Web-crippling Strength Of Cold-formed Steel Beams

The structural behavior of high-strength cold-formed steel beams subjected primarily to web crippling is investigated analytically and experimentally. Hat sections and I-beams, formed from five different types of high-strength sheet steels, are investigated under various loading conditions. In addition to the test data gathered in this phase of study, the experimental results obtained from the beam tests conducted at various companies are carefully evaluated. The evaluation indicates that the present available design criteria are not suitable for high-strength materials with yield strengths exceeding 80 ksi (552 MPa). New design formulas are derived for different types of loading conditions on the basis of available test data with material yield strengths ranging from 30 to 165 ksi (207 to 1,138 MPa). These empirical equations distinguish between web crippling failure caused by overstressing (bearing failure) and web buckling. Interaction formulas are derived for sections under combined web crippling and bending moment. The newly proposed design equations are verified by test results. © ASCE

Statistical evaluation of a new resistance model for cold-formed stainless steel cross-sections subjected to web crippling

This paper presents a statistical evaluation according to Annex D of EN 1990 (2002) of a new resistance function for web crippling design of cold-formed stainless steel cross-sections. This resistance function was derived by Bock et al. (2013) through the use of carefully validated numerical models with the aim to propose a design expression for stainless steel sections, which are currently designed following the provisions for cold-formed carbon steel sections given in EN 1993-1-3 (2006). Although it was shown that the proposed design equation is appropriate for application to various stainless steels, the statistical uncertainties in material properties that the different types of stainless steels exhibit require an assessment of various partial safety factors. The statistical assessment showed that the proposed resistance function by Bock et al. (2013) requires adjustment to satisfy the safety level set out in EN 1993-1-4 (2006); A recalibration is performed herein. The web crippling design provisions given in EN 1993-1-3 (2006) and SEI/ASCE 8-02 (2002) American standard for application to stainless steel are also statistically evaluated herein. Comparison with test and numerical data showed that the predictions of the recalibrated resistance function are better suited and consistent than existing design provisionsResearch Fund for Coal and Stee

Structural Behavior Of Members Consisting Of Curved Elements

A series of stub column tests have been performed in order to determine the initial buckling stress of curved elements with three supported edges and one longitudinal edge free. An empirical expression for the prediction of the elastic local buckling of this type of curved element has been developed and is compared to the test data. The tangent modulus concept is employed for the prediction of inelastic buckling. Also studied is the interaction between flat and curved elements when the flat element buckles before the adjoining curved element

Web Crippling Of Cold-formed Steel Beams Using High Strength Sheet Steels

The structural behavior of thin-walled cold-formed steel beam webs subjected to concentrated loads or reactions is discussed, with an emphasis on web crippling and a combination of web crippling and bending moment. This paper presents the results of tests carried out to determine the compressive strength of webs of cold-formed steel beams fabricated from high strength sheet steels commonly used in the automobile industry. Various conditions of loading arrangement were performed in this experimental study. Empirical expressions were derived to predict the ultimate web crippling loads. The new design criteria can be applied to cold-formed steel beams with material strengths up to 190, ksi