Papers by Ertuğrul Türker Uzun
Pamukkale University Journal of Engineering Sciences, 2019
Due to technical developments and wider range of applications in the steel structures, significan... more Due to technical developments and wider range of applications in the steel structures, significance of the research on structural stability problems become forward. Lateral torsional buckling is a major problem especially for doubly symmetric I-shaped steel members subjected to flexure about their strong axis. If these members are not appropriately braced against lateral deflection and twisting, they are under the risk of failure by lateral torsional buckling prior to the reach their load carrying capacity. In this study, elastic lateral torsional buckling behavior of doubly symmetric I-shaped steel members under linear moment gradient is investigated considering a proposed method, several design standards and codes, approaches from the literature and finite element analysis. Proposed method herein is based on finite difference solution of lateral torsional buckling differential equation considering linear moment gradient. Different unbraced member lengths and various end moment values are considered in order to compare and evaluate these approaches in terms of critical moment and moment modification factor. Analysis results show that lateral torsional buckling is a key issue for doubly symmetric I-shaped steel members that are under flexure and it is reflected satisfactorily with the proposed method considering the design codes and standards, approaches from the literature and finite element analysis results.
Reliability of Corroded Steel Members Subjected to Elastic Lateral Torsional Buckling
International Journal of Steel Structures, Jul 19, 2021
Structural steel members are subjected to corrosion due to environmental condition. As a result, ... more Structural steel members are subjected to corrosion due to environmental condition. As a result, there is decreasing in the cross-section properties of the member. This causes different stability problems and reduction in the load carrying capacity of members. Then, the probability of failure, Pf increases due to corrosion. The need arises to determine expected level of safety for such members and systems. Besides, reliability of the steel structure is also effected by the structural stability problems that result decreasing in the resistance. Lateral torsional buckling is one of the most encountered problems in steel members and affected by the critical moment which is a function of lateral and torsional stiffness. Critical moment depends on the material properties, boundary conditions, unbraced length, load pattern, and the member’s cross section. Under the corrosion, it is inevitable to observe changing in some of properties. In this study, a damage model to determine the reliability of a corroded I-shape steel member under linear moment gradient is developed considering corrosion exposure time. Uniform and varying thickness loss models are considered to show the corrosion effect. Influence of environmental condition on the load carrying capacity of the members is considered and their effects on member design is evaluated. As a result, it is concluded that load carrying capacity of steel members degrades and safety of them adversely effected. With presented formulas, it is ensured that the load carrying capacity and reliability indices of the steel members can be calculated practically under the examined situations
Retrofitting of Masonry Structures Considering the Architectural Perspective: A Case Study in Foca, Izmir
IOP Conference Series: Materials Science and Engineering, 2019
Masonry structures have been preferred for centuries in most of the countries across the world be... more Masonry structures have been preferred for centuries in most of the countries across the world because they are easy to build and economical due to the use of local materials in their construction. As a result of high usage volume, masonry structures that created the architectural section of history and culture constitute an important part of the current building stock despite the developing and diversified construction techniques nowadays. The protection of these structures, which are important both in terms of their cultural values and their transfer to future generations, is of great importance in the architectural point of view. For this purpose, a masonry structure from Foca is selected. The material properties and architectural plan of the structure are determined in accordance with the original one. The structure is modelled by using a software program under seismic effects. Displacement and stress values for each acceleration record are obtained. Besides, an evaluation is made in the direction of the analysis results and it is determined according to the seismic performance of the structure. After that, the structure is retrofitted according to the current design codes and without distorting the architectural perspective. This study aims to increase the structural strength of the case building by using conventional and modern techniques for the recovery of the structure.
Pamukkale University Journal of Engineering Sciences, 2019
Due to technical developments and wider range of applications in the steel structures, significan... more Due to technical developments and wider range of applications in the steel structures, significance of the research on structural stability problems become forward. Lateral torsional buckling is a major problem especially for doubly symmetric I-shaped steel members subjected to flexure about their strong axis. If these members are not appropriately braced against lateral deflection and twisting, they are under the risk of failure by lateral torsional buckling prior to the reach their load carrying capacity. In this study, elastic lateral torsional buckling behavior of doubly symmetric I-shaped steel members under linear moment gradient is investigated considering a proposed method, several design standards and codes, approaches from the literature and finite element analysis. Proposed method herein is based on finite difference solution of lateral torsional buckling differential equation considering linear moment gradient. Different unbraced member lengths and various end moment values are considered in order to compare and evaluate these approaches in terms of critical moment and moment modification factor. Analysis results show that lateral torsional buckling is a key issue for doubly symmetric I-shaped steel members that are under flexure and it is reflected satisfactorily with the proposed method considering the design codes and standards, approaches from the literature and finite element analysis results.
Evaluation of Building Retrofitting Alternatives from Sustainability Perspective
Procedia Engineering, 2017
Abstract Buildings primarily provide shelter and acceptable comfort for its intended occupiers an... more Abstract Buildings primarily provide shelter and acceptable comfort for its intended occupiers and they should also provide adequate protection in case of hazards. Unfortunately, in case of seismic events it is observed that in many cases earthquakes caused considerable damage to residential and commercial buildings, public facilities and infrastructures with substantial casualties due to inadequate engineering and faulty in construction practices. In this study, a reinforced concrete residential building that collapsed in 1999 Kocaeli Turkey Earthquake (MW 7.4) is focused and investigated using current seismic code. Afterwards, building is virtually retrofitted considering architectural plan and using common retrofitting methods for satisfying current seismic code requirements. These retrofit alternatives are then evaluated from structural, cost and environmental aspects and outcomes are discussed. Since structural components that are used in retrofitting the building consumes natural resources and responsible for energy consumption, sustainability criteria should be directly included in the retrofitting requirements. Consequently, structural engineers are able to use natural resources efficiently and reduce the environmental impacts in retrofitting.
Corrosion Damage Analysis of Steel Frames Considering Lateral Torsional Buckling
Procedia Engineering, 2017
Abstract There is an increasing recognition that the conventional design of steel buildings for c... more Abstract There is an increasing recognition that the conventional design of steel buildings for collapse prevention is not sufficient for the necessities of the modern society. Structural designs that account durability and sustainability issues have gained attention. Beside all the advantages of steel structures, there are some drawbacks which are mainly related to deterioration especially in terms of corrosion. Corrosion problem is associated to the huge economic, social and environmental losses for steel constructions which should be investigated from all perspectives. In this study, steel frame structures are investigated under deterioration due to corrosion and nonlinear analysis are performed considering lateral torsional buckling. Numerical examples are provided in order to determine and evaluate the structural behavior under corrosion. Considering both corrosion and lateral torsional buckling in structural analysis decrease the load carrying capacity significantly and reveal the importance of corrosion in terms of structural behavior. The results of this study provide information about the decrease of the structural performance due to deterioration and underlines that steel frames that are under corrosion risk may not able to be fulfill their desired performance levels before their service life have expired.
Periodica Polytechnica Civil Engineering, 2019
Contemporary structural design approaches necessitates ways to determine realistic behavior of st... more Contemporary structural design approaches necessitates ways to determine realistic behavior of structures. For this purpose, inelastic ultimate load analysis methods are used widely since strength and stability of whole structure can be represented. In this study, a numerical method is proposed for determining inelastic ultimate load capacity of steel frames considering lateral torsional buckling behavior under distributed loads. In the analyses, inelastic material behavior, second-order effects and residual stresses of the structural frame system and its members are taken into account. Additionally, lateral torsional buckling behavior is considered in the analysis using finite difference method and it is used for determining the structural load carrying capacity of steel frames. Consequently, the problem associated with flexural capacity decreases due to lateral torsional buckling is precisely considered in the load increment steps of inelastic ultimate load analysis. In order to v...
Contemporary structural design approaches necessitates ways to determine realistic behavior of st... more Contemporary structural design approaches necessitates ways to determine realistic behavior of structures. For this purpose, inelastic ultimate load analysis methods are used widely since strength and stability of whole structure can be represented. In this study, a numerical method is proposed for determining inelastic ultimate load capacity of steel frames considering lateral torsional buckling behavior under distributed loads. In the analyses, inelastic material behavior, second-order effects and residual stresses of the structural frame system and its members are taken into account. Additionally, lateral torsional buckling behavior is considered in the analysis using finite difference method and it is used for determining the structural load carrying capacity of steel frames. Consequently, the problem associated with flexural capacity decreases due to lateral torsional buckling is precisely considered in the load increment steps of inelastic ultimate load analysis. In order to validate the proposed method, numerical examples from the literature are calculated considering the proposed method, AISC 360-16 design specification equations and approaches from the literature. Results of the numerical examples show that lateral torsional buckling is a key issue in determining structural load carrying capacity. Thus, proposed analysis method is shown to be an efficient and consistent tool for inelastic ultimate load analysis.
Due to technical developments and wider range of applications in the steel structures, significa... more Due to technical developments and wider range of applications in the steel structures, significance of the research on structural stability problems become forward. Lateral torsional buckling is a major problem especially for doubly symmetric I-shaped steel members subjected to flexure about their strong axis. If these members are not appropriately braced against lateral deflection and twisting, they are under the risk of failure by lateral torsional buckling prior to the reach their load carrying capacity. In this study, elastic lateral torsional buckling behavior of doubly symmetric I-shaped steel members under linear moment gradient is investigated considering a proposed method, several design standards and codes, approaches from the literature and finite element analysis. Proposed method herein is based on finite difference solution of lateral torsional buckling differential equation considering linear moment gradient. Different unbraced member lengths and various end moment values are considered in order to compare and evaluate these approaches in terms of critical moment and moment modification factor. Analysis results show that lateral torsional buckling is a key issue for doubly symmetric I-shaped steel members that are under flexure and it is reflected satisfactorily with the proposed method considering the design codes and standards, approaches from the literature and finite element analysis results.
IOP Conference Series: Materials Science and Engineering, 2019
Masonry structures have been preferred for centuries in most of the countries across the world be... more Masonry structures have been preferred for centuries in most of the countries across the world because they are easy to build and economical due to the use of local materials in their construction. As a result of high usage volume, masonry structures that created the architectural section of history and culture constitute an important part of the current building stock despite the developing and diversified construction techniques nowadays. The protection of these structures, which are important both in terms of their cultural values and their transfer to future generations, is of great importance in the architectural point of view. For this purpose, a masonry structure from Foca is selected. The material properties and architectural plan of the structure are determined in accordance with the original one. The structure is modelled by using a software program under seismic effects. Displacement and stress values for each acceleration record are obtained. Besides, an evaluation is made in the direction of the analysis results and it is determined according to the seismic performance of the structure. After that, the structure is retrofitted according to the current design codes and without distorting the architectural perspective. This study aims to increase the structural strength of the case building by using conventional and modern techniques for the recovery of the structure.
Lateral torsional buckling is a limit state for I-shaped steel beams that may often be a controll... more Lateral torsional buckling is a limit state for I-shaped steel beams that may often be a controlling issue in structural steel design. When these members are not appropriately braced so as to prevent lateral deformations and torsion, they are subjected to risk of failure by lateral torsional buckling before reaching their ultimate capacity. This paper investigates elastic lateral torsional buckling of simply supported I-shaped steel beams under concentrated load and linear moment gradient using design standards and codes, approaches from the literature and finite element analysis. Several unbraced member lengths and end moment values are taken into account to compare and evaluate these approaches in terms of elastic critical moment and end moment ratios. Analysis results show that lateral torsional buckling is a crucial stability problem for I-shaped steel members that are under flexure and it is reflected with adequate safety in the design codes and standards considering finite element analysis outcomes.
Procedia Engineering
There is an increasing recognition that the conventional design of steel buildings for collapse p... more There is an increasing recognition that the conventional design of steel buildings for collapse prevention is not sufficient for the necessities of the modern society. Structural designs that account durability and sustainability issues have gained attention. Beside all the advantages of steel structures, there are some drawbacks which are mainly related to deterioration especially in terms of corrosion. Corrosion problem is associated to the huge economic, social and environmental losses for steel constructions which should be investigated from all perspectives. In this study, steel frame structures are investigated under deterioration due to corrosion and nonlinear analysis are performed considering lateral torsional buckling. Numerical examples are provided in order to determine and evaluate the structural behavior under corrosion. Considering both corrosion and lateral torsional buckling in structural analysis decrease the load carrying capacity significantly and reveal the importance of corrosion in terms of structural behavior. The results of this study provide information about the decrease of the structural performance due to deterioration and underlines that steel frames that are under corrosion risk may not able to be fulfill their desired performance levels before their service life have expired.
Procedia Engineering
Buildings primarily provide shelter and acceptable comfort for its intended occupiers and they sh... more Buildings primarily provide shelter and acceptable comfort for its intended occupiers and they should also provide adequate protection in case of hazards. Unfortunately, in case of seismic events it is observed that in many cases earthquakes caused considerable damage to residential and commercial buildings, public facilities and infrastructures with substantial casualties due to inadequate engineering and faulty in construction practices. In this study, a reinforced concrete residential building that collapsed in 1999 Kocaeli Turkey Earthquake (MW 7.4) is focused and investigated using current seismic code. Afterwards, building is virtually retrofitted considering architectural plan and using common retrofitting methods for satisfying current seismic code requirements. These retrofit alternatives are then evaluated from structural, cost and environmental aspects and outcomes are discussed. Since structural components that are used in retrofitting the building consumes natural resources and responsible for energy consumption, sustainability criteria should be directly included in the retrofitting requirements. Consequently, structural engineers are able to use natural resources efficiently and reduce the environmental impacts in retrofitting.
Contemporary design codes necessitate ways to determine realistic behavior of structures. Nonline... more Contemporary design codes necessitate ways to determine realistic behavior of structures. Nonlinear analysis is used extensively for design purpose since strength and stability of the whole structure can be represented. In nonlinear analysis, some assumptions for stability issues are made to ensure the unrestricted plastic redistribution of moments between the frame members. In this study, a methodology is presented for improving nonlinear analysis of steel frames accounting lateral torsional buckling. Analysis results revealed that considering lateral torsional buckling in nonlinear analysis has decreased load carrying capacity severely and underlined the importance of structural stability.
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Papers by Ertuğrul Türker Uzun