Material properties and compressive local buckling response of high strength steel square and rectangular hollow sections

Abstract

An experimental investigation into the structural performance of compressed high strength steel (HSS) square and rectangular hollow sections is described in this paper. Both hot-rolled and cold-formed HSS sections were examined. In total six S460NH and five S690QH hot-rolled section sizes and three S500MC, two S700MC and four S960QC cold-formed section sizes were tested. The experimental programme comprised tensile coupon tests on flat and corner material, measurements of geometric imperfections, full cross-section tensile tests and stub column tests. The results of the experiments presented in this paper have been combined with other available test data on high strength steel sections, and used to assess the existing design guidelines for high strength steels given in Eurocode 3. The focus has been on the material ductility requirements, the Class 3 slenderness limit for internal elements in compression and the effective width formula for Class 4 internal elements in compression.Reliability assessments of the Class 3 slenderness limit (both the current value of 42 and a proposed value of 38) and the effective width formula for Class 4 internal elements in compression were carried out. The analysis indicated that, based on the assembled test data considered in this study, and the assumptions made regarding the statistical distributions of material and geometric properties, a partial safety factor greater than unity is required for HSS. Similar findings have also recently been presented for ordinary strength steels.

Flexural behaviour of hot-finished high strength steel square and rectangular hollow sections

“…Similar conservatism is also observed for the bending test results on the lower grade materials [45,51,52]. However, a stricter Class 3 limit of 38 was proposed in [49] for the case of ordinary carbon steel sections, based on the results of stub column tests; this limit was also shown to be suitable for high strength steels in [35]. Adoption of the proposed Class 3 limit of 38 is therefore supported in this study.…”

“…Similarly, the stricter Class 2 limit of 34 proposed in [49] was shown to be more suitable than the current codified limit of 38 for high strength steel internal elements in compression. Finally, while the current codified Class 3 limit of 42 was found to be applicable to high strength steel internal elements in compression on the basis of the presented bending tests, the results of stub column tests on high strength steel hollow sections in [35] revealed that a lower value of 38 [49] is more appropriate, and is therefore recommended herein. Overall, the behavioural trends exhibited by the examined high strength steel beams follow those observed for lower grades of material, and the results presented herein support the adoption of the revised slenderness limits proposed in [49] in Eurocode 3 for both normal and high strength steels.…”

“…The resulting material properties were used in the subsequent analysis of the bending test results and also in the development of the numerical models of the tested specimens. Full details of the material tests are reported in [35], while a summary of the test results is given herein in Table 3, showing tensile flat (TF), tensile corner (TC) and compressive flat (CF) coupon results. The material parameters reported in Table 3 are the Young's modulus E, the upper yield strength f y , the ultimate tensile strength f u , the tensile-to-yield stress ratio f u /f y , the strain at the ultimate tensile stress ε u , and the plastic strain at fracture ε f , based on elongation over the standard gauge length equal to 5.65 √ A c , where A c is the cross-sectional area of the coupon.…”

05.26: Reliability assessment for local buckling of plates

“…It can be seen that the deviation of the experimental results from the theoretical resistance increases with slenderness, while the tendency directs to more and more optimistic results. This could be also found for cold-formed sections [20]. Another observation is the generally better performance of the experiments conducted by the authors of this paper.…”

12.10: Structural response of high strength steel hollow sections under combined biaxial bending and compression

“…Hence, their suitability to HSS needs to be evaluated. Complementing the existing literature that investigates the structural performance of HSS [1][2][3][4][5][6], the present paper examines the structural behaviour of stub columns subjected to biaxial bending and compression that has been left relatively unexplored. Focus is placed upon the performance of S460 and S690 hot-finished square and rectangular hollow sections.…”