| dc.description.abstract | As a result of the continuous development in steel production there are at the time several grades of high strength steels (HSS). Due to this increase in strength, structures are potentially designed slenderer than before. A problem which then comes of relevance is the buckling problem, as slender structures are more prone to buckling. The use of existing design codes is also limited to steel grades well below what is available.
This thesis aims to answer the research question: "Is it possible to define additional buckling curves, so that Eurocode 3 may also cover design against local buckling in cross-section class 4 of HSS beyond S800?". Through a literature study, theory on HSS, relevant design codes, and buckling is reviewed. The finite element method (FEM) is thereafter applied to investigate buckling behaviour of HSS of cross sections in class 4.
During the theory review, which covered necessary and central topics, it was also implied that Eurocode 3 and other design codes does not cover HSS to a sufficient degree. A FE-model is validated against literature that reported results from physical tests on welded S800 I-sections in class 4, subjected to compressional load.
This validated FE-model is further applied to investigate the local buckling behaviour in welded I-sections of class 4 and steel grades S800, S960 and S1100. In total, 114 analyses are performed, 34 for each steel grade, plus 12 for validation of the model.
It is observed that most of the results from the FE-analysis scatters around the existing buckling curves in Eurocode 3. However, there is also a number of results that deviates from this, for which the buckling curves in Eurocode 3 would overestimate the buckling capacity of the investigated specimens.
Based on the results from the analyses performed, two new buckling curves are suggested for designing class 4 I-sections. One modified version of curve d in Eurocode 3, and one new curve that covers local buckling of I-section where both flange and web are classified as class 4 sections. | en_US |
