Using Soft Metric Reinforcing Bars in ... - Page 8

METRIC DESIGN AND CONSTRUCTION DOCUMENTS
Building Construction Projects. In November 1995, the American Concrete Institute issued a new edition of its 318 Metric Building Code. The title and designation of the document is "Building Code Requirements for Structural Concrete (ACI 318M-95)". The new edition of the ACI Code incorporates the soft metric bar sizes and metric Grades 300, 420 and 520 which are included in the current ASTM Specifications A615/A615M-96a and A706/A706M-96b. Thus, metric reinforcing bars for metric building construction projects, which are required to conform to the 1995 ACI Metric Code, will be in harmony with the industry's initiative toward production of only soft metric bars.

Transportation Construction Projects. In their planning for metric conversion, State Departments of Transportation (DOT's), have prepared in-house metric documents for design and construction.

The body of the current AASHTO Standard Specifications for Highway Bridges, 16th Ed., 1996, is presented in inch-pound units. Metric equivalents of the design expressions are included in an appendix for Division I - Design. In 1994, AASHTO issued a second design document titled LRFD Bridge Design Specifications. Two separate versions of the LRFD Specifications were published - a metric version and an inch-pound version. The LRFD document is intended to eventually replace the existing standard specifications. (LRFD stands for Load and Resistance Factor Design.)

The AASHTO (material) specification for metric billet-steel reinforcing bars is designated as M31M. AASHTO M31M is the counterpart of ASTM A615M. The current edition of M31M, which is dated 1994, does not reflect the soft metric bar sizes in the current A615M Specification. There is no counterpart AASHTO specification for ASTM A706M. In the interim for transportation construction projects, soft metric billet-steel rebars should be specified to conform to ASTM A615M-96a. Soft metric low-alloy steel rebars can be specified to conform to ASTM A706M-96b.

CLOSING COMMENTS
This report has focused on using soft metric rebars in non-metric construction projects. Since soft metric bars are physically the same as corresponding inch-pound bar sizes, the use of soft metric bars does not require changes in the original design nor changes in fabrication and construction practices.

RESOURCE DOCUMENTS
ASTM E380-92, "Standard Practice for Use of the international System of Units (Sl) (the Modernized Metric System)", American Society for Testing and Materials, West Conshohocken, Pennsylvania.

ASTM A615/A615M-96a, "Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement", American Society for Testing and Materials.

ASTM A706/A706M-96b, "Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement", American Society for Testing and Materials.

ASTM A6/A6M-96, "Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling", American Society for Testing and Materials.

"Building Code Requirements for Structural Concrete (ACI 318M-95) and Commentary-ACI 318RM-95", American Concrete Institute, Farmington Hills, Michigan.

"Standard Specifications for Structural Concrete (ACI 30196)", American Concrete Institute.

ANSI/AWS D1,4-92, "Structural Welding Code - Reinforcing Steel", American Welding Society, Miami, Florida.

"Standard Specifications for Highway Bridges", 16th Edition, 1996, American Association of State Highway and Transportation Officials, Washington, D.C.

"AASHTO LRFD Bridge Design Specifications", 1st Edition, 1994, and 1996 Interim, American Association of State Highway and Transportation Officials.

This publication is intended for the use of professionals competent to evaluate the significance and limitations of its contents and who will accept responsibility for the application of the material it contains. The Concrete Reinforcing Steel Institute reports the foregoing material as a matter of information and, therefore, disclaims any and all responsibility for application of the stated principles or for the accuracy of the sources other than material developed by the Institute.