2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Assessment of Code Provisions for Strength Determination of Aluminum Structures by Testing

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Dr. Scott Walbridge, University of Waterloo (Presenter)
Mr. Laurent Gérin, University of Waterloo

Annex A14.1 of the CSA S6 Canadian Highway Bridge Design Code contains a formula and table for determining the design yield strength of unidentified structural steel by testing. The formula includes a 28 MPa correction for the difference between the “dynamic” and “static” yield strength. For aluminum structures, the American Aluminum Design Manual and the CSA S157 design code have similar formulas and tables for determining the ultimate strength of aluminum components by testing. The aluminum tables are believed to be inherently conservative in that they are established for a nominal aluminum strength based on a 99% survival probability, even though aluminum structures are then designed with a resistance factor that is the same as the one used for steel structures. CSA S6 Annex A14.1 and the associated resistance factors assume a 95% survival probability in establishing the nominal yield strength of the steel. Against this background, the proposed paper will present results of tension coupon tests used to investigate the existence of a difference between static and dynamic strength in aluminum using as-received and annealed samples of 5083 and 6061 alloy 9.5 mm thick plates. The results of these tests will be followed by a set of simple structural reliability analyses aimed at assessing the effects of the conservative assumptions made in the American Aluminum Design Manual and CSA S157. Given this information, a new formula and table will be proposed for establishing the strength of aluminum structures by testing.