TY  - JOUR
AU  - Nikolić, Jelena
AU  - Tošić, Nikola
AU  - Murcia-Delso, Juan
AU  - Kostić, Svetlana
PY  - 2024
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3445
AB  - This paper summarises current research findings related to the behaviour and simulation of a relatively new type
of structural component: recycled aggregate concrete-filled steel tube columns (RACFST). The first part of the
paper presents a review of the latest experimental campaigns on RACFST columns subjected to a variety of
loading conditions. For each of loading condition, highlight observations about the behaviour of RACFST columns are presented. The second part of the paper provides a summary of numerical modelling approaches
developed for simulating the structural behaviour of RACFST columns. Special attention is paid to the selection
and calibration of material models for recycled aggregate concrete. Finally, directions for future investigations in
this area are outlined and discussed. The review will benefit researchers and professionals seeking to gain an indepth understanding of the behaviour of RACFST columns, and fills a gap in existing literature regarding a
number of practical issues related to the numerical modelling of these components.
PB  - Elsevier
T2  - Engineering Structures
T1  - Comprehensive review of the structural behaviour and numerical modelling of recycled aggregate concrete-filled steel tubes
VL  - 303
DO  - 10.1016/j.engstruct.2024.117514
ER  - 

@article{
author = "Nikolić, Jelena and Tošić, Nikola and Murcia-Delso, Juan and Kostić, Svetlana",
year = "2024",
abstract = "This paper summarises current research findings related to the behaviour and simulation of a relatively new type
of structural component: recycled aggregate concrete-filled steel tube columns (RACFST). The first part of the
paper presents a review of the latest experimental campaigns on RACFST columns subjected to a variety of
loading conditions. For each of loading condition, highlight observations about the behaviour of RACFST columns are presented. The second part of the paper provides a summary of numerical modelling approaches
developed for simulating the structural behaviour of RACFST columns. Special attention is paid to the selection
and calibration of material models for recycled aggregate concrete. Finally, directions for future investigations in
this area are outlined and discussed. The review will benefit researchers and professionals seeking to gain an indepth understanding of the behaviour of RACFST columns, and fills a gap in existing literature regarding a
number of practical issues related to the numerical modelling of these components.",
publisher = "Elsevier",
journal = "Engineering Structures",
title = "Comprehensive review of the structural behaviour and numerical modelling of recycled aggregate concrete-filled steel tubes",
volume = "303",
doi = "10.1016/j.engstruct.2024.117514"
}

Nikolić, J., Tošić, N., Murcia-Delso, J.,& Kostić, S.. (2024). Comprehensive review of the structural behaviour and numerical modelling of recycled aggregate concrete-filled steel tubes. in Engineering Structures
Elsevier., 303.
https://doi.org/10.1016/j.engstruct.2024.117514

Nikolić J, Tošić N, Murcia-Delso J, Kostić S. Comprehensive review of the structural behaviour and numerical modelling of recycled aggregate concrete-filled steel tubes. in Engineering Structures. 2024;303.
doi:10.1016/j.engstruct.2024.117514 .

Nikolić, Jelena, Tošić, Nikola, Murcia-Delso, Juan, Kostić, Svetlana, "Comprehensive review of the structural behaviour and numerical modelling of recycled aggregate concrete-filled steel tubes" in Engineering Structures, 303 (2024),
https://doi.org/10.1016/j.engstruct.2024.117514 . .

TY  - JOUR
AU  - Bursać, Milan
AU  - Kostić, Svetlana
PY  - 2024
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3489
AB  - The paper presents a nonlinear concentrated plasticity frame element for advanced analysis of steel frames exposed to elevated temperatures. The element extends the formulation based on the generalized plasticity material model that was successfully applied to the analysis of steel and composite structures. It considers the material's nonlinear behavior, temperature-induced loading, strength and stiffness degradation typical for structures under fire conditions. The nonlinear geometry is taken into account with the corotational formulation. Because of the generalized plasticity relations adoption, the element can describe the gradual yielding of cross sections. At the same time, the implemented return mapping algorithm ensures the element's high computational efficiency. The governing element equations, selection of parameters and computer implementation are discussed in the paper, followed by element validation through the number of experimental data examples and other numerical models. The comparative analysis demonstrated the element's versatility and capability to accurately predict the structural response of steel frame structures exposed to fire.
PB  - Elsevier
T2  - Computers and Structures
T1  - An efficient model for 3D analysis of steel frames exposed to fire
VL  - 297
DO  - 10.1016/j.compstruc.2024.107363
ER  - 

@article{
author = "Bursać, Milan and Kostić, Svetlana",
year = "2024",
abstract = "The paper presents a nonlinear concentrated plasticity frame element for advanced analysis of steel frames exposed to elevated temperatures. The element extends the formulation based on the generalized plasticity material model that was successfully applied to the analysis of steel and composite structures. It considers the material's nonlinear behavior, temperature-induced loading, strength and stiffness degradation typical for structures under fire conditions. The nonlinear geometry is taken into account with the corotational formulation. Because of the generalized plasticity relations adoption, the element can describe the gradual yielding of cross sections. At the same time, the implemented return mapping algorithm ensures the element's high computational efficiency. The governing element equations, selection of parameters and computer implementation are discussed in the paper, followed by element validation through the number of experimental data examples and other numerical models. The comparative analysis demonstrated the element's versatility and capability to accurately predict the structural response of steel frame structures exposed to fire.",
publisher = "Elsevier",
journal = "Computers and Structures",
title = "An efficient model for 3D analysis of steel frames exposed to fire",
volume = "297",
doi = "10.1016/j.compstruc.2024.107363"
}

Bursać, M.,& Kostić, S.. (2024). An efficient model for 3D analysis of steel frames exposed to fire. in Computers and Structures
Elsevier., 297.
https://doi.org/10.1016/j.compstruc.2024.107363

Bursać M, Kostić S. An efficient model for 3D analysis of steel frames exposed to fire. in Computers and Structures. 2024;297.
doi:10.1016/j.compstruc.2024.107363 .

Bursać, Milan, Kostić, Svetlana, "An efficient model for 3D analysis of steel frames exposed to fire" in Computers and Structures, 297 (2024),
https://doi.org/10.1016/j.compstruc.2024.107363 . .

TY  - JOUR
AU  - Đorđević, Filip
AU  - Kostić, Svetlana M.
PY  - 2023
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3107
AB  - In this study, two machine-learning algorithms based on the artificial neural network
(ANN) model are proposed to estimate the ultimate compressive strength of square
concrete-filled steel tubular columns. The development of such prognostic models is
achievable since an extensive set of experimental tests exist for these members. The
models are developed to use the simplest possible network architecture but attain
very high accuracy. A total dataset of 1022 specimens with 685 stub columns and 337
slender columns subjected to pure axial compression is collected from the available literature.
This is significant for the development of the initial model considering that for
this field it falls under the scope of big data analysis. The ANN models are validated by
comparison with experimental results. The validation study has shown the superiority
of surrogate models over the Eurocode 4 design code. The empirical equation derived
from the best-tuned Bayesian regularization algorithm shows a better agreement with
the experimental results than those obtained by the Levenberg–Marquardt algorithm,
and Eurocode 4 design code. A similar conclusion applies to stub and slender columns
independently. The Bayesian regularization-based model is negligibly slower than the
one developed on the Levenberg–Marquardt algorithm but gives a better generalization
even with simplified ANN. Generally, besides its high accuracy, one of the key
benefits of the presented ANN model is its applicability to a broader range of columns
than Eurocode 4 and other studies.
PB  - Springer
T2  - Journal of Big Data
T1  - Practical ANN prediction models for the axial capacity of square CFST columns
VL  - 10
DO  - 10.1186/s40537-023-00739-y
ER  - 

@article{
author = "Đorđević, Filip and Kostić, Svetlana M.",
year = "2023",
abstract = "In this study, two machine-learning algorithms based on the artificial neural network
(ANN) model are proposed to estimate the ultimate compressive strength of square
concrete-filled steel tubular columns. The development of such prognostic models is
achievable since an extensive set of experimental tests exist for these members. The
models are developed to use the simplest possible network architecture but attain
very high accuracy. A total dataset of 1022 specimens with 685 stub columns and 337
slender columns subjected to pure axial compression is collected from the available literature.
This is significant for the development of the initial model considering that for
this field it falls under the scope of big data analysis. The ANN models are validated by
comparison with experimental results. The validation study has shown the superiority
of surrogate models over the Eurocode 4 design code. The empirical equation derived
from the best-tuned Bayesian regularization algorithm shows a better agreement with
the experimental results than those obtained by the Levenberg–Marquardt algorithm,
and Eurocode 4 design code. A similar conclusion applies to stub and slender columns
independently. The Bayesian regularization-based model is negligibly slower than the
one developed on the Levenberg–Marquardt algorithm but gives a better generalization
even with simplified ANN. Generally, besides its high accuracy, one of the key
benefits of the presented ANN model is its applicability to a broader range of columns
than Eurocode 4 and other studies.",
publisher = "Springer",
journal = "Journal of Big Data",
title = "Practical ANN prediction models for the axial capacity of square CFST columns",
volume = "10",
doi = "10.1186/s40537-023-00739-y"
}

Đorđević, F.,& Kostić, S. M.. (2023). Practical ANN prediction models for the axial capacity of square CFST columns. in Journal of Big Data
Springer., 10.
https://doi.org/10.1186/s40537-023-00739-y

Đorđević F, Kostić SM. Practical ANN prediction models for the axial capacity of square CFST columns. in Journal of Big Data. 2023;10.
doi:10.1186/s40537-023-00739-y .

Đorđević, Filip, Kostić, Svetlana M., "Practical ANN prediction models for the axial capacity of square CFST columns" in Journal of Big Data, 10 (2023),
https://doi.org/10.1186/s40537-023-00739-y . .

TY  - JOUR
AU  - Kostić, Svetlana
AU  - Filippou, Filip C.
PY  - 2023
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3010
AB  - The paper presents an adaptive section discretization scheme for the inelastic response analysis of structural members with cross sections that can be decomposed into rectangular and circular subdomains. Each subdomain can consist of a different material. As long as the largest strain in a subdomain does not exceed the specified trigger strain values, the subdomain contribution to the section response is determined by the numerically exact cubature rule for the subdomain. Once the largest strain reaches the trigger value for a subdomain, it is discretized with a fiber mesh and the numerical evaluation of its contribution to the section response is determined with the midpoint
integration rule. The fiber mesh with the midpoint integration rule remains in effect for the activated subdomain until the end of the response history. The paper applies the adaptive discretization scheme to the thin-walled sections common in metallic structures and investigates the effect of different trigger strain values on the accuracy and computational efficiency of the inelastic response analysis of wide-flange steel sections and multistory steel frames under static and dynamic excitations.
T2  - Journal of Structural Engineering
T1  - An Adaptive Section Discretization Scheme for the Nonlinear Dynamic Analysis of Steel Frames
VL  - 149
DO  - 10.1061/JSENDH.STENG-11779
ER  - 

@article{
author = "Kostić, Svetlana and Filippou, Filip C.",
year = "2023",
abstract = "The paper presents an adaptive section discretization scheme for the inelastic response analysis of structural members with cross sections that can be decomposed into rectangular and circular subdomains. Each subdomain can consist of a different material. As long as the largest strain in a subdomain does not exceed the specified trigger strain values, the subdomain contribution to the section response is determined by the numerically exact cubature rule for the subdomain. Once the largest strain reaches the trigger value for a subdomain, it is discretized with a fiber mesh and the numerical evaluation of its contribution to the section response is determined with the midpoint
integration rule. The fiber mesh with the midpoint integration rule remains in effect for the activated subdomain until the end of the response history. The paper applies the adaptive discretization scheme to the thin-walled sections common in metallic structures and investigates the effect of different trigger strain values on the accuracy and computational efficiency of the inelastic response analysis of wide-flange steel sections and multistory steel frames under static and dynamic excitations.",
journal = "Journal of Structural Engineering",
title = "An Adaptive Section Discretization Scheme for the Nonlinear Dynamic Analysis of Steel Frames",
volume = "149",
doi = "10.1061/JSENDH.STENG-11779"
}

Kostić, S.,& Filippou, F. C.. (2023). An Adaptive Section Discretization Scheme for the Nonlinear Dynamic Analysis of Steel Frames. in Journal of Structural Engineering, 149.
https://doi.org/10.1061/JSENDH.STENG-11779

Kostić S, Filippou FC. An Adaptive Section Discretization Scheme for the Nonlinear Dynamic Analysis of Steel Frames. in Journal of Structural Engineering. 2023;149.
doi:10.1061/JSENDH.STENG-11779 .

Kostić, Svetlana, Filippou, Filip C., "An Adaptive Section Discretization Scheme for the Nonlinear Dynamic Analysis of Steel Frames" in Journal of Structural Engineering, 149 (2023),
https://doi.org/10.1061/JSENDH.STENG-11779 . .

TY  - JOUR
AU  - Nikolić, Jelena
AU  - Kostić, Svetlana
AU  - Stošić, Saša
PY  - 2023
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3118
AB  - The paper presents three-dimensional numerical models of short concrete-filled
steel tubular circular columns that can successfully describe the column behaviour
under axial compression. Several of the most commonly used material models for
the steel part and a concrete portion of the column are evaluated in the models. In
addition, the paper presents a new proposal for the extension of the Eurocode 2
stress-strain relation to make it suitable for describing the complex behaviour of
concrete inside the steel tube. This model overcomes the current limitations of the
Eurocode 2 design guide, referring to the limitation for the concrete curve in
compression to 3.5‰ strain. The ultimate axial column strength obtained by the
proposed model is compared to the ultimate column capacity calculated by a
simplified method provided in Eurocode 4. All presented numerical models are
validated on a set of experiments from the literature and demonstrate good
agreement. The comments about the accuracy of each model are provided, along
with the identified limitations.
T2  - Building Materials and Structures
T1  - Numerical modelling of concrete-filled steel tubular short columns under axial compression
IS  - 66
DO  - 10.5937/GRMK2300004N
ER  - 

@article{
author = "Nikolić, Jelena and Kostić, Svetlana and Stošić, Saša",
year = "2023",
abstract = "The paper presents three-dimensional numerical models of short concrete-filled
steel tubular circular columns that can successfully describe the column behaviour
under axial compression. Several of the most commonly used material models for
the steel part and a concrete portion of the column are evaluated in the models. In
addition, the paper presents a new proposal for the extension of the Eurocode 2
stress-strain relation to make it suitable for describing the complex behaviour of
concrete inside the steel tube. This model overcomes the current limitations of the
Eurocode 2 design guide, referring to the limitation for the concrete curve in
compression to 3.5‰ strain. The ultimate axial column strength obtained by the
proposed model is compared to the ultimate column capacity calculated by a
simplified method provided in Eurocode 4. All presented numerical models are
validated on a set of experiments from the literature and demonstrate good
agreement. The comments about the accuracy of each model are provided, along
with the identified limitations.",
journal = "Building Materials and Structures",
title = "Numerical modelling of concrete-filled steel tubular short columns under axial compression",
number = "66",
doi = "10.5937/GRMK2300004N"
}

Nikolić, J., Kostić, S.,& Stošić, S.. (2023). Numerical modelling of concrete-filled steel tubular short columns under axial compression. in Building Materials and Structures(66).
https://doi.org/10.5937/GRMK2300004N

Nikolić J, Kostić S, Stošić S. Numerical modelling of concrete-filled steel tubular short columns under axial compression. in Building Materials and Structures. 2023;(66).
doi:10.5937/GRMK2300004N .

Nikolić, Jelena, Kostić, Svetlana, Stošić, Saša, "Numerical modelling of concrete-filled steel tubular short columns under axial compression" in Building Materials and Structures, no. 66 (2023),
https://doi.org/10.5937/GRMK2300004N . .

TY  - CONF
AU  - Nikolić, Jelena
AU  - Kostić, Svetlana M.
AU  - Stošić, Saša
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2767
AB  - The paper presents the numerical modelling of concrete-filled steel tube stub columns under axial compression. The nonlinear 3D finite element model for the analysis was developed using ABAQUS software. The modelling, boundary conditions, the constitutive models for steel and concrete and contact interaction between the steel tube and concrete surface are discussed in detail. Three numerical models are proposed and validated using collected experimental data results. Finally, the composite column axial capacity is compared with the Eurocode 4 calculations for composite columns.
C3  - International Congress Proceedings / Association of Structural Engineers of Serbia, 16. Congress
T1  - Numerical modelling of concrete-filled steel tube columns under axial compression
IS  - 246-255
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2767
ER  - 

@conference{
author = "Nikolić, Jelena and Kostić, Svetlana M. and Stošić, Saša",
year = "2022",
abstract = "The paper presents the numerical modelling of concrete-filled steel tube stub columns under axial compression. The nonlinear 3D finite element model for the analysis was developed using ABAQUS software. The modelling, boundary conditions, the constitutive models for steel and concrete and contact interaction between the steel tube and concrete surface are discussed in detail. Three numerical models are proposed and validated using collected experimental data results. Finally, the composite column axial capacity is compared with the Eurocode 4 calculations for composite columns.",
journal = "International Congress Proceedings / Association of Structural Engineers of Serbia, 16. Congress",
title = "Numerical modelling of concrete-filled steel tube columns under axial compression",
number = "246-255",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2767"
}

Nikolić, J., Kostić, S. M.,& Stošić, S.. (2022). Numerical modelling of concrete-filled steel tube columns under axial compression. in International Congress Proceedings / Association of Structural Engineers of Serbia, 16. Congress(246-255).
https://hdl.handle.net/21.15107/rcub_grafar_2767

Nikolić J, Kostić SM, Stošić S. Numerical modelling of concrete-filled steel tube columns under axial compression. in International Congress Proceedings / Association of Structural Engineers of Serbia, 16. Congress. 2022;(246-255).
https://hdl.handle.net/21.15107/rcub_grafar_2767 .

Nikolić, Jelena, Kostić, Svetlana M., Stošić, Saša, "Numerical modelling of concrete-filled steel tube columns under axial compression" in International Congress Proceedings / Association of Structural Engineers of Serbia, 16. Congress, no. 246-255 (2022),
https://hdl.handle.net/21.15107/rcub_grafar_2767 .

TY  - CONF
AU  - Đorđević, Filip
AU  - Kostić, Svetlana M.
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2764
AB  - This paper proposes the use of artificial neural network (ANN) algorithms to estimate the ultimate compressive strength of slender circular concrete-filled steel tubular (CCFST) columns. A dataset of 1051 samples was applied to generate an appropriate ANN prognostic model. Empirical equations were also developed from the best neural network, and their results were compared with those obtained by Eurocode 4 (EC4) design code. Analyses show that the proposed ANN model has a better agreement with experimental results than those created with provisions of the EC4 design code.
C3  - 16th Congress of Association of Structural Engineers of Serbia
T1  - Estimation of ultimate strength of slender ccfst columns using artificial neural networks
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2764
ER  - 

@conference{
author = "Đorđević, Filip and Kostić, Svetlana M.",
year = "2022",
abstract = "This paper proposes the use of artificial neural network (ANN) algorithms to estimate the ultimate compressive strength of slender circular concrete-filled steel tubular (CCFST) columns. A dataset of 1051 samples was applied to generate an appropriate ANN prognostic model. Empirical equations were also developed from the best neural network, and their results were compared with those obtained by Eurocode 4 (EC4) design code. Analyses show that the proposed ANN model has a better agreement with experimental results than those created with provisions of the EC4 design code.",
journal = "16th Congress of Association of Structural Engineers of Serbia",
title = "Estimation of ultimate strength of slender ccfst columns using artificial neural networks",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2764"
}

Đorđević, F.,& Kostić, S. M.. (2022). Estimation of ultimate strength of slender ccfst columns using artificial neural networks. in 16th Congress of Association of Structural Engineers of Serbia.
https://hdl.handle.net/21.15107/rcub_grafar_2764

Đorđević F, Kostić SM. Estimation of ultimate strength of slender ccfst columns using artificial neural networks. in 16th Congress of Association of Structural Engineers of Serbia. 2022;.
https://hdl.handle.net/21.15107/rcub_grafar_2764 .

Đorđević, Filip, Kostić, Svetlana M., "Estimation of ultimate strength of slender ccfst columns using artificial neural networks" in 16th Congress of Association of Structural Engineers of Serbia (2022),
https://hdl.handle.net/21.15107/rcub_grafar_2764 .

TY  - CONF
AU  - Đorđević, Filip
AU  - Kostić, Svetlana M.
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2683
AB  - Due to numerous advantages, concrete-filled steel tubular (CFST) columns have an increasingly important role in the civil engineering industry. Because of the expensive experimental testing of these members, it is beneficial to provide prognostic models. In this study, an artificial neural network (ANN) model for predicting the axial compressive strength of square CFST columns has been developed. A dataset of 1022 samples (685 stub columns and 337 slender columns) was collected from available literature in order to compare the accuracy of the fast predictive Levenberg-Marquardt algorithm (LM) and Eurocode 4 (EC4) design code. Analyses showed that the ANN model has better accuracy than EC4. Over a whole domain, the ANN model has higher coefficient of determination (R2), and lower root mean squared error (RMSE). The same conclusion is valid when two separate datasets are considered: one for stub columns and the other for slender columns. The benefit of the ANN model is its applicability in a broader range of column parameters. At the same time, EC4 puts several limitations on its use and gives satisfactory results only in limited circumstances. Empirical equations have also been proposed from the best ANN model, which is useful for engineering practice.
C3  - First Serbian International Conference on Applied Artificial Intelligence, Kragujevac, Serbia
T1  - Axial Strength Prediction of Square CFST Columns Based on The ANN Model
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2683
ER  - 

@conference{
author = "Đorđević, Filip and Kostić, Svetlana M.",
year = "2022",
abstract = "Due to numerous advantages, concrete-filled steel tubular (CFST) columns have an increasingly important role in the civil engineering industry. Because of the expensive experimental testing of these members, it is beneficial to provide prognostic models. In this study, an artificial neural network (ANN) model for predicting the axial compressive strength of square CFST columns has been developed. A dataset of 1022 samples (685 stub columns and 337 slender columns) was collected from available literature in order to compare the accuracy of the fast predictive Levenberg-Marquardt algorithm (LM) and Eurocode 4 (EC4) design code. Analyses showed that the ANN model has better accuracy than EC4. Over a whole domain, the ANN model has higher coefficient of determination (R2), and lower root mean squared error (RMSE). The same conclusion is valid when two separate datasets are considered: one for stub columns and the other for slender columns. The benefit of the ANN model is its applicability in a broader range of column parameters. At the same time, EC4 puts several limitations on its use and gives satisfactory results only in limited circumstances. Empirical equations have also been proposed from the best ANN model, which is useful for engineering practice.",
journal = "First Serbian International Conference on Applied Artificial Intelligence, Kragujevac, Serbia",
title = "Axial Strength Prediction of Square CFST Columns Based on The ANN Model",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2683"
}

Đorđević, F.,& Kostić, S. M.. (2022). Axial Strength Prediction of Square CFST Columns Based on The ANN Model. in First Serbian International Conference on Applied Artificial Intelligence, Kragujevac, Serbia.
https://hdl.handle.net/21.15107/rcub_grafar_2683

Đorđević F, Kostić SM. Axial Strength Prediction of Square CFST Columns Based on The ANN Model. in First Serbian International Conference on Applied Artificial Intelligence, Kragujevac, Serbia. 2022;.
https://hdl.handle.net/21.15107/rcub_grafar_2683 .

Đorđević, Filip, Kostić, Svetlana M., "Axial Strength Prediction of Square CFST Columns Based on The ANN Model" in First Serbian International Conference on Applied Artificial Intelligence, Kragujevac, Serbia (2022),
https://hdl.handle.net/21.15107/rcub_grafar_2683 .

TY  - CONF
AU  - Kostić, Svetlana
AU  - Filippou, Filip C.
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2824
AB  - The paper summarises a family of adaptive fiber section discretization schemesfor nonlinear frame elements. The proposed schemes use cubature integration rules forintegration within the linear-elastic part of a section and continuously increase the numberof section integration points with growing plastic deformations. Consequently, the algorithmimproves section integration using the optimal number of integration points, which results inconsiderably reduced analysis time and better computational efficiency. On the other side,the proposed discretizations keep the numerical accuracy of the regular fiber sectiondiscretization schemes. The algorithm is provided for full (homogeneous and composite)and thin-walled cross-sections. Depending on the type of analysis, the reduction in analysistime goes from 30% to 85% compared to the regular discretization. The savings achievedusing these adaptive section discretizations are especially valuable when several hundreds ofnonlinear time history analyses need to be performed.
C3  - Conference: Third European Conference on Earthquake Engineering and Seismology
T1  - Efficient Adaptive Section Discretization Schemes
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2824
ER  - 

@conference{
author = "Kostić, Svetlana and Filippou, Filip C.",
year = "2022",
abstract = "The paper summarises a family of adaptive fiber section discretization schemesfor nonlinear frame elements. The proposed schemes use cubature integration rules forintegration within the linear-elastic part of a section and continuously increase the numberof section integration points with growing plastic deformations. Consequently, the algorithmimproves section integration using the optimal number of integration points, which results inconsiderably reduced analysis time and better computational efficiency. On the other side,the proposed discretizations keep the numerical accuracy of the regular fiber sectiondiscretization schemes. The algorithm is provided for full (homogeneous and composite)and thin-walled cross-sections. Depending on the type of analysis, the reduction in analysistime goes from 30% to 85% compared to the regular discretization. The savings achievedusing these adaptive section discretizations are especially valuable when several hundreds ofnonlinear time history analyses need to be performed.",
journal = "Conference: Third European Conference on Earthquake Engineering and Seismology",
title = "Efficient Adaptive Section Discretization Schemes",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2824"
}

Kostić, S.,& Filippou, F. C.. (2022). Efficient Adaptive Section Discretization Schemes. in Conference: Third European Conference on Earthquake Engineering and Seismology.
https://hdl.handle.net/21.15107/rcub_grafar_2824

Kostić S, Filippou FC. Efficient Adaptive Section Discretization Schemes. in Conference: Third European Conference on Earthquake Engineering and Seismology. 2022;.
https://hdl.handle.net/21.15107/rcub_grafar_2824 .

Kostić, Svetlana, Filippou, Filip C., "Efficient Adaptive Section Discretization Schemes" in Conference: Third European Conference on Earthquake Engineering and Seismology (2022),
https://hdl.handle.net/21.15107/rcub_grafar_2824 .

TY  - JOUR
AU  - Kostić, Svetlana M.
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2766
AB  - The paper proposes an adaptive fiber section discretization scheme for inelastic frame elements. The scheme uses cubature rules for the efficient and accurate evaluation of the section response over the elastic portion of the section. As inelastic strains arise and penetrate
into the section from the edges, the scheme converts the area under inelastic strains to a regular fiber discretization. This approach offers considerable advantages for the computational efficiency of large structural models with inelastic frame elements by minimizing the number of integration points in sections with limited inelastic response. The proposed scheme is presented for circular and rectangular cross sections, but the approach is applicable to other section shapes. Inelastic frame response examples demonstrate the benefits of the proposed discretization scheme for the nonlinear response history analysis of large structural models.
PB  - American Society of Civil Engineers
T2  - Journal of Structural Engineering
T1  - An Adaptive Fiber Section Discretization Scheme for Nonlinear Frame Analysis
IS  - 12
VL  - 148
DO  - 10.1061/JSENDH.STENG-10688
ER  - 

@article{
author = "Kostić, Svetlana M.",
year = "2022",
abstract = "The paper proposes an adaptive fiber section discretization scheme for inelastic frame elements. The scheme uses cubature rules for the efficient and accurate evaluation of the section response over the elastic portion of the section. As inelastic strains arise and penetrate
into the section from the edges, the scheme converts the area under inelastic strains to a regular fiber discretization. This approach offers considerable advantages for the computational efficiency of large structural models with inelastic frame elements by minimizing the number of integration points in sections with limited inelastic response. The proposed scheme is presented for circular and rectangular cross sections, but the approach is applicable to other section shapes. Inelastic frame response examples demonstrate the benefits of the proposed discretization scheme for the nonlinear response history analysis of large structural models.",
publisher = "American Society of Civil Engineers",
journal = "Journal of Structural Engineering",
title = "An Adaptive Fiber Section Discretization Scheme for Nonlinear Frame Analysis",
number = "12",
volume = "148",
doi = "10.1061/JSENDH.STENG-10688"
}

Kostić, S. M.. (2022). An Adaptive Fiber Section Discretization Scheme for Nonlinear Frame Analysis. in Journal of Structural Engineering
American Society of Civil Engineers., 148(12).
https://doi.org/10.1061/JSENDH.STENG-10688

Kostić SM. An Adaptive Fiber Section Discretization Scheme for Nonlinear Frame Analysis. in Journal of Structural Engineering. 2022;148(12).
doi:10.1061/JSENDH.STENG-10688 .

Kostić, Svetlana M., "An Adaptive Fiber Section Discretization Scheme for Nonlinear Frame Analysis" in Journal of Structural Engineering, 148, no. 12 (2022),
https://doi.org/10.1061/JSENDH.STENG-10688 . .

TY  - CONF
AU  - Đorđević, Filip
AU  - Kostić, Svetlana M.
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2682
AB  - The composite concrete-filled steel tube columns are structural members with numerous advantages over the traditional reinforced concrete or the pure steel members. The behavior of these columns is highly nonlinear. This paper analyses the determination of the ultimate compressive capacity of circular concrete-filled tubes according to the Eurocode 4 design code and its accuracy in comparison with the experimentally available results from the literature. In order to improve the predictions of the column’s ultimate compressive capacity, two efficient machine learning algorithms are employed separately for the stub and the slender columns. The analyzed algorithms are the Decision tree and the Random forest. The research used an experimental dataset of 508 samples: 236 tests on the stub columns and 272 tests on the slender columns. It adapted the dataset to the provision of the Eurocode 4 design code. The predictions of the column’s ultimate axial capacity obtained by two ML algorithms and the Eurocode 4 are compared with the experimental test results on the validation dataset. The calculated R2 error measure has shown that the predictions obtained by the tree-based algorithms are superior compared to the design formulas offered by the Eurocode 4. The decision tree algorithm achieved the best accuracy measured with the highest value of R2 error measure between the two algorithms. The two analyzed algorithms are used to perform the sensitivity analysis on the considered problem. The sensitivity analysis used the feature importance, a technique that assigns a score to each of the input features based on their influence on the prediction of the output variable. As expected, the sensitivity analysis identified the outer diameter of the columns’ cross-section as the parameter with the most significant impact on the results.
C3  - 8th International Conference Science and Practice, Kolasin, Montenegro
T1  - Prediction of Ultimate Compressive Strength of CCFT Columns Using Machine Learning Algorithms
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2682
ER  - 

@conference{
author = "Đorđević, Filip and Kostić, Svetlana M.",
year = "2022",
abstract = "The composite concrete-filled steel tube columns are structural members with numerous advantages over the traditional reinforced concrete or the pure steel members. The behavior of these columns is highly nonlinear. This paper analyses the determination of the ultimate compressive capacity of circular concrete-filled tubes according to the Eurocode 4 design code and its accuracy in comparison with the experimentally available results from the literature. In order to improve the predictions of the column’s ultimate compressive capacity, two efficient machine learning algorithms are employed separately for the stub and the slender columns. The analyzed algorithms are the Decision tree and the Random forest. The research used an experimental dataset of 508 samples: 236 tests on the stub columns and 272 tests on the slender columns. It adapted the dataset to the provision of the Eurocode 4 design code. The predictions of the column’s ultimate axial capacity obtained by two ML algorithms and the Eurocode 4 are compared with the experimental test results on the validation dataset. The calculated R2 error measure has shown that the predictions obtained by the tree-based algorithms are superior compared to the design formulas offered by the Eurocode 4. The decision tree algorithm achieved the best accuracy measured with the highest value of R2 error measure between the two algorithms. The two analyzed algorithms are used to perform the sensitivity analysis on the considered problem. The sensitivity analysis used the feature importance, a technique that assigns a score to each of the input features based on their influence on the prediction of the output variable. As expected, the sensitivity analysis identified the outer diameter of the columns’ cross-section as the parameter with the most significant impact on the results.",
journal = "8th International Conference Science and Practice, Kolasin, Montenegro",
title = "Prediction of Ultimate Compressive Strength of CCFT Columns Using Machine Learning Algorithms",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2682"
}

Đorđević, F.,& Kostić, S. M.. (2022). Prediction of Ultimate Compressive Strength of CCFT Columns Using Machine Learning Algorithms. in 8th International Conference Science and Practice, Kolasin, Montenegro.
https://hdl.handle.net/21.15107/rcub_grafar_2682

Đorđević F, Kostić SM. Prediction of Ultimate Compressive Strength of CCFT Columns Using Machine Learning Algorithms. in 8th International Conference Science and Practice, Kolasin, Montenegro. 2022;.
https://hdl.handle.net/21.15107/rcub_grafar_2682 .

Đorđević, Filip, Kostić, Svetlana M., "Prediction of Ultimate Compressive Strength of CCFT Columns Using Machine Learning Algorithms" in 8th International Conference Science and Practice, Kolasin, Montenegro (2022),
https://hdl.handle.net/21.15107/rcub_grafar_2682 .

TY  - JOUR
AU  - Lazović Radovanović, Marija
AU  - Nikolić, Jelena
AU  - Radovanović, Janko
AU  - Kostić, Svetlana M.
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2655
AB  - The paper discusses the structural behaviour of concrete-filled steel tube columns (CFT)
when applied to the top-down construction method as temporary internal supports for ceilings. Their
ultimate capacity to take into account the actual boundary conditions of the column is essential for
successful application in construction. The paper presents the full-scale in situ testing of four slender
specimens with variable D/t ratios under concentric axial loading. The CFT columns were supported
on the previously jacked concrete piles. In addition, detailed finite element numerical models in
ABAQUS and PLAXIS computer programs were developed. The models include the nonlinear
behaviour of materials and the nonlinear behaviour of soil. The soil–pile–column interaction and
impact of the CFT column–pile connection stiffness on global column stability were considered.
The numerical model was validated by comparison with the experimental results. In conclusion,
the coefficient for the effective buckling length of the studied columns is proposed. Finally, the
experimental results of the critical buckling forces were compared with widely used international
design codes Eurocode 4-EC4, American standard-ACI and the Australian standard-AS.
T2  - Applied Sciences
T1  - Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method
VL  - 12(8), 3771
DO  - https://doi.org/10.3390/app12083771
ER  - 

@article{
author = "Lazović Radovanović, Marija and Nikolić, Jelena and Radovanović, Janko and Kostić, Svetlana M.",
year = "2022",
abstract = "The paper discusses the structural behaviour of concrete-filled steel tube columns (CFT)
when applied to the top-down construction method as temporary internal supports for ceilings. Their
ultimate capacity to take into account the actual boundary conditions of the column is essential for
successful application in construction. The paper presents the full-scale in situ testing of four slender
specimens with variable D/t ratios under concentric axial loading. The CFT columns were supported
on the previously jacked concrete piles. In addition, detailed finite element numerical models in
ABAQUS and PLAXIS computer programs were developed. The models include the nonlinear
behaviour of materials and the nonlinear behaviour of soil. The soil–pile–column interaction and
impact of the CFT column–pile connection stiffness on global column stability were considered.
The numerical model was validated by comparison with the experimental results. In conclusion,
the coefficient for the effective buckling length of the studied columns is proposed. Finally, the
experimental results of the critical buckling forces were compared with widely used international
design codes Eurocode 4-EC4, American standard-ACI and the Australian standard-AS.",
journal = "Applied Sciences",
title = "Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method",
volume = "12(8), 3771",
doi = "https://doi.org/10.3390/app12083771"
}

Lazović Radovanović, M., Nikolić, J., Radovanović, J.,& Kostić, S. M.. (2022). Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method. in Applied Sciences, 12(8), 3771.
https://doi.org/https://doi.org/10.3390/app12083771

Lazović Radovanović M, Nikolić J, Radovanović J, Kostić SM. Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method. in Applied Sciences. 2022;12(8), 3771.
doi:https://doi.org/10.3390/app12083771 .

Lazović Radovanović, Marija, Nikolić, Jelena, Radovanović, Janko, Kostić, Svetlana M., "Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method" in Applied Sciences, 12(8), 3771 (2022),
https://doi.org/https://doi.org/10.3390/app12083771 . .

TY  - CONF
AU  - Bendić, Milica
AU  - Kostić, Svetlana M.
AU  - Nikolić, Jelena
PY  - 2021
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2365
AB  - The paper presents the calculation of continuous composite steel-concrete
beams with a partial shear connection and ductile shear connectors. The algorithm for
determining the ultimate load as a function of shear resistance capacity is explained. The
calculation is applied to a numerical example. The obtained results are discussed.
Guidelines for further research in this area are given.
C3  - 8th INTERNATIONAL CONFERENCE Contemporary achievements in civil engineering, Subotica, Serbia
T1  - Continuous Composite Steel Concrete Beams with Partial Shear Connection
EP  - 171
SP  - 163
DO  - 10.14415/konferencijaGFS2021.14
ER  - 

@conference{
author = "Bendić, Milica and Kostić, Svetlana M. and Nikolić, Jelena",
year = "2021",
abstract = "The paper presents the calculation of continuous composite steel-concrete
beams with a partial shear connection and ductile shear connectors. The algorithm for
determining the ultimate load as a function of shear resistance capacity is explained. The
calculation is applied to a numerical example. The obtained results are discussed.
Guidelines for further research in this area are given.",
journal = "8th INTERNATIONAL CONFERENCE Contemporary achievements in civil engineering, Subotica, Serbia",
title = "Continuous Composite Steel Concrete Beams with Partial Shear Connection",
pages = "171-163",
doi = "10.14415/konferencijaGFS2021.14"
}

Bendić, M., Kostić, S. M.,& Nikolić, J.. (2021). Continuous Composite Steel Concrete Beams with Partial Shear Connection. in 8th INTERNATIONAL CONFERENCE Contemporary achievements in civil engineering, Subotica, Serbia, 163-171.
https://doi.org/10.14415/konferencijaGFS2021.14

Bendić M, Kostić SM, Nikolić J. Continuous Composite Steel Concrete Beams with Partial Shear Connection. in 8th INTERNATIONAL CONFERENCE Contemporary achievements in civil engineering, Subotica, Serbia. 2021;:163-171.
doi:10.14415/konferencijaGFS2021.14 .

Bendić, Milica, Kostić, Svetlana M., Nikolić, Jelena, "Continuous Composite Steel Concrete Beams with Partial Shear Connection" in 8th INTERNATIONAL CONFERENCE Contemporary achievements in civil engineering, Subotica, Serbia (2021):163-171,
https://doi.org/10.14415/konferencijaGFS2021.14 . .

TY  - CONF
AU  - Nikolić, Jelena
AU  - Kostić, Svetlana M.
AU  - Deretić-Stojanović, Biljana
PY  - 2021
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2364
AB  - The paper compares the following methods for analysis of composite steel-concrete beams: the
“exact” analysis method, simplified method, effective modulus method and the method proposed
by Eurocode 4 design code. The exact analysis method is based on the application of linear
integral operators. Simplified analysis is derived from the exact method and adopts the
assumption that generalized displacements change linearly with the concrete creep function.
Effective modulus method and the method proposed by the Eurocode 4 design code are algebraic
methods, widely used in practice. The results obtained using the mentioned four methods are
compared on one example.
PB  - Univerzitet u Beogradu Građevinski fakultet
PB  - Društvo građevinskih konstruktera Srbije
C3  - 16th Congress hosted by Association of Structural Engineers of Serbia
T1  - Composite Steel-Concrete Beam Analysis using Different Methods
EP  - 336
SP  - 330
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2364
ER  - 

@conference{
author = "Nikolić, Jelena and Kostić, Svetlana M. and Deretić-Stojanović, Biljana",
year = "2021",
abstract = "The paper compares the following methods for analysis of composite steel-concrete beams: the
“exact” analysis method, simplified method, effective modulus method and the method proposed
by Eurocode 4 design code. The exact analysis method is based on the application of linear
integral operators. Simplified analysis is derived from the exact method and adopts the
assumption that generalized displacements change linearly with the concrete creep function.
Effective modulus method and the method proposed by the Eurocode 4 design code are algebraic
methods, widely used in practice. The results obtained using the mentioned four methods are
compared on one example.",
publisher = "Univerzitet u Beogradu Građevinski fakultet, Društvo građevinskih konstruktera Srbije",
journal = "16th Congress hosted by Association of Structural Engineers of Serbia",
title = "Composite Steel-Concrete Beam Analysis using Different Methods",
pages = "336-330",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2364"
}

Nikolić, J., Kostić, S. M.,& Deretić-Stojanović, B.. (2021). Composite Steel-Concrete Beam Analysis using Different Methods. in 16th Congress hosted by Association of Structural Engineers of Serbia
Univerzitet u Beogradu Građevinski fakultet., 330-336.
https://hdl.handle.net/21.15107/rcub_grafar_2364

Nikolić J, Kostić SM, Deretić-Stojanović B. Composite Steel-Concrete Beam Analysis using Different Methods. in 16th Congress hosted by Association of Structural Engineers of Serbia. 2021;:330-336.
https://hdl.handle.net/21.15107/rcub_grafar_2364 .

Nikolić, Jelena, Kostić, Svetlana M., Deretić-Stojanović, Biljana, "Composite Steel-Concrete Beam Analysis using Different Methods" in 16th Congress hosted by Association of Structural Engineers of Serbia (2021):330-336,
https://hdl.handle.net/21.15107/rcub_grafar_2364 .

TY  - CONF
AU  - Kostić, Svetlana
AU  - Filippou, Filip C.
PY  - 2019
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3033
C3  - The 16th International Conference on Civil, Structural & Environmental Engineering Computing, Riva del Garda, Italy
T1  - Efficient discretization of circular cross-section in fiber beam/column element
UR  - https://hdl.handle.net/21.15107/rcub_grafar_3033
ER  - 

@conference{
author = "Kostić, Svetlana and Filippou, Filip C.",
year = "2019",
journal = "The 16th International Conference on Civil, Structural & Environmental Engineering Computing, Riva del Garda, Italy",
title = "Efficient discretization of circular cross-section in fiber beam/column element",
url = "https://hdl.handle.net/21.15107/rcub_grafar_3033"
}

Kostić, S.,& Filippou, F. C.. (2019). Efficient discretization of circular cross-section in fiber beam/column element. in The 16th International Conference on Civil, Structural & Environmental Engineering Computing, Riva del Garda, Italy.
https://hdl.handle.net/21.15107/rcub_grafar_3033

Kostić S, Filippou FC. Efficient discretization of circular cross-section in fiber beam/column element. in The 16th International Conference on Civil, Structural & Environmental Engineering Computing, Riva del Garda, Italy. 2019;.
https://hdl.handle.net/21.15107/rcub_grafar_3033 .

Kostić, Svetlana, Filippou, Filip C., "Efficient discretization of circular cross-section in fiber beam/column element" in The 16th International Conference on Civil, Structural & Environmental Engineering Computing, Riva del Garda, Italy (2019),
https://hdl.handle.net/21.15107/rcub_grafar_3033 .

TY  - CONF
AU  - Kostić, Svetlana M.
AU  - Deretic-Stojanovic, Biljana
PY  - 2019
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2128
AB  - The paper presents and compares four methods for visco-elastic analysis of steel-concrete composite beams. The method denoted as "exact" is based on the use of linear integro-differential operators and besides inevitable approximations of the rheological properties of constituent materials does not introduce other mathematical simplifications. The underlying assumption of the simplified method is that unknown deformations change linearly with the concrete creep function. In the paper, the results of the analysis of continuous composite beam obtained using the mentioned two methods are compared with results of widely used the Effective modulus method and its modified form proposed by Eurocode 4. Results have shown that the simplified method gives solutions closest to the “exact” analysis method.
PB  - Serbian Society of Mechanics
C3  - Proceedings / The 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, June 24-26, 2019
T1  - Comparison of different methods for viscoelastic analysis of composite beams
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2128
ER  - 

@conference{
author = "Kostić, Svetlana M. and Deretic-Stojanovic, Biljana",
year = "2019",
abstract = "The paper presents and compares four methods for visco-elastic analysis of steel-concrete composite beams. The method denoted as "exact" is based on the use of linear integro-differential operators and besides inevitable approximations of the rheological properties of constituent materials does not introduce other mathematical simplifications. The underlying assumption of the simplified method is that unknown deformations change linearly with the concrete creep function. In the paper, the results of the analysis of continuous composite beam obtained using the mentioned two methods are compared with results of widely used the Effective modulus method and its modified form proposed by Eurocode 4. Results have shown that the simplified method gives solutions closest to the “exact” analysis method.",
publisher = "Serbian Society of Mechanics",
journal = "Proceedings / The 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, June 24-26, 2019",
title = "Comparison of different methods for viscoelastic analysis of composite beams",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2128"
}

Kostić, S. M.,& Deretic-Stojanovic, B.. (2019). Comparison of different methods for viscoelastic analysis of composite beams. in Proceedings / The 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, June 24-26, 2019
Serbian Society of Mechanics..
https://hdl.handle.net/21.15107/rcub_grafar_2128

Kostić SM, Deretic-Stojanovic B. Comparison of different methods for viscoelastic analysis of composite beams. in Proceedings / The 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, June 24-26, 2019. 2019;.
https://hdl.handle.net/21.15107/rcub_grafar_2128 .

Kostić, Svetlana M., Deretic-Stojanovic, Biljana, "Comparison of different methods for viscoelastic analysis of composite beams" in Proceedings / The 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, June 24-26, 2019 (2019),
https://hdl.handle.net/21.15107/rcub_grafar_2128 .

TY  - CHAP
AU  - Kostić, Svetlana M.
AU  - Deretić-Stojanović, Biljana
PY  - 2019
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2127
AB  - The paper presents four different methods for viscoelastic analysis of steel-concrete composite structures: “exact” analysis method, simplified method, effective modulus method and method proposed by the European design code, Eurocode 4. The exact analysis method uses the mathematical theory of linear integral operators for presenting viscoelastic relations of the steel-concrete composite structures. The simplified analysis method is derived from the exact method. It adopts the assumption that generalized displacements change linearly with the concrete creep function. Due to this assumption, the problem equations transforms from nonhomogeneous integral equations to nonhomogeneous algebraic equations. The effective modulus method and the method proposed by the Eurocode 4 are algebraic methods where stress-strain relations for concrete are expressed through the effective modulus, which depend on time. On the numerical example of continuous steel-concrete beam, the results obtained using the mentioned approximate and the exact method are compared
PB  - Univerzitet u Beogradu–Građevinski fakultet
PB  - Univerzitet Crne Gore–Građevinski fakultet
PB  - Akademija inženjerskih nauka Srbije
T2  - Teorija građevinskih konstrukcija
T1  - Tačna i približne metode proračuna spregnutih greda od čelika i betona
T1  - EXACT AND APPROXIMATE METHODS OF ANALYSIS OF STEEL-CONCRETE COMPOSITE BEAMS
EP  - 120
SP  - 113
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2127
ER  - 

@inbook{
author = "Kostić, Svetlana M. and Deretić-Stojanović, Biljana",
year = "2019",
abstract = "The paper presents four different methods for viscoelastic analysis of steel-concrete composite structures: “exact” analysis method, simplified method, effective modulus method and method proposed by the European design code, Eurocode 4. The exact analysis method uses the mathematical theory of linear integral operators for presenting viscoelastic relations of the steel-concrete composite structures. The simplified analysis method is derived from the exact method. It adopts the assumption that generalized displacements change linearly with the concrete creep function. Due to this assumption, the problem equations transforms from nonhomogeneous integral equations to nonhomogeneous algebraic equations. The effective modulus method and the method proposed by the Eurocode 4 are algebraic methods where stress-strain relations for concrete are expressed through the effective modulus, which depend on time. On the numerical example of continuous steel-concrete beam, the results obtained using the mentioned approximate and the exact method are compared",
publisher = "Univerzitet u Beogradu–Građevinski fakultet, Univerzitet Crne Gore–Građevinski fakultet, Akademija inženjerskih nauka Srbije",
journal = "Teorija građevinskih konstrukcija",
booktitle = "Tačna i približne metode proračuna spregnutih greda od čelika i betona, EXACT AND APPROXIMATE METHODS OF ANALYSIS OF STEEL-CONCRETE COMPOSITE BEAMS",
pages = "120-113",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2127"
}

Kostić, S. M.,& Deretić-Stojanović, B.. (2019). Tačna i približne metode proračuna spregnutih greda od čelika i betona. in Teorija građevinskih konstrukcija
Univerzitet u Beogradu–Građevinski fakultet., 113-120.
https://hdl.handle.net/21.15107/rcub_grafar_2127

Kostić SM, Deretić-Stojanović B. Tačna i približne metode proračuna spregnutih greda od čelika i betona. in Teorija građevinskih konstrukcija. 2019;:113-120.
https://hdl.handle.net/21.15107/rcub_grafar_2127 .

Kostić, Svetlana M., Deretić-Stojanović, Biljana, "Tačna i približne metode proračuna spregnutih greda od čelika i betona" in Teorija građevinskih konstrukcija (2019):113-120,
https://hdl.handle.net/21.15107/rcub_grafar_2127 .

TY  - CONF
AU  - Blagojević, Nikola
AU  - Kostić, Svetlana
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3261
AB  - The use of concrete filled steel tubes (CFT columns) in seismically active regions is becoming more common and widespread due to numerous advantages they offer over steel and reinforced concrete columns, such as increased ductility, buckling delay and good cyclic performance. Since the behavior of CFT columns is highly nonlinear, a numerical model needs to consider different nonlinear effects. The model proposed in this paper adopts the nonlinear force based beam/column element that takes into account the nonlinear behavior of steel and concrete, confinement effects and geometrical nonlinearities. Through a parametric study, different material
models for steel and concrete, widely available in commercial software programs, are evaluated and the constitutive model parameters that best approximate the behavior of CFT columns under static loading conditions are determined. This numerical model is then validated through a comparison with a number of experimental tests from the literature. Different types of loading (cyclic static and dynamic), types of structures with different slenderness of tested specimens and B/t ratio are considered. In addition, limitations of the proposed fiber element model for modelling CFT columns are emphasized.
C3  - 16th European Conference on Earthquake Engineering-Thessaloniki, 18 - 21 June, 2018
T1  - Nonlinear Analysis of Square CFT Columns with Fiber Beam/Column Element
UR  - https://hdl.handle.net/21.15107/rcub_grafar_3261
ER  - 

@conference{
author = "Blagojević, Nikola and Kostić, Svetlana",
year = "2018",
abstract = "The use of concrete filled steel tubes (CFT columns) in seismically active regions is becoming more common and widespread due to numerous advantages they offer over steel and reinforced concrete columns, such as increased ductility, buckling delay and good cyclic performance. Since the behavior of CFT columns is highly nonlinear, a numerical model needs to consider different nonlinear effects. The model proposed in this paper adopts the nonlinear force based beam/column element that takes into account the nonlinear behavior of steel and concrete, confinement effects and geometrical nonlinearities. Through a parametric study, different material
models for steel and concrete, widely available in commercial software programs, are evaluated and the constitutive model parameters that best approximate the behavior of CFT columns under static loading conditions are determined. This numerical model is then validated through a comparison with a number of experimental tests from the literature. Different types of loading (cyclic static and dynamic), types of structures with different slenderness of tested specimens and B/t ratio are considered. In addition, limitations of the proposed fiber element model for modelling CFT columns are emphasized.",
journal = "16th European Conference on Earthquake Engineering-Thessaloniki, 18 - 21 June, 2018",
title = "Nonlinear Analysis of Square CFT Columns with Fiber Beam/Column Element",
url = "https://hdl.handle.net/21.15107/rcub_grafar_3261"
}

Blagojević, N.,& Kostić, S.. (2018). Nonlinear Analysis of Square CFT Columns with Fiber Beam/Column Element. in 16th European Conference on Earthquake Engineering-Thessaloniki, 18 - 21 June, 2018.
https://hdl.handle.net/21.15107/rcub_grafar_3261

Blagojević N, Kostić S. Nonlinear Analysis of Square CFT Columns with Fiber Beam/Column Element. in 16th European Conference on Earthquake Engineering-Thessaloniki, 18 - 21 June, 2018. 2018;.
https://hdl.handle.net/21.15107/rcub_grafar_3261 .

Blagojević, Nikola, Kostić, Svetlana, "Nonlinear Analysis of Square CFT Columns with Fiber Beam/Column Element" in 16th European Conference on Earthquake Engineering-Thessaloniki, 18 - 21 June, 2018 (2018),
https://hdl.handle.net/21.15107/rcub_grafar_3261 .

TY  - CONF
AU  - Kostić, Svetlana M.
AU  - Deretić-Stojanović, Biljana
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1598
AB  - In  this  paper,  the  methods  for  determination  of  the  bending  resistance  of  composite  beams  with  partial  shear  connection  and  nonductile  shear  connectors,  according  to  Eurocode  4,  are  studied.  The  Eurocode  4  predicts  the  use  of  two  calculation  methods:  the  method  based  on  the  nonlinear  theory  and  the  simplified  method  that  assume  linear  relation  between  elastic  and  plastic  bending  moment  resistance. The algorithm for the nonlinear section analysis is explained in detail. Using the own computer program for nonlinear section analysis, for one composite beam cross section, the differences in results obtained by these two proposed methods are discussed.
PB  - Faculty of Civil Engineeirng, Subotica
C3  - Conference proceedings 6th international conference Contemporary Achievements in Civil Engineering 2018
T1  - Bending resistance of composite beams with nonductile shear connectors
T1  - Nosivost na savijanje spregnutih greda sa neduktilnim moždanicima
EP  - 32
SP  - 25
VL  - 34
DO  - 10.14415/konferencijaGFS2018.001
ER  - 

@conference{
author = "Kostić, Svetlana M. and Deretić-Stojanović, Biljana",
year = "2018",
abstract = "In  this  paper,  the  methods  for  determination  of  the  bending  resistance  of  composite  beams  with  partial  shear  connection  and  nonductile  shear  connectors,  according  to  Eurocode  4,  are  studied.  The  Eurocode  4  predicts  the  use  of  two  calculation  methods:  the  method  based  on  the  nonlinear  theory  and  the  simplified  method  that  assume  linear  relation  between  elastic  and  plastic  bending  moment  resistance. The algorithm for the nonlinear section analysis is explained in detail. Using the own computer program for nonlinear section analysis, for one composite beam cross section, the differences in results obtained by these two proposed methods are discussed.",
publisher = "Faculty of Civil Engineeirng, Subotica",
journal = "Conference proceedings 6th international conference Contemporary Achievements in Civil Engineering 2018",
title = "Bending resistance of composite beams with nonductile shear connectors, Nosivost na savijanje spregnutih greda sa neduktilnim moždanicima",
pages = "32-25",
volume = "34",
doi = "10.14415/konferencijaGFS2018.001"
}

Kostić, S. M.,& Deretić-Stojanović, B.. (2018). Bending resistance of composite beams with nonductile shear connectors. in Conference proceedings 6th international conference Contemporary Achievements in Civil Engineering 2018
Faculty of Civil Engineeirng, Subotica., 34, 25-32.
https://doi.org/10.14415/konferencijaGFS2018.001

Kostić SM, Deretić-Stojanović B. Bending resistance of composite beams with nonductile shear connectors. in Conference proceedings 6th international conference Contemporary Achievements in Civil Engineering 2018. 2018;34:25-32.
doi:10.14415/konferencijaGFS2018.001 .

Kostić, Svetlana M., Deretić-Stojanović, Biljana, "Bending resistance of composite beams with nonductile shear connectors" in Conference proceedings 6th international conference Contemporary Achievements in Civil Engineering 2018, 34 (2018):25-32,
https://doi.org/10.14415/konferencijaGFS2018.001 . .

TY  - JOUR
AU  - Kostić, Svetlana M.
AU  - Deretić-Stojanović, Biljana
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/980
AB  - The paper presents the nonlinear section analysis for composite steel-concrete beams with different degrees of shear connection. The analysis is fiber based, i.c., integration over the cross section is performed numerically, and any uniaxial nonlinear material model can be assigned to the steel and concrete parts of the cross section or to the reinforcement bars. The analysis assumed full interaction between steel and concrete and therefore, is suitable for analysis of composite steel-concrete beam cross sections with nonductile shear connectors. Its accuracy is verified on few experimental results. The presented section analysis is used in the parameter study in order to evaluate different methods proposed by design codes for determining the bending moment resistance of composite cross sections with nonductile shear connectors and different degrees of shear connection. The following effects are considered: variation of concrete and steel material models, presence of slab reinforcement, and creep of concrete. Special attention is paid on two different constructional methods: propped and unpropped. The weaknesses of the simplified design method in determining bending moment resistance are identified and recommendations for practical design analysis are formulated.
PB  - Hindawi Limited
T2  - Advances in Civil Engineering
T1  - Bending Resistance of Composite Sections with Nonductile Shear Connectors and Partial Shear Connection
DO  - 10.1155/2018/5350315
ER  - 

@article{
author = "Kostić, Svetlana M. and Deretić-Stojanović, Biljana",
year = "2018",
abstract = "The paper presents the nonlinear section analysis for composite steel-concrete beams with different degrees of shear connection. The analysis is fiber based, i.c., integration over the cross section is performed numerically, and any uniaxial nonlinear material model can be assigned to the steel and concrete parts of the cross section or to the reinforcement bars. The analysis assumed full interaction between steel and concrete and therefore, is suitable for analysis of composite steel-concrete beam cross sections with nonductile shear connectors. Its accuracy is verified on few experimental results. The presented section analysis is used in the parameter study in order to evaluate different methods proposed by design codes for determining the bending moment resistance of composite cross sections with nonductile shear connectors and different degrees of shear connection. The following effects are considered: variation of concrete and steel material models, presence of slab reinforcement, and creep of concrete. Special attention is paid on two different constructional methods: propped and unpropped. The weaknesses of the simplified design method in determining bending moment resistance are identified and recommendations for practical design analysis are formulated.",
publisher = "Hindawi Limited",
journal = "Advances in Civil Engineering",
title = "Bending Resistance of Composite Sections with Nonductile Shear Connectors and Partial Shear Connection",
doi = "10.1155/2018/5350315"
}

Kostić, S. M.,& Deretić-Stojanović, B.. (2018). Bending Resistance of Composite Sections with Nonductile Shear Connectors and Partial Shear Connection. in Advances in Civil Engineering
Hindawi Limited..
https://doi.org/10.1155/2018/5350315

Kostić SM, Deretić-Stojanović B. Bending Resistance of Composite Sections with Nonductile Shear Connectors and Partial Shear Connection. in Advances in Civil Engineering. 2018;.
doi:10.1155/2018/5350315 .

Kostić, Svetlana M., Deretić-Stojanović, Biljana, "Bending Resistance of Composite Sections with Nonductile Shear Connectors and Partial Shear Connection" in Advances in Civil Engineering (2018),
https://doi.org/10.1155/2018/5350315 . .

TY  - CONF
AU  - Kostić, Svetlana M.
AU  - Deretić-Stojanović, Biljana
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1645
PB  - Društvo građevinskih konstruktera Srbije, Beograd
C3  - ASES International congress proceedings / Association of Structural Engineers of Serbia, 15th Congress, September 6-8th, 2018, Zlatibor
T1  - Two numerical models for nonlinear analysis of CFT columns
UR  - https://hdl.handle.net/21.15107/rcub_grafar_1645
ER  - 

@conference{
author = "Kostić, Svetlana M. and Deretić-Stojanović, Biljana",
year = "2018",
publisher = "Društvo građevinskih konstruktera Srbije, Beograd",
journal = "ASES International congress proceedings / Association of Structural Engineers of Serbia, 15th Congress, September 6-8th, 2018, Zlatibor",
title = "Two numerical models for nonlinear analysis of CFT columns",
url = "https://hdl.handle.net/21.15107/rcub_grafar_1645"
}

Kostić, S. M.,& Deretić-Stojanović, B.. (2018). Two numerical models for nonlinear analysis of CFT columns. in ASES International congress proceedings / Association of Structural Engineers of Serbia, 15th Congress, September 6-8th, 2018, Zlatibor
Društvo građevinskih konstruktera Srbije, Beograd..
https://hdl.handle.net/21.15107/rcub_grafar_1645

Kostić SM, Deretić-Stojanović B. Two numerical models for nonlinear analysis of CFT columns. in ASES International congress proceedings / Association of Structural Engineers of Serbia, 15th Congress, September 6-8th, 2018, Zlatibor. 2018;.
https://hdl.handle.net/21.15107/rcub_grafar_1645 .

Kostić, Svetlana M., Deretić-Stojanović, Biljana, "Two numerical models for nonlinear analysis of CFT columns" in ASES International congress proceedings / Association of Structural Engineers of Serbia, 15th Congress, September 6-8th, 2018, Zlatibor (2018),
https://hdl.handle.net/21.15107/rcub_grafar_1645 .

TY  - JOUR
AU  - Blagojević, Nikola
AU  - Kostić, Svetlana M.
AU  - Stošić, Saša
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/891
AB  - The paper presents nonlinear analysis of square CFT columns using distributed plasticity fiber elements. Behaviour of CFT columns is nonlinear and it is necessary to include different nonlinear effects into the numerical model in order to simulate their behaviour properly. Model proposed in this work considers: nonlinear behaviour of concrete and steel using nonlinear stress-strain models, confinement effect and geometrical nonlinearities. Tests exposed to static loading with different slenderness, different D/t ratio (where D is the total dimension of a cross section and t is the thickness of steel tube) and different loading conditions are analyzed. Stress-strain models that best approximate the behaviour of CFT columns are determined from a detailed parametric study. The proposed numerical model is validated by comparing numerical with experimental results available in the literature.
AB  - U radu je prikazana nelinearna analiza kvadratnih CFT stubova, pomoću fiber konačnog elemenata raspodeljene plastičnosti. CFT stubove karakteriše nelinearno ponašanje, što je potrebno imati u vidu u numeričkom modelu. Model predložen u ovom radu uzima u obzir sledeće nelinearne uticaje: nelinearno ponašanje betona i čelika primenom odgovarajućih konstitutivnih relacija, efekat utezanja betona i geometrijske nelinearnosti. Analizirani su uzorci izloženi delovanju statičkog opterećenja koji imaju različitu vitkost, odnos D/t (odnos ukupne dimenzije čeličnog profila [D] i debljine čeličnog profila [t]), kao i uzorci izloženi različitim tipovima naprezanja. Na osnovu parametarske analize, određeni su modeli materijala za čelik i beton, kao i njihovi parametri koji najbolje aproksimiraju ponašanje CFT stubova. Tačnost modela proverena je zatim i upoređivanjem sa eksperimentalnim podacima dostupnim u literaturi.
PB  - Društvo za ispitivanje i istraživanje materijala i konstrukcija Srbije, Beograd
T2  - Građevinski materijali i konstrukcije
T1  - Fiber finite element in nonlinear analysis of square CFT columns
T1  - Fiber konačni element u nelinearnoj analizi kvadratnih spregnutih CFT stubova
EP  - 46
IS  - 1
SP  - 31
VL  - 60
DO  - 10.5937/grmk1701031B
ER  - 

@article{
author = "Blagojević, Nikola and Kostić, Svetlana M. and Stošić, Saša",
year = "2017",
abstract = "The paper presents nonlinear analysis of square CFT columns using distributed plasticity fiber elements. Behaviour of CFT columns is nonlinear and it is necessary to include different nonlinear effects into the numerical model in order to simulate their behaviour properly. Model proposed in this work considers: nonlinear behaviour of concrete and steel using nonlinear stress-strain models, confinement effect and geometrical nonlinearities. Tests exposed to static loading with different slenderness, different D/t ratio (where D is the total dimension of a cross section and t is the thickness of steel tube) and different loading conditions are analyzed. Stress-strain models that best approximate the behaviour of CFT columns are determined from a detailed parametric study. The proposed numerical model is validated by comparing numerical with experimental results available in the literature., U radu je prikazana nelinearna analiza kvadratnih CFT stubova, pomoću fiber konačnog elemenata raspodeljene plastičnosti. CFT stubove karakteriše nelinearno ponašanje, što je potrebno imati u vidu u numeričkom modelu. Model predložen u ovom radu uzima u obzir sledeće nelinearne uticaje: nelinearno ponašanje betona i čelika primenom odgovarajućih konstitutivnih relacija, efekat utezanja betona i geometrijske nelinearnosti. Analizirani su uzorci izloženi delovanju statičkog opterećenja koji imaju različitu vitkost, odnos D/t (odnos ukupne dimenzije čeličnog profila [D] i debljine čeličnog profila [t]), kao i uzorci izloženi različitim tipovima naprezanja. Na osnovu parametarske analize, određeni su modeli materijala za čelik i beton, kao i njihovi parametri koji najbolje aproksimiraju ponašanje CFT stubova. Tačnost modela proverena je zatim i upoređivanjem sa eksperimentalnim podacima dostupnim u literaturi.",
publisher = "Društvo za ispitivanje i istraživanje materijala i konstrukcija Srbije, Beograd",
journal = "Građevinski materijali i konstrukcije",
title = "Fiber finite element in nonlinear analysis of square CFT columns, Fiber konačni element u nelinearnoj analizi kvadratnih spregnutih CFT stubova",
pages = "46-31",
number = "1",
volume = "60",
doi = "10.5937/grmk1701031B"
}

Blagojević, N., Kostić, S. M.,& Stošić, S.. (2017). Fiber finite element in nonlinear analysis of square CFT columns. in Građevinski materijali i konstrukcije
Društvo za ispitivanje i istraživanje materijala i konstrukcija Srbije, Beograd., 60(1), 31-46.
https://doi.org/10.5937/grmk1701031B

Blagojević N, Kostić SM, Stošić S. Fiber finite element in nonlinear analysis of square CFT columns. in Građevinski materijali i konstrukcije. 2017;60(1):31-46.
doi:10.5937/grmk1701031B .

Blagojević, Nikola, Kostić, Svetlana M., Stošić, Saša, "Fiber finite element in nonlinear analysis of square CFT columns" in Građevinski materijali i konstrukcije, 60, no. 1 (2017):31-46,
https://doi.org/10.5937/grmk1701031B . .

TY  - CONF
AU  - Kostić, Svetlana M.
AU  - Deretić-Stojanović, Biljana
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1530
PB  - Serbian Society of Mechanics ; Faculty of Mechanical Engineering, University of Belgrade,Belgrade, Belgrade
C3  - Proceedings / The 6th International Congress of Serbian Society of Mechanics, Tara, June 19-21, 2017
T1  - An efficient model for nonlinear analysis of circular CFT columns
UR  - https://hdl.handle.net/21.15107/rcub_grafar_1530
ER  - 

@conference{
author = "Kostić, Svetlana M. and Deretić-Stojanović, Biljana",
year = "2017",
publisher = "Serbian Society of Mechanics ; Faculty of Mechanical Engineering, University of Belgrade,Belgrade, Belgrade",
journal = "Proceedings / The 6th International Congress of Serbian Society of Mechanics, Tara, June 19-21, 2017",
title = "An efficient model for nonlinear analysis of circular CFT columns",
url = "https://hdl.handle.net/21.15107/rcub_grafar_1530"
}

Kostić, S. M.,& Deretić-Stojanović, B.. (2017). An efficient model for nonlinear analysis of circular CFT columns. in Proceedings / The 6th International Congress of Serbian Society of Mechanics, Tara, June 19-21, 2017
Serbian Society of Mechanics ; Faculty of Mechanical Engineering, University of Belgrade,Belgrade, Belgrade..
https://hdl.handle.net/21.15107/rcub_grafar_1530

Kostić SM, Deretić-Stojanović B. An efficient model for nonlinear analysis of circular CFT columns. in Proceedings / The 6th International Congress of Serbian Society of Mechanics, Tara, June 19-21, 2017. 2017;.
https://hdl.handle.net/21.15107/rcub_grafar_1530 .

Kostić, Svetlana M., Deretić-Stojanović, Biljana, "An efficient model for nonlinear analysis of circular CFT columns" in Proceedings / The 6th International Congress of Serbian Society of Mechanics, Tara, June 19-21, 2017 (2017),
https://hdl.handle.net/21.15107/rcub_grafar_1530 .

TY  - CONF
AU  - Blagojević, Nikola
AU  - Kostić, Svetlana M.
AU  - Blagojević, Predrag
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1514
C3  - 5th International Conference Contemporary Achievements in Civil Engineering
T1  - Comparative analysis of reinforced concrete and CFT columns in buildings
EP  - 130
SP  - 121
DO  - 10.14415/konferencijaGFS2017.012
ER  - 

@conference{
author = "Blagojević, Nikola and Kostić, Svetlana M. and Blagojević, Predrag",
year = "2017",
journal = "5th International Conference Contemporary Achievements in Civil Engineering",
title = "Comparative analysis of reinforced concrete and CFT columns in buildings",
pages = "130-121",
doi = "10.14415/konferencijaGFS2017.012"
}

Blagojević, N., Kostić, S. M.,& Blagojević, P.. (2017). Comparative analysis of reinforced concrete and CFT columns in buildings. in 5th International Conference Contemporary Achievements in Civil Engineering, 121-130.
https://doi.org/10.14415/konferencijaGFS2017.012

Blagojević N, Kostić SM, Blagojević P. Comparative analysis of reinforced concrete and CFT columns in buildings. in 5th International Conference Contemporary Achievements in Civil Engineering. 2017;:121-130.
doi:10.14415/konferencijaGFS2017.012 .

Blagojević, Nikola, Kostić, Svetlana M., Blagojević, Predrag, "Comparative analysis of reinforced concrete and CFT columns in buildings" in 5th International Conference Contemporary Achievements in Civil Engineering (2017):121-130,
https://doi.org/10.14415/konferencijaGFS2017.012 . .

TY  - JOUR
AU  - Deretić-Stojanović, Biljana
AU  - Kostić, Svetlana M.
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/878
AB  - The paper presents the simplified matrix stiffness method for analysis of composite and prestressed beams. The method is based on the previously developed "exact" analysis method that uses the mathematical theory of linear integral operators to derive all relations without any mathematical simplifications besides inevitable idealizations related to the material rheological properties. However, the method is limited since the closed-form solution can be found only for specific forms of the concrete creep function. In this paper, the authors proposed the simplified analysis method by introducing the assumption that the unknown deformations change linearly with the concrete creep function. Adopting this assumption, the nonhomogeneous integral system of equations of the "exact" method simplifies to the system of algebraic equations that can be easily solved. Therefore, the proposed method is more suitable for practical applications. Its high level of accuracy in comparison to the "exact" method is preserved, which is illustrated on the numerical example. Also, it is more accurate than the well-known EM method.
PB  - Techno Press
T2  - Steel and Composite Structures
T1  - A simplified matrix stiffness method for analysis of composite and prestressed beams
EP  - 63
IS  - 1
SP  - 53
VL  - 24
DO  - 10.12989/scs.2017.24.1.053
ER  - 

@article{
author = "Deretić-Stojanović, Biljana and Kostić, Svetlana M.",
year = "2017",
abstract = "The paper presents the simplified matrix stiffness method for analysis of composite and prestressed beams. The method is based on the previously developed "exact" analysis method that uses the mathematical theory of linear integral operators to derive all relations without any mathematical simplifications besides inevitable idealizations related to the material rheological properties. However, the method is limited since the closed-form solution can be found only for specific forms of the concrete creep function. In this paper, the authors proposed the simplified analysis method by introducing the assumption that the unknown deformations change linearly with the concrete creep function. Adopting this assumption, the nonhomogeneous integral system of equations of the "exact" method simplifies to the system of algebraic equations that can be easily solved. Therefore, the proposed method is more suitable for practical applications. Its high level of accuracy in comparison to the "exact" method is preserved, which is illustrated on the numerical example. Also, it is more accurate than the well-known EM method.",
publisher = "Techno Press",
journal = "Steel and Composite Structures",
title = "A simplified matrix stiffness method for analysis of composite and prestressed beams",
pages = "63-53",
number = "1",
volume = "24",
doi = "10.12989/scs.2017.24.1.053"
}

Deretić-Stojanović, B.,& Kostić, S. M.. (2017). A simplified matrix stiffness method for analysis of composite and prestressed beams. in Steel and Composite Structures
Techno Press., 24(1), 53-63.
https://doi.org/10.12989/scs.2017.24.1.053

Deretić-Stojanović B, Kostić SM. A simplified matrix stiffness method for analysis of composite and prestressed beams. in Steel and Composite Structures. 2017;24(1):53-63.
doi:10.12989/scs.2017.24.1.053 .

Deretić-Stojanović, Biljana, Kostić, Svetlana M., "A simplified matrix stiffness method for analysis of composite and prestressed beams" in Steel and Composite Structures, 24, no. 1 (2017):53-63,
https://doi.org/10.12989/scs.2017.24.1.053 . .