Dates on or after January 2, 2007.
Section 9-07.2 of the WSDOT Standard Specifications will be updated to reflect the above revision.
ASTM A 706 specifications were developed for seismic applications. Limits are placed on yield and tensile strengths. Also, chemistry is controlled to facilitate welding. ASTM A 706 is available in sizes from #4 to #18. Coils of deformed bar meeting ASTM A 706 requirements are available in sizes from #3 to #6. Availability of ASTM A 706 reinforcing has improved locally, with only a modest price increase over AASHTO M 31.
All reinforcing bars specified in the Bridge Plans Barlist are considered to be ASTM A 706 bars. All other reinforcing bars specified in separate barlist in bridge plans such as precast members, traffic barriers, sidewalks, and bridge approach slabs could be either AASHTO M 31 or ASTM A 706 Steel.
If you have any questions regarding these issues, please contact Nate Brown at 705-7219 or Bijan Khaleghi at 705-7181.
F. Posner, Bridge and Structures – 47340
cc: Mohammad Sheikhizadeh, Bridge Construction - 47354