TY  - JOUR
AU  - Dobrić, Jelena
AU  - Gluhović, Nina
AU  - Ivanović, Jovana
AU  - Rossi, Barbara
PY  - 2023
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3257
AB  - In this paper, the structural behaviour of cold-formed stainless steel (CFSS) built-up T- and cruciform-section columns is studied experimentally and numerically, and the effect of discrete fasteners on their flexural and torsional rigidity is considered. To build the singly symmetrical built-up T-section columns, two equal-leg angle sections made of lean-duplex grade EN 1.4162 were assembled back-to-back. The doubly symmetrical built-up cruciform-section columns were composed of four star-oriented equal-leg angle sections made of austenitic grade EN 1.4301. They were connected using M8 bolts of class 8.8. Two pin-ended built-up T-section columns with length of 1000 mm, and four built-up cruciform-section columns with lengths of 600 mm and 2400 mm with semi-rigid support conditions, were tested under pure axial compression. As observed in the tests, built-up T-section columns experienced flexural-torsional buckling failure, whereas built-up cruciform-section columns failed in torsional buckling mode. Finite element models were validated against the conducted experiments and used to perform a parametric study of the structural behaviour of CFSS built-up T- and cruciform-section columns. The study included the column length, cross-sectional dimensions and bolt spacing as variables. The experimental and numerical data, i.e., the column strengths and failure modes, were compared against the results obtained based on the European and North American Specifications alongside a recent method established for cold-formed carbon steel equivalents and based on the Direct Strength Method (DSM). It is shown that the DSM-based approach predicts the ultimate buckling resistances of the considered built-up columns more accurately than the available codified design methods.
PB  - Elsevier
T2  - Journal of Constructional Steel Research
T1  - Design procedures for cold-formed stainless steel built-up columns assembled from equal-leg angles
VL  - 212
DO  - 10.1016/j.jcsr.2023.108263
ER  - 

@article{
author = "Dobrić, Jelena and Gluhović, Nina and Ivanović, Jovana and Rossi, Barbara",
year = "2023",
abstract = "In this paper, the structural behaviour of cold-formed stainless steel (CFSS) built-up T- and cruciform-section columns is studied experimentally and numerically, and the effect of discrete fasteners on their flexural and torsional rigidity is considered. To build the singly symmetrical built-up T-section columns, two equal-leg angle sections made of lean-duplex grade EN 1.4162 were assembled back-to-back. The doubly symmetrical built-up cruciform-section columns were composed of four star-oriented equal-leg angle sections made of austenitic grade EN 1.4301. They were connected using M8 bolts of class 8.8. Two pin-ended built-up T-section columns with length of 1000 mm, and four built-up cruciform-section columns with lengths of 600 mm and 2400 mm with semi-rigid support conditions, were tested under pure axial compression. As observed in the tests, built-up T-section columns experienced flexural-torsional buckling failure, whereas built-up cruciform-section columns failed in torsional buckling mode. Finite element models were validated against the conducted experiments and used to perform a parametric study of the structural behaviour of CFSS built-up T- and cruciform-section columns. The study included the column length, cross-sectional dimensions and bolt spacing as variables. The experimental and numerical data, i.e., the column strengths and failure modes, were compared against the results obtained based on the European and North American Specifications alongside a recent method established for cold-formed carbon steel equivalents and based on the Direct Strength Method (DSM). It is shown that the DSM-based approach predicts the ultimate buckling resistances of the considered built-up columns more accurately than the available codified design methods.",
publisher = "Elsevier",
journal = "Journal of Constructional Steel Research",
title = "Design procedures for cold-formed stainless steel built-up columns assembled from equal-leg angles",
volume = "212",
doi = "10.1016/j.jcsr.2023.108263"
}

Dobrić, J., Gluhović, N., Ivanović, J.,& Rossi, B.. (2023). Design procedures for cold-formed stainless steel built-up columns assembled from equal-leg angles. in Journal of Constructional Steel Research
Elsevier., 212.
https://doi.org/10.1016/j.jcsr.2023.108263

Dobrić J, Gluhović N, Ivanović J, Rossi B. Design procedures for cold-formed stainless steel built-up columns assembled from equal-leg angles. in Journal of Constructional Steel Research. 2023;212.
doi:10.1016/j.jcsr.2023.108263 .

Dobrić, Jelena, Gluhović, Nina, Ivanović, Jovana, Rossi, Barbara, "Design procedures for cold-formed stainless steel built-up columns assembled from equal-leg angles" in Journal of Constructional Steel Research, 212 (2023),
https://doi.org/10.1016/j.jcsr.2023.108263 . .

TY  - JOUR
AU  - Dobrić, Jelena
AU  - Yancheng, Cai
AU  - Young, Ben
AU  - Rossi, Barbara
PY  - 2021
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2398
AB  - This study deals with the behaviour of duplex stainless steel bolted connections. The aim of the study is torespond to the question if the current stainless steel design specifications are able to predict the behaviourof such connections. Firstly, the net cross-section capacity of duplex stainless steel plates subjected to tensileloading are presented. They were conducted to obtain the stress–strain curves and tensile fracture behaviourused to support the finite element (FE) fracture simulations. Secondly, nonlinear FE models are developedfor duplex stainless steel bolted connections subjected to tensile loading. The FE models are validated againstexperimental data in terms of load–displacement curves, failure modes and ultimate loads. Then, a numericalparametric study that consists of 133 duplex stainless steel grade EN 1.4162 bolted connection specimens iscarried out. The failure modes of bolted connections are carefully examined, including combined tear out andbearing, bearing and net section, looking at the influence of parameters such as end distance, edge distance andspacing between the bolts in the connections. The results are compared to the design rules prescribed in thecurrent stainless steel design specifications. Generally, it is found that the Australian/New Zealand (AS/NZS),American (SEI/ASCE) Specification and European codes conservatively predict the ultimate strengths of thebolted connections, whereas the strengths predicted by the AS/NZS and SEI/ASCE specifications are overallmore accurate and less scattered.
T2  - Thin-Walled Structures
T1  - Behaviour of duplex stainless steel bolted connections
IS  - 169
DO  - 10.1016/j.tws.2021.108380
ER  - 

@article{
author = "Dobrić, Jelena and Yancheng, Cai and Young, Ben and Rossi, Barbara",
year = "2021",
abstract = "This study deals with the behaviour of duplex stainless steel bolted connections. The aim of the study is torespond to the question if the current stainless steel design specifications are able to predict the behaviourof such connections. Firstly, the net cross-section capacity of duplex stainless steel plates subjected to tensileloading are presented. They were conducted to obtain the stress–strain curves and tensile fracture behaviourused to support the finite element (FE) fracture simulations. Secondly, nonlinear FE models are developedfor duplex stainless steel bolted connections subjected to tensile loading. The FE models are validated againstexperimental data in terms of load–displacement curves, failure modes and ultimate loads. Then, a numericalparametric study that consists of 133 duplex stainless steel grade EN 1.4162 bolted connection specimens iscarried out. The failure modes of bolted connections are carefully examined, including combined tear out andbearing, bearing and net section, looking at the influence of parameters such as end distance, edge distance andspacing between the bolts in the connections. The results are compared to the design rules prescribed in thecurrent stainless steel design specifications. Generally, it is found that the Australian/New Zealand (AS/NZS),American (SEI/ASCE) Specification and European codes conservatively predict the ultimate strengths of thebolted connections, whereas the strengths predicted by the AS/NZS and SEI/ASCE specifications are overallmore accurate and less scattered.",
journal = "Thin-Walled Structures",
title = "Behaviour of duplex stainless steel bolted connections",
number = "169",
doi = "10.1016/j.tws.2021.108380"
}

Dobrić, J., Yancheng, C., Young, B.,& Rossi, B.. (2021). Behaviour of duplex stainless steel bolted connections. in Thin-Walled Structures(169).
https://doi.org/10.1016/j.tws.2021.108380

Dobrić J, Yancheng C, Young B, Rossi B. Behaviour of duplex stainless steel bolted connections. in Thin-Walled Structures. 2021;(169).
doi:10.1016/j.tws.2021.108380 .

Dobrić, Jelena, Yancheng, Cai, Young, Ben, Rossi, Barbara, "Behaviour of duplex stainless steel bolted connections" in Thin-Walled Structures, no. 169 (2021),
https://doi.org/10.1016/j.tws.2021.108380 . .

TY  - JOUR
AU  - Dobrić, Jelena
AU  - Filipović, Aljoša
AU  - Baddoo, Nancy
AU  - Buđevac, Dragan
AU  - Rossi, Barbara
PY  - 2021
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2394
AB  - This paper explores an attempt to investigate the structural behaviour and design of equal-leg stainless steel angle columns fabricated by the laser-welding of individual hot-rolled plates and by hot-rolling process. The studies cover columns with pin-ended boundary conditions exposed to pure axial compression. An advanced and realistic finite element model able to replicate the buckling features of stainless steel angle columns is developed and validated against available experiments collected in the literature. Employing the validated finite element model, quantitative numerical parametric studies, considering minor-axis flexural buckling, as well as flexural-torsional buckling, are performed. Based on comprehensive benchmark data, the accuracy, safety and applicability of the existing column design procedures provided in the European and North American structural stainless steel codes are assessed. The evaluation results reveal that the North American codified design procedures lead to conservative and scattered resistance predictions, thereby demonstrating a need for their improvement. As a result of conducted studies, the new criteria for design of pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns are proposed. Their suitability for inclusion in the European structural stainless steel design code is confirmed by statistical reliability analyses in accordance with EN 1990.
T2  - Thin-Walled Structures
T1  - Design criteria for pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns
IS  - 167
DO  - 10.1016/j.tws.2021.108175
ER  - 

@article{
author = "Dobrić, Jelena and Filipović, Aljoša and Baddoo, Nancy and Buđevac, Dragan and Rossi, Barbara",
year = "2021",
abstract = "This paper explores an attempt to investigate the structural behaviour and design of equal-leg stainless steel angle columns fabricated by the laser-welding of individual hot-rolled plates and by hot-rolling process. The studies cover columns with pin-ended boundary conditions exposed to pure axial compression. An advanced and realistic finite element model able to replicate the buckling features of stainless steel angle columns is developed and validated against available experiments collected in the literature. Employing the validated finite element model, quantitative numerical parametric studies, considering minor-axis flexural buckling, as well as flexural-torsional buckling, are performed. Based on comprehensive benchmark data, the accuracy, safety and applicability of the existing column design procedures provided in the European and North American structural stainless steel codes are assessed. The evaluation results reveal that the North American codified design procedures lead to conservative and scattered resistance predictions, thereby demonstrating a need for their improvement. As a result of conducted studies, the new criteria for design of pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns are proposed. Their suitability for inclusion in the European structural stainless steel design code is confirmed by statistical reliability analyses in accordance with EN 1990.",
journal = "Thin-Walled Structures",
title = "Design criteria for pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns",
number = "167",
doi = "10.1016/j.tws.2021.108175"
}

Dobrić, J., Filipović, A., Baddoo, N., Buđevac, D.,& Rossi, B.. (2021). Design criteria for pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns. in Thin-Walled Structures(167).
https://doi.org/10.1016/j.tws.2021.108175

Dobrić J, Filipović A, Baddoo N, Buđevac D, Rossi B. Design criteria for pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns. in Thin-Walled Structures. 2021;(167).
doi:10.1016/j.tws.2021.108175 .

Dobrić, Jelena, Filipović, Aljoša, Baddoo, Nancy, Buđevac, Dragan, Rossi, Barbara, "Design criteria for pin-ended hot-rolled and laser-welded stainless steel equal-leg angle columns" in Thin-Walled Structures, no. 167 (2021),
https://doi.org/10.1016/j.tws.2021.108175 . .

TY  - JOUR
AU  - Dobrić, Jelena
AU  - Ivanović, Jovana
AU  - Rossi, Barbara
PY  - 2020
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2098
AB  - In  this  paper,  the  structural  stability  of  cold-formed  stainless  steel  plain  channel  columns  under  axial compression is investigated. Reliable finite element models for channel section columns are first developed and validated  against  experiments  conducted  on  stainless  steel  lipped  channel  specimens.  This  is  followed  by  a parametric  study  in  which  columns  made  of  austenitic,  ferritic  and  duplex  stainless  steel  are  assessed.  The considered cross-section classes and column lengths cover the entire range of global slenderness. The effects of 
material and geometrical nonlinearity are considered in the numerical analysis. The numerically generated data are then employed to evaluate the accuracy of the current European and Australian design codes EN 1993-1-4 and AS/NZS  4673  respectively, for predicting the flexural and flexural-torsional column buckling resistance. The results show a necessity to improve the current buckling curve used to predict the flexural buckling resistance of plain channel section columns, currently adopted in EN 1993-1-4, whose use may lead to unsafe predictions, especially for the austenitic grade.
T2  - Thin-Walled Structures
T1  - Behaviour of stainless steel plain channel section columns
VL  - 148
DO  - https://doi.org/10.1016/j.tws.2020.106600
ER  - 

@article{
author = "Dobrić, Jelena and Ivanović, Jovana and Rossi, Barbara",
year = "2020",
abstract = "In  this  paper,  the  structural  stability  of  cold-formed  stainless  steel  plain  channel  columns  under  axial compression is investigated. Reliable finite element models for channel section columns are first developed and validated  against  experiments  conducted  on  stainless  steel  lipped  channel  specimens.  This  is  followed  by  a parametric  study  in  which  columns  made  of  austenitic,  ferritic  and  duplex  stainless  steel  are  assessed.  The considered cross-section classes and column lengths cover the entire range of global slenderness. The effects of 
material and geometrical nonlinearity are considered in the numerical analysis. The numerically generated data are then employed to evaluate the accuracy of the current European and Australian design codes EN 1993-1-4 and AS/NZS  4673  respectively, for predicting the flexural and flexural-torsional column buckling resistance. The results show a necessity to improve the current buckling curve used to predict the flexural buckling resistance of plain channel section columns, currently adopted in EN 1993-1-4, whose use may lead to unsafe predictions, especially for the austenitic grade.",
journal = "Thin-Walled Structures",
title = "Behaviour of stainless steel plain channel section columns",
volume = "148",
doi = "https://doi.org/10.1016/j.tws.2020.106600"
}

Dobrić, J., Ivanović, J.,& Rossi, B.. (2020). Behaviour of stainless steel plain channel section columns. in Thin-Walled Structures, 148.
https://doi.org/https://doi.org/10.1016/j.tws.2020.106600

Dobrić J, Ivanović J, Rossi B. Behaviour of stainless steel plain channel section columns. in Thin-Walled Structures. 2020;148.
doi:https://doi.org/10.1016/j.tws.2020.106600 .

Dobrić, Jelena, Ivanović, Jovana, Rossi, Barbara, "Behaviour of stainless steel plain channel section columns" in Thin-Walled Structures, 148 (2020),
https://doi.org/https://doi.org/10.1016/j.tws.2020.106600 . .

TY  - JOUR
AU  - Dobrić, Jelena
AU  - Rossi, Barbara
PY  - 2020
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2097
AB  - The strength of thin-walled stainless steel columns has been investigated extensively over the last few years. The present paper presents the results of an extensive computational study of the buckling strength of lipped–channel section columns made of austenitic, duplex, and ferritic grades. The numerically computed strengths together with the available experimental data collected in the literature are compared to the current European and Australian/New Zealand standard (AS/NZS) codified predictions over the whole slenderness range. Minor and major axis buckling as well as flexural-torsional buckling are considered. A reliability assessment in the sense of both standards is then performed. The safety factor γm and resistance factor ϕc are computed per family of stainless steel. In conclusion, we advise the use of different European buckling column curves rather than the one currently adopted in the code and to make a distinction between the families of stainless steel. Besides, seeing the very good agreement found against the AS/NZS guidance, we propose that the factor η, currently being a linear expression in the European standard, be replaced by the AS/NZS expression with the proposed parameters for each stainless steel family.
T2  - Journal  of  Structural  Engineering
T1  - Column Curves for Stainless Steel Lipped–Channel Sections
VL  - 146
DO  - 10.1061/(ASCE)ST.1943-541X.0002708
ER  - 

@article{
author = "Dobrić, Jelena and Rossi, Barbara",
year = "2020",
abstract = "The strength of thin-walled stainless steel columns has been investigated extensively over the last few years. The present paper presents the results of an extensive computational study of the buckling strength of lipped–channel section columns made of austenitic, duplex, and ferritic grades. The numerically computed strengths together with the available experimental data collected in the literature are compared to the current European and Australian/New Zealand standard (AS/NZS) codified predictions over the whole slenderness range. Minor and major axis buckling as well as flexural-torsional buckling are considered. A reliability assessment in the sense of both standards is then performed. The safety factor γm and resistance factor ϕc are computed per family of stainless steel. In conclusion, we advise the use of different European buckling column curves rather than the one currently adopted in the code and to make a distinction between the families of stainless steel. Besides, seeing the very good agreement found against the AS/NZS guidance, we propose that the factor η, currently being a linear expression in the European standard, be replaced by the AS/NZS expression with the proposed parameters for each stainless steel family.",
journal = "Journal  of  Structural  Engineering",
title = "Column Curves for Stainless Steel Lipped–Channel Sections",
volume = "146",
doi = "10.1061/(ASCE)ST.1943-541X.0002708"
}

Dobrić, J.,& Rossi, B.. (2020). Column Curves for Stainless Steel Lipped–Channel Sections. in Journal  of  Structural  Engineering, 146.
https://doi.org/10.1061/(ASCE)ST.1943-541X.0002708

Dobrić J, Rossi B. Column Curves for Stainless Steel Lipped–Channel Sections. in Journal  of  Structural  Engineering. 2020;146.
doi:10.1061/(ASCE)ST.1943-541X.0002708 .

Dobrić, Jelena, Rossi, Barbara, "Column Curves for Stainless Steel Lipped–Channel Sections" in Journal  of  Structural  Engineering, 146 (2020),
https://doi.org/10.1061/(ASCE)ST.1943-541X.0002708 . .

TY  - JOUR
AU  - Molkens, Tom
AU  - Dobrić, Jelena
AU  - Rossi, Barbara
PY  - 2019
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1772
AB  - The present paper deals with composite steel-concrete floor with headed shear studs welded onto a flat steel plate. In bridges applications, which are the focus of the paper, very thick steel plates are often combined with a moderate layer of concrete. And, in some wide slab applications, the most performant lay-out for the shear studs could lead to them being welded on top of an existing butt weld between steel plates. Presently, we are ignorant about the shear resistance of the weld-to-weld interface and its possible detrimental effect on the overall resistance of the system. In addition, the ultimate behaviour of the system combines the flexural resistance of a
composite cross-section followed by, when the concrete is cracked, the development of a compressed arch anchored in these headed shear studs, emphasising the importance of such connections. Both questions are addressed in the paper and, based on experiments, an in-depth analysis on the system’s behaviour at ultimate limit state is provided. Two types of tests are performed: pure shear tests complying to the push-out tests of Annex B of
EN 1994-1-1 and beam tests with four-point loading where the studs in the shear spans are loaded with longitudinal shear. For each pair of tests, the reference specimen was made with a steel plate without a butt weld or comprising a butt weld directly under the line of shear studs. Typical floor dimensions from bridge applications are studied. No difference in shear capacity, stiffness or failure mode could be observed. However, it was noticed that the classic design rules provided in EN1994-1-1 cannot accurately predict the failure load of the chosen configuration. Based on assumptions made following the observations of the failure mechanisms, the authors
propose a theoretical evaluation of the capacity of the system.
PB  - Elsevier Ltd.
T2  - Engineering Structures
T1  - Shear resistance of headed shear studs welded on welded plates in composite floors
EP  - 16
IS  - 109412
SP  - 1
VL  - 197
DO  - 10.1016/j.engstruct.2019.109412
ER  - 

@article{
author = "Molkens, Tom and Dobrić, Jelena and Rossi, Barbara",
year = "2019",
abstract = "The present paper deals with composite steel-concrete floor with headed shear studs welded onto a flat steel plate. In bridges applications, which are the focus of the paper, very thick steel plates are often combined with a moderate layer of concrete. And, in some wide slab applications, the most performant lay-out for the shear studs could lead to them being welded on top of an existing butt weld between steel plates. Presently, we are ignorant about the shear resistance of the weld-to-weld interface and its possible detrimental effect on the overall resistance of the system. In addition, the ultimate behaviour of the system combines the flexural resistance of a
composite cross-section followed by, when the concrete is cracked, the development of a compressed arch anchored in these headed shear studs, emphasising the importance of such connections. Both questions are addressed in the paper and, based on experiments, an in-depth analysis on the system’s behaviour at ultimate limit state is provided. Two types of tests are performed: pure shear tests complying to the push-out tests of Annex B of
EN 1994-1-1 and beam tests with four-point loading where the studs in the shear spans are loaded with longitudinal shear. For each pair of tests, the reference specimen was made with a steel plate without a butt weld or comprising a butt weld directly under the line of shear studs. Typical floor dimensions from bridge applications are studied. No difference in shear capacity, stiffness or failure mode could be observed. However, it was noticed that the classic design rules provided in EN1994-1-1 cannot accurately predict the failure load of the chosen configuration. Based on assumptions made following the observations of the failure mechanisms, the authors
propose a theoretical evaluation of the capacity of the system.",
publisher = "Elsevier Ltd.",
journal = "Engineering Structures",
title = "Shear resistance of headed shear studs welded on welded plates in composite floors",
pages = "16-1",
number = "109412",
volume = "197",
doi = "10.1016/j.engstruct.2019.109412"
}

Molkens, T., Dobrić, J.,& Rossi, B.. (2019). Shear resistance of headed shear studs welded on welded plates in composite floors. in Engineering Structures
Elsevier Ltd.., 197(109412), 1-16.
https://doi.org/10.1016/j.engstruct.2019.109412

Molkens T, Dobrić J, Rossi B. Shear resistance of headed shear studs welded on welded plates in composite floors. in Engineering Structures. 2019;197(109412):1-16.
doi:10.1016/j.engstruct.2019.109412 .

Molkens, Tom, Dobrić, Jelena, Rossi, Barbara, "Shear resistance of headed shear studs welded on welded plates in composite floors" in Engineering Structures, 197, no. 109412 (2019):1-16,
https://doi.org/10.1016/j.engstruct.2019.109412 . .