Marina Bock | University of Wolverhampton (original) (raw)

Papers by Marina Bock

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Cold‐formed steel beams are often provided with web holes to accommodate service conduits. These ... more Cold‐formed steel beams are often provided with web holes to accommodate service conduits. These web holes result in reduced structural strength. Accurate estimation of the structural strength, including shear strength, is crucial during the design phase. There are a lot of studies available in the literature investigating the shear strength reduction in cold‐formed steel beams due to web holes. However, the experiments and parametric finite element results were not assessed against Eurocode 3 shear design provisions. Therefore, the shear design of cold‐formed steel beams with web holes is investigated herein. Existing experimental and parametric finite element analysis data on cold‐formed steel beams with circular web holes were collected from the literature. The accuracy of the current Eurocode 3 shear design provisions was then assessed using the collected data. The comparisons showed that the current Eurocode 3 shear design provisions were not suitable to estimate the shear stre...

Steel Construction, Feb 1, 2012

Journal of Constructional Steel Research

Journal of Structural Engineering

Energy and Buildings, 2019

Engineering Structures, 2017

Thin-Walled Structures, 2014

Web crippling is a local instability that causes cold-formed sections to become unstable when a c... more Web crippling is a local instability that causes cold-formed sections to become unstable when a concentrated load is applied transversally to the cross-section. The European design rules for stainless steels EN1993-1-4 [1] refers to the standards for carbon steel cold-formed sections EN1993-1-3 [2] to determine the web crippling ultimate capacity in which different expressions are presented according to the cross-sectional number of webs. For the fundamental case of hat sections (cross-sections with two or more webs), a single expression is codified which is in essence an empirical equation based on curve fitting given different coefficients. During the last years, research has been focused on improving this expression but overlooking the philosophy of a ?( ) strength curve in which are based most of the instability verifications of the European design provisions. Some background related to web crippling of stainless steel cross-sections can be found in [3] and [4]. The purpose of this paper is to assess if this slenderness-based approach is suitable to determine the ultimate resistance of stainless steel hat sections subjected to web crippling. The appraisal will be based on numerical simulations performed in Abaqus and experimental results found in the literature [5]. A comparison of the results with current design rules according to European [2] and American standards [6] is also presented. Two new expressions to predict web crippling strength of ferritic stainless steel hat sections are proposed in the present study.

Thin-Walled Structures, 2013

Journal of Constructional Steel Research, 2010

Journal of Constructional Steel Research, 2011

Journal of Constructional Steel Research, 2021

A significant amount of research has been reported on stainless steel tubular sections, while stu... more A significant amount of research has been reported on stainless steel tubular sections, while studies on I- and C-sections remain relatively limited. This paper presents a comprehensive numerical study on the response of stainless steel I- and C-sections subjected to minor axis bending, with outstand flanges subjected to stress gradients. Numerical models are developed and validated against reported test data on austenitic stainless steel sections under minor axis bending. Subsequently, parametric studies using standardised material properties on austenitic, duplex and ferritic stainless steel grades, covering a wide variety of cross-section slendernesses, are carried out to expand the structural performance data. The results are used to assess the applicability of the Eurocode slenderness limits, revealing that the Class limit 3 for outstand flanges under stress gradient is overly conservative. Moreover, Eurocode underestimates the predicted bending strengths, whereas the level of ...

The classical approach for the determination of cross-sectional resistance in stocky cross-sectio... more The classical approach for the determination of cross-sectional resistance in stocky cross-sections, based on section classification, underestimates real capacities, specially when non-linear metallic materials with high strain-hardening are considered. Alternatively, a more efficient design approach has been developed in the last few years: the Continuous Strength Method (CSM), based on the cross-section deformation capacity. The expressions for the determination of pure axial and bending capacities of cross-sections according to the CSM have been widely analysed.

This paper reports a numerical study on the optimisation of the lip size of Z-sections under grav... more This paper reports a numerical study on the optimisation of the lip size of Z-sections under gravity loads. Numerical models of cold-formed steel Z purlins restrained by cladding and angle struts and subjected to sagging moment were developed and validated against a total of 8 experimental results on Z-sections that failed in local or/and distortional buckling reported in the companion paper. Models of varying levels of complexity were generated and the key parameters affecting the structural response were determined by means of a sensitivity analysis. The investigated parameters included the magnitude, shape and combination of initial geometric imperfections pertinent to local and distortional buckling and the simplified or explicit modelling of test details such as struts and sheeting. Having determined the appropriate modelling strategy that leads to the best balance between accuracy and computational cost, parametric studies were conducted to investigate the effect of decreasing...

Structures

Abstract Eurocode (EC3) bending moment design model of mono-symmetric corrugated web girders (CWG... more Abstract Eurocode (EC3) bending moment design model of mono-symmetric corrugated web girders (CWGs) is based on the critical failure mode among the tension flange yielding, the compression flange yielding and the lateral-torsional buckling (LTB) of the compression flange. Recently, LTB behaviour of S460 laterally-unrestrained mono-symmetric CWGs with fully-effective flanges has been investigated by the authors, from which EC3 design model has been modified to better represent their actual strength. Nevertheless, the effect of the local buckling (LB) of slender compression flanges on the flexural strength and behaviour of such long girders has not been examined. While the corrugated web potentially makes large contribution to the out-of-plane stiffness, LB of the compression flange is expected to reduce LTB resistance of such girder significantly. Principally, this paper is devoted to exploring such effect on the accuracy of EC3 bending moment design model. Currently, virtual tests, by using ABAQUS software, are generated based on accurate validation. Then, parametric studies, intentionally designed to eliminate the tension flange yielding, are carried out on simply supported girders considering mainly the influences of the flange and web dimensions on the behaviour of S460 mono-symmetric CWGs. The strengths of such girders are compared with EC3 design model, from which it is found to provide unsuitable predictions. Hence, new formula has been proposed to accord better with the FE results. Additionally, several conclusions are provided at the end to assist design engineers in suggesting efficient cross-sections.