AISI S909
Full Name
AISI S909 – Test Standard for Determining the Web Crippling Strength of Cold-Formed Steel Flexural Members
Scope
AISI S909 is a standard test method developed by the American Iron and Steel Institute (AISI) to determine the web crippling strength of cold-formed steel flexural members. Web crippling is a localized failure mode that can occur in thin-walled steel members when concentrated loads or reactions are applied near supports or under concentrated loads. This failure is characterized by the buckling or yielding of the web in the vicinity of the applied load.
This standard applies to cold-formed steel flexural members, including beams, joists, purlins, and girts, made from sheet or strip steel with a yield strength up to 690 MPa (100 ksi). It covers various web crippling configurations, including:
- End bearing: concentrated load applied at the end of the member.
- Interior bearing: concentrated load applied at an interior location along the member span.
- Interior one-flange loading: concentrated load applied to one flange at an interior location.
The test procedure involves applying a concentrated load to the web of the test specimen through a bearing plate. The load is gradually increased until web crippling failure occurs. The failure load is then recorded and used to determine the web crippling strength of the member.
The test report should include the following information:
- Material properties of the steel (yield strength, tensile strength, elongation).
- Dimensions and geometry of the test specimen.
- Test setup and loading details.
- Failure load and mode of failure.
- Web crippling strength calculated according to the provisions of AISI S909.
AISI S909 provides a standardized method for evaluating the web crippling strength of cold-formed steel flexural members. The data obtained from these tests are essential for:
- Design: determining the appropriate web stiffener requirements and bearing lengths for cold-formed steel members.
- Specification: establishing performance criteria for cold-formed steel products.
- Quality control: ensuring the quality and consistency of cold-formed steel manufacturing processes.
AISI S909 Accredited Laboratory
Applied Testing & Geosciences, LLC is accredited for performing tests using the AISI S909 standard.
Contact us today to learn more about how we can support your testing needs.
Resources
Keywords
web crippling; cold-formed steel; flexural members; yield strength; ultimate strength; bracing; bearing stiffeners; web crippling strength; effective width; load bearing capacity; buckling; post-buckling behavior; section properties; material properties; failure modes