Ústav kovových a dřevěných konstrukcí

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Welded beam-to-column steel joints: Assessment of European design rules
(Elsevier, 2024-03-30) Conde, Jorge; Freire, Fernando; Ljubinković, Filip; Vild, Martin; da Silva, Luís Simes
Properly validated high-quality Finite Element (FE) models with experimental tests permit an accurate description of the load-deformation path and stress state of steel joints and are nowadays accepted as “experimental results”. Changes to the design of welded joints in Eurocode 3 are currently proposed that affect the resistance and stiffness of the components associated with the column web panel. This paper presents an assessment of the design formulations included in the current Eurocode 3, part 1–8, and its forthcoming update in terms of stiffness and moment resistance, compared against a large parametric study of strong-axis beam-column welded joints for open sections carried out using validated sophisticated FE models. The results show that both the old and new Eurocode formulations provide a large scatter and no big differences between both methods. Additionally, the presence of axial force in the column shows a clear increase in the ratio between design resistance vs numerical resistance that, particularly in the case of transversally stiffened joints, may be unconservative.
Cast Screws as Shear Anchors for Composite Slabs
(Elsevier, 2017-07-20) Holomek, Josef; Bajer, Miroslav; Vild, Martin
Composite slabs consist of trapezoidal steel sheeting and concrete cover. The steel sheeting serves as both, a lost framework and a tension bearing member after hardening of concrete. The longitudinal shear between the sheeting and the concrete must be ensured by a mechanical interlock, for example shear studs or prepressed embossments in the sheeting. The traditional massive shear studs have to be welded to the supporting construction of the slab. Alternatively, thin screws can be drilled through the sheeting and cast into the concrete to ensure the composite action or to strengthen the composite slab in reconstructions locally. The usage of the screws is not limited to the steel supporting frames. This paper describes laboratory tests of the composite slabs with cast screws of various diameters and the effect of the screws on the bending capacity of the slab in combination with prepressed embossments.
Test Arrangement of Small-scale Shear Tests of Composite Slabs
(Elsevier, 2016-10-19) Holomek, Josef; Bajer, Miroslav; Vild, Martin
Composite slab consists of the layer of concrete above the trapezoidal sheeting. The sheeting serves as a lost formwork as well as a tension bearing member after the hardening of concrete. The interaction between the sheeting and the concrete is necessary for composite action and can be ensured by prepressed embossments in the sheeting. According to nowadays codes, full scale bending tests are required in the design of the new sheeting of this type of composite slabs. An alternative longitudinal shear tests of a small part of the slab have already been derived by many authors. However, the testing arrangement is not unified. The results of the shear tests can be influenced by the magnitude and the way of application of the clamping force, the loading speed, the interface conditions and others. This paper presents a proposal of the testing arrangement and the recommendations for the testing procedure of small-scale shear tests. The recommendations are posted based on the results of several series of performed laboratory tests.
Numerical and experimental verification of column web in transverse compression
(Elsevier, 2024-07-23) Balázs, Ivan; Pešek, Ondřej; Horáček, Martin; Vild, Martin
This paper focuses on the problem of steel members of open double symmetrical cross-sections in transverse compression. First, the problem is introduced with examples of its application in steel structures of buildings and followed by the overview of selected substantial literature resources and current design codes provisions. The essential part of the paper is a presentation of results of experimental tests and advanced numerical analysis of members subjected to selected cases of transverse compression. Where possible, the results are compared with resistances obtained using provisions in currently valid design codes for steel structures. The influence of selected parameters on the resistance in transverse compression is quantified within the evaluation with specific attention paid to plate buckling of the web. Based on data obtained from the experimental and numerical investigations, the most notable findings are summarized.
Stability of Thin-Walled Beams with Lateral Continuous Restraint
(Vysoká škola báňská - Technická univerzita Ostrava, 2015-07-03) Balázs, Ivan; Melcher, Jindřich
Metal beams of thin-walled cross-sections have been widely used in building industry as members of load-bearing structures. Their resistance is usually limited by lateral torsional buckling. It can be increased in case a beam is laterally supported by members of cladding or ceiling construction. The paper deals with possibilities of determination of critical load of thin-walled beams with lateral continuous restraint which is crucial for beam buckling resistance assessment.

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