https://www.um.edu.mt/library/oar/handle/123456789/1023 2026-04-27T23:10:43Z https://www.um.edu.mt/library/oar/handle/123456789/138742 Title: Behaviour, finite element modelling and design of flanged cruciform section steel columns Authors: Dai, Ruikai; Behzadi-Sofiani, Behnam; Buhagiar, Spiridione; Wadee, M. Ahmer; Gardner, Leroy Abstract: A study into the mechanical behaviour and design of flanged cruciform section steel members subjected to axial compression is presented herein. The mechanical behaviour of flanged cruciform section columns is first described, with particular emphasis on the newly developed approach for determining the elastic local buckling load for full flanged cruciform cross-sections. Existing experimental data on flanged cruciform section steel columns collected from the literature are then employed to validate numerical models developed within the finite element package ABAQUS. A comprehensive parametric study is subsequently conducted that encompasses a broad spectrum of cross-sectional geometries and global slenderness values. The mechanical behaviour and ultimate resistance of flanged cruciform section columns are shown to be dependent on not only the global slenderness, but also on the ratio of the elastic torsional to flexural buckling loads. The existing experimental data alongside the numerical parametric study results are employed to evaluate the resistance predictions provided in the current Eurocode 3 design codes, revealing a high degree of conservatism. Finally, a new design approach for flanged cruciform section columns, suitable for incorporation into future revisions of Eurocode 3, is proposed which provides significantly improved accuracy and consistency in resistance predictions compared with the current provisions. A reliability analysis of the proposed design approach is conducted in accordance with the EN 1990 procedure, resulting in a recommended partial safety factor . 2024-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/125731 Title: Blinding struts, part 2 : towards a simplified design method Authors: Vollum, R. L.; Izzuddin, B. A.; Munoz Abela, Jeanette Mireille; Potts, D. M. Abstract: The companion paper described how concrete blinding can be used to prop retaining walls in cut and cover excavations prior to the completion of the base slab. In addition, it was demonstrated that the behaviour of blinding struts can be accurately predicted with nonlinear finite element analysis (NLFEA) if the strut properties and ground profile are known. This paper presents a simple design-oriented analytical model which can be used for blinding struts as an alternative to NLFEA. The simplified model is shown to give comparable results to NLFEA and is attractive for design since it allows the effect of variations in imperfection amplitude and length to be rapidly assessed. A case study is presented which illustrates the use of the method and demonstrates that relatively thin blinding struts can resist the maximum axial forces likely to be encountered in cut and cover excavations. 2011-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/125729 Title: Blinding struts : part 1 : buckling response Authors: Munoz Abela, Jeanette Mireille; Vollum, R. L.; Izzuddin, B. A.; Potts, D. M. Abstract: The term ‘blinding’ is used to describe the thin layer of unreinforced over-site concrete which is used to protect the base of excavations from construction traffic and to provide a clean surface for the construction of the base slab. Blinding is not generally seen or exploited as a structural element even though it clearly provides some temporary lateral support to the retaining walls of cut-and-cover excavations. This paper shows that enhanced blinding can be used to prop retaining walls in cut-and-cover excavations during construction prior to the completion of the base slab. An experimental program is conducted on 1/4 scale specimens, which demonstrates that the failure load of blinding struts is governed by upheaval buckling, and which is employed for the validation of nonlinear finite element models. The main parameters governing the buckling load are shown to include: i) the amplitude of the geometrical imperfection, ii) the thickness of blinding, and iii) the eccentricity of the applied load with respect to the centroid of the strut. 2011-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/125726 Title: Local buckling of elliptical hollow sections under combined compression and bending Authors: Munoz Abela, Jeanette Mireille; Gardner, L. Abstract: The local buckling response of elliptical hollow sections is sensitive to the applied loading conditions due to the continuously varying curvature of the structural profile. Under pure compression and minor axis bending, local buckling initiates at the point of the maximum radius of curvature, while the introduction of major axis bending cause this point to migrate around the cross-section. In the present paper, the structural response of elliptical hollow sections under the most general loading condition of compression plus biaxial bending is considered. The elastic local buckling response is examined analytically, while ultimate capacity is investigated experimentally and numerically. Design recommendations are made on the basis of the findings. 2012-01-01T00:00:00Z