Browsing by Author "Foroughi, Saeid"

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Analysis of Bending Moment-Curvature and the Damage Limits of Reinforced Concrete Circular Columns
(2020) Yüksel, S. Bahadır; Foroughi, Saeid
In this study; the effect of axial load levels, longitudinal reinforcement ratio, transverse reinforcement diameter and transverse reinforcement spacing were investigated on the moment curvature relationships of reinforced concrete columns. For this purpose, circular reinforced concrete columns having different parameters were designed considering the regulations of the Turkish Building Earthquake Code (2018). The behavior of the columns were investigated from the moment-curvature relation, by considering the nonlinear behavior of the materials taken into account. The moment-curvature relationships of the reinforced concrete column crosssections having different axial load levels have been obtained by considering Mander model, which considers the lateral, confined concrete strength. Moment-curvature relationships were obtained by SAP2000 Software, which takes the nonlinear behavior of materials into consideration. The designed reinforced concrete cross section models are considered to be composed of three components; cover concrete, confined concrete and reinforcement steel. The examined behavioral effects of the parameters were evaluated by the curvature and moment carrying capacity of the cross-sections. From the obtained moment-curvature relationship, cracking and destruction in cover and core concrete, yield and hardening conditions in reinforcement steel were calculated and the results were presented in charts and graphs. The confining effect in the core concrete is taken into account in the calculations. The behavior of the circular column sections and the types of refraction were interpreted according to the results obtained from the moment-curvature relationship of the sections. It is observed that the variation of the axial load, longitudinal reinforcement ratio, transverse reinforcement diameter and transverse reinforcement spacing have an important effect on the moment-curvature behavior of the reinforced concrete columns. The load bearing capacity of reinforced concrete column sections ends by destruction of the core concrete. Reinforced concrete column sections damaged by reinforcement yield before crushing of cover concrete exhibit more ductile behavior.
Analytical Investigation of Curvature Ductility of Reinforced Concrete Columns
(2020) Foroughi, Saeid; Yüksel, S. Bahadır
In this study; the effect of axial load, longitudinal reinforcement diameter, transverse reinforcement diameter and transverse reinforcement spacing were investigated on the moment curvature relationships of reinforced concrete columns. Reinforced concrete columns having different geometries were designed considering the regulations of Turkish Building Earthquake Codes (2018). Investigations of the effect of axial load, longitudinal reinforcement diameter, transverse reinforcement diameter and transverse reinforcement spacing on the behavior of the concrete columns are the main purpose of this study. The behavior of the columns was investigated from the moment-curvature relation, by considering the nonlinear behavior of the materials taken into account. The moment-curvature relationships of the reinforced concrete column cross-sections having different axial load levels have been obtained by considering Mander model which considers the lateral confined concrete strength. The examined effects of the parameters on the column behavior were evaluated in terms of curvature ductility and the moment capacity of the cross-section. In the designed column cross-sections, different parameters effecting the moment-curvature relationships were calculated and compared. It is observed that the variation of the axial load, longitudinal reinforcement diameter, transverse reinforcement diameter and transverse reinforcement spacing have an important effect on the moment-curvature behavior of the reinforced concrete columns.
Analytical Study of Strain Behaviour for Reinforced Concrete Coupling Beams
(2019) Foroughi, Saeid; Yüksel, Süleyman Bahadır
Bağ Kirişli Boşluklu Perde Duvarların Bağ Kirişlerinde Çapraz Donatıların Kesme Kapasitesinin Analitik Olarak Araştırılması
(2019) Yüksel, Süleyman Bahadır; Foroughi, Saeid
Bağ Kirişli Boşluklu Perde Duvarların Sismik Davranışlarının Araştırılması
(2019) Foroughi, Saeid; Yüksel, Süleyman Bahadır
Betonarme Dairesel Kolonların Kesme Dayanımı ile Deformasyon Kapasite Modellerinin Araştırılması
(2022) Yüksel, Süleyman Bahadır; Foroughi, Saeid
Göçme öncesi sismik performans seviyesinde, kesmeye maruz betonarme kolonların yatay yük ve eksenel yük taşıma kapasitelerindeki azalmayı ve bu davranışların tüm yapıya etkilerini modellemeye ve tahmin etmeye ihtiyaç vardır. Kesme dayanımı ile deformasyon kapasite davranışlarının incelenmesi için farklı beton basınç dayanımı, eksenel yük seviyesi ve spiral donatı oranlarında betonarme dairesel kolon modelleri tasarlanmıştır. Tasarlanan betonarme kolonların kesme davranışı ile deformasyon kapasiteleri, ASCE/SEI 41 (2017) ve araştırmacılar tarafından önerilen modellere göre araştırılmıştır. Betonarme kolonların moment-eğrilik ilişkilerinden elde edilen karakteristik değerlere göre elastik, plastik ve toplam yer değiştirme değerleri hesaplanarak yer değiştirme süneklik ilişkileri incelenmiştir. Betonarme kolonlar için analizlerden elde edilen kesme dayanımlarının eksenel yük seviyesi, beton basınç dayanımı, spiral donatı oranı ve yer değiştirme süneklik değerlerinden etkilendiği görülmektedir.
BETONARME KİRİŞLERİN ŞEKİL DEĞİŞTİRME ESASLI HASAR SINIRLARININ ARAŞTIRILMASI
(2020) Yüksel, S. Bahadır; Foroughi, Saeid; Jamal, Rohullah
Yapısal elemanların deprem performansının belirlenmesi için bu çalışmada, Türkiye Bina Deprem Yönetmeliği 2018’de betonarme elemanlar için öngörülen şekil değiştirme esaslı hasar sınırları analitik olarak incelenmiştir. Farklı geometri ve parametrelerde betonarme kiriş modelleri tasarlanmıştır. Gerçek malzeme davranışları esas alınarak elde edilen momenti-eğrilik ilişkilerinden kiriş kesitlerinin elastik ötesi davranışları incelenmiştir. Betonarme kiriş modelleri için moment-eğrilik ilişkilerinden elde edilen veriler kullanılarak kiriş kesitlerinin kırılma durumları ve davranışları incelenmiştir. Türkiye Bina Deprem Yönetmeliği 2018’de verilen hasar sınır değerleri betonarme kiriş modelleri için hesaplanmıştır. Şekil değiştirme değerleri TBDY 2018’de tanımlanmış olan Göçmenin Önlenmesi, Kontrollü Hasar ve Sınırlı Hasar Performans seviyeleri için hesaplanmıştır. Betonarme kirişler için göz önüne alınan üç ayrı hasar sınırı ve bu hasar sınırlarına karşı gelen birim şekil değiştirme değerleri incelenmiştir. İlgili yer değiştirme taleplerine karşılık gelen kiriş hasarları gözlenmiş ve hasar sınırları değerlendirilmiştir. Betonarme kirişlerde farklı performans düzeyi için beton ve donatı çeliği birim şekil değiştirmeleri ve plastik dönmeleri hesaplanarak performans düzeyleri araştırılmıştır. Göçmenin Önlenmesi ve Kontrollü Hasar performans düzeyleri için plastik dönmelerin hasar sınırları; akma eğriliği, kopma eğriliği, plastik mafsal uzunluğu, kesme açıklığı ve boyuna donatı çapının fonksiyonudur.
Betonarme Kolonların Sargısız ve Sargılı Beton Dayanımının Analitik Olarak Araştırılması
(2019) Yüksel, S. Bahadır; Foroughi, Saeid
Betonarme kolonlar taşıyıcı sistemlerin moment aktaran kritik yapısal sistemleridir ve yeterli dayanımve süneklikte tasarlanmalıdır. Betonarme kolonların sargı donatısı özellikle depreme maruz kaldıklarıdurumlarda sargı etkisi ile kolonların dayanım ve sünekliğinin artırmasında önemli rol oynar. Betonarmekolonlarda sargı donatısı boyuna donatının yerel burkulmasını geciktirmek, kesme kuvvetine karşıkoymak, ani kesme kırılmasını önlemek ve sargı etkisi ile dayanım ve sünekliği artırmak için kullanılır.Sismik yüklere maruz kalan betonarme elemanların davranışı, esas olarak betonun nihai dayanımına vesünekliğine bağlıdır. Bu parametreleri araştırmak için değişik geometride betonarme kolon modelleritasarlanmıştır. Sargı donatı çapının ve sargı donatı aralığının betonarme kolon modellerinin davranışınaetkisi analitik olarak araştırılmıştır. Sargı donatıları ile sarılmış betonarme kolon modellerinin davranışınıaraştırmak için literatüre sunulmuş olan analitik modeller kullanılmıştır. Farklı parametrelerde tasarlanansargılı kolon modelleri için gerilme-birim şekil değiştirme eğrileri çizilmiş ve elde edilen sonuçlarkarşılaştırılarak yorumlanmıştır.
Betonarme Kolonların Şekil Değiştirme Esaslı Hasar Sınırlarının Araştırılması
(2019) Foroughi, Saeid; Yüksel, S. Bahadır
Yapısal elemanların deprem performansının belirlenmesi için Türkiye Bina Deprem Yönetmeliği (2018)’de betonarme elemanlar için öngörülen şekil değiştirme esaslı hasar sınırları analitik olarak incelenmiştir. Farklı geometri ve parametrelerde betonarme kolon modelleri tasarlanmıştır. Gerçek malzeme davranışları esas alınarak elde edilen momenti-eğrilik ilişkilerinden kolon kesitlerinin elastik ötesi davranışları incelenmiştir. Türkiye Bina Deprem Yönetmeliği (2018)’de verilen hasar sınırları betonarme kolon modelleri için hesaplanmıştır. Betonarme kolonlarda üç farklı hasar sınırına karşı gelen birim şekil değiştirme değerleri hesaplanmıştır. Şekil değiştirme değerleri Türkiye Bina Deprem Yönetmeliği (2018)’de tanımlanmış olan Göçmenin Önlenmesi, Kontrollü Hasar ve Sınırlı Hasar Performans seviyeleri için hesaplanmıştır. Yer değiştirme taleplerine karşılık gelen kolon hasarları elde edilmiş ve hasar sınırları değerlendirilmiştir. Farklı performans düzeyleri için kolonların plastik mafsal bölgeleri için akma dönme değerleri ve plastik dönme değerleri hesaplanmıştır. Plastik mafsal bölgeleri için akma dönme değerleri eksenel yük seviyesi, boyuna donatı ve sargı donatı çapının artması ile artmaktadır. Göçmenin Önlenmesi ve Kontrollü Hasar performans düzeyleri için plastik dönmelerin hasar sınırları; akma eğriliği, kopma eğriliği, plastik mafsal uzunluğu, kesme açıklığı ve boyuna donatı çapının fonksiyonudur. Eksenel yük seviyesi, sargı donatısı ve boyuna donatı oranı gibi, akma eğriliği ve göçme öncesi eğrilik değerlerini etkileyen parametreler plastik dönme değerlerinde etkilemektedir.
Betonarme Perde Duvarların Doğrusal Olmayan Davranışlarının Araştırılması
(2019) Foroughi, Saeid; Yüksel, Süleyman Bahadır
Betonarme Perde Duvarların Hasar Sınırlarının Analitik Olarak Araştırılması
(2019) Yüksel, Süleyman Bahadır; Foroughi, Saeid
Betonarme Perde Duvarların Plastik Mafsal Uzunluklarının Araştırılması
(2019) Foroughi, Saeid; Yüksel, Süleyman Bahadır
Citation - Scopus: 3
Effect of Confining Reinforcement and Axial Load Level on Curvature Ductility and Effective Stiffness of Reinforced Concrete Columns
(TUBITAK, 2020) Foroughi, Saeid; Jamal, Rohullah; Yüksel, S. Bahadır
The correct estimate of curvature ductility of reinforced concrete members has always been an attractive subject of study as it engenders a reliable estimate of the capacity of buildings under seismic loads. In this study, the effect of the material model, axial load and transverse reinforcement ratio on the behavior of reinforced concrete columns were analytical investigated. Squared cross-section column models have been designed. The behaviors of the columns were evaluated from the moment-curvature relation by taking the nonlinear behavior of the materials into account. The moment-curvature relationships for different axial load levels and transverse reinforcement ratios of the reinforced concrete column cross-sections were obtained considering the Mander confined model. The examined effects of the parameters on the column behavior were evaluated in terms of the strength of the cross-section, ductility and effective stiffness. In the designed column cross-sections, different parameters effecting the moment-curvature relationships, ductility and effective stiffness were calculated and compared. It is observed that the variation of the axial load and transverse reinforcement ratio have an important effect on the moment-curvature behavior, ductility and effective stiffness of the reinforced concrete columns. Although the effective stiffness of the cracked section is not constant, it varies depends on parameters such as the confining reinforcement and axial force acting on the section. © 2020, TUBITAK. All rights reserved.
Effective Flexural Stiffness for Reinforced Concrete Shear Walls Having Confined Boundary Elements
(2021) Foroughi, Saeid; Yüksel, S. Bahadır
In the design of reinforced concrete (RC) shear walls strength, ductility and effective stiffness of the elements must be taken into account and are important parameters in terms of structural safety. Accurate estimation of the ductility and effective stiffnesses of RC members has always been an attractive subject of study as it provides a reliable estimate of the capacity of buildings under seismic loads. In this study, RC shear wall models with different concrete strength, longitudinal and transverse reinforcement ratios were designed to investigate effective section stiffness and coefficients. The effective stiffness of the cracked section in the RC shear walls designed in different parameters were analytically obtained. Analytically investigated parameters were calculated from TBEC (2018), ACI318 (2014), ASCE/SEI41 (2017) and Eurocode8 (2004, 2005) regulations and nonlinear behaviors. The results obtained according to different design parameters were compared and examined. In the relations suggested for the effective section stiffness coefficient, the confining effect is not taken into account as in the regulations. Therefore, it means neglecting the effects of parameters such as concrete strength, confining effect and axial load levels acting on the section. This situation can lead to unrealistic results in the design and evaluation of RC elements. For this reason, determining the moment-curvature relationship in the design and evaluation of RC elements and obtaining effective section stiffness values are of great importance in order to obtain more realistic results.
Investigation of Deformation-Based Damage Limits for RC Columns in Different Seismic Codes
(Academic Publication Council, 2023) Foroughi, Saeid; Yuksel, Suleyman Bahadir
The seismic performance of reinforced concrete (RC) columns is related to the expected damage limits under seismic loads and how this damage relates to the safety of the structure. To assess the performance of RC columns under seismic loads, performance-based deformation and damage limits have been proposed by seismic codes. Adequacy of the deformation and damage limits provided in the American Society of Civil Engineers, Seismic Evaluation and Retrofit of Existing Buildings Standard (ASCE/SEI-41, 2017) and the Turkish Building Earthquake Code (TBEC, 2018) were evaluated by performing parametric studies for RC columns. RC circular columns are designed in parametric studies to elucidate the effects of the compressive strength of concrete, axial load levels, and spiral reinforcement ratio on performance-based damage limits. The performance limits corresponding to each performance level obtained using different seismic guidelines were compared. The crosssection damage limits of ASCE/SEI-41 (2017) and TBEC (2018) were significantly different, which could change the performance level of the building. TBEC (2018) yielded approximately 50% conservative limits compared to the ASCE/SEI-41 (2017) limits. As a result, TBDY (2018) seems to offer safer and more ductile solutions than ASCE/SEI-41 (2017).
Investigation of Displacement Behavior of Reinforced Concrete Shear Walls With Different Plastic Hinge Relationships
(2019) Foroughi, Saeid; Yüksel, Süleyman Bahadır
The aim of this study is to investigate the plastic hinge length and peak displacement relationship for rectangular crosssectional high ductile concrete shear walls in seismic zones. For plastic hinge lengths related to seismic design; the conditions given in the current regulations are used in the literature. An analytical study was conducted to evaluate the peak displacement relationship of reinforced concrete shear walls in seismic loads under plastic hinge regions. The length of the plastic deformation zone called the plastic hinge length has been investigated in this study by considering the regulations proposed by different regulations and researchers. Plastic hinge lengths of the designed reinforced concrete shear walls were calculated by plastic hinge models proposed by different researchers and regulations. Then, according to the plastic hinge lengths obtained from different relations, the yield displacement and plastic displacement values of the reinforced concrete shear walls were calculated and the total peak displacement values of the shear walls were obtained. The results of this study indicated that increase in plastic hinge length has a significant effect on the displacement and displacement ductility values of reinforced concrete shear walls. The most important parameter affecting the plastic hinge length is the dimensions of the reinforced concrete shear walls.
Investigation of Moment-Curvature and Effective Section Stiffness of Reinforced Concrete Columns
(2021) Foroughi, Saeid; Yüksel, S. Bahadır
In determining the seismic performance of reinforced concrete (RC) structures in na?tional and international seismic code, it is desired to use effective section stiffness of the cracked section in RC structural elements during the design phase. Although the effective stiffness of the cracked section is not constant, it depends on parameters such as the dimension of the cross-section, concrete strength and axial force acting on the section. In this study, RC column models with different axial load levels, con?crete strength, longitudinal and transverse reinforcement ratios were designed to in?vestigate effective stiffness. Analytically investigated parameters were calculated from TBEC (2018), ACI318 (2014), ASCE/SEI41 (2017), Eurocode 2 (2004) and Eu?rocode8 (2004, 2005) regulations and moment-curvature relationships. From the numerical analysis results, it is obtained that the axial load level, concrete strength, longitudinal and transverse reinforcement ratios have an influence on the effective stiffness factor of RC column sections. The calculated effective stiffness for RC col?umns increases with increasing transverse reinforcement ratio, longitudinal rein?forcement ratio and concrete strength. Due to the increase of axial force, effective stiffness values of concrete have increased.
Investigation of Nonlinear Behavior of High Ductility Reinforced Concrete Shear Walls
(2020) Foroughi, Saeid; Yüksel, S. Bahadır
In this study, the nonlinear behavior of ductile reinforced concrete (RC) shear walls having different parameters was analytically investigated. The purpose of this study is to determine the effect of axial load, longitudinal reinforcement ratio and transverse reinforcement ratios on the moment-curvature and lateral force-lateral peak displacement relationships of RC shear walls. RC shear walls that have various parameters were designed by taking into account the regulation of the Turkish Building Earthquake Code (TBEC, 2018). By considering the nonlinear behavior of the materials, behaviors of the RC shear walls were examined within the framework of the moment-curvature relation. The moment-curvature relations of RC shear walls with different parameters were obtained with the Mander model which takes into consideration the lateral confined concrete strength for different parameters. The effects of the analyzed parameters on the nonlinear behavior of the RC shear walls were evaluated in terms of curvature ductility, moment capacity, peak displacement, the angular displacement and displacement ductility values. It was seen that changes in the transverse reinforcement, longitudinal reinforcement, and axial load levels had important influence on the moment-curvature and lateral force-lateral peak displacement behavior of the RC shear walls.
Citation - WoS: 1
Investigation of Nonlinear Behavior of the Reinforced Concrete Columns for Different Confined Concrete Models
(Gazi Univ, 2022) Foroughi, Saeid; Yüksel, S. Bahadır
Stress-strain and moment-curvature behavior of the reinforced concrete (RC) square columns have been analytically investigated according to different confined concrete models. The effect of transverse reinforcement diameter, transverse reinforcement spacing and concrete grade on the behavior of RC column models were investigated. For different confined concrete models, the confinement effectiveness coefficient, effective lateral confining stress, confined concrete compressive strength, strain at maximum concrete stress and ultimate concrete compressive strain values were calculated. In the second part, a parametric investigation was carried out for examining the effects of different design parameters on the moment-curvature relationships. Analytical moment-curvature relationships were obtained for RC cross-sections by using the TBEC (2018), Mander model (1988), Saatcioglu and Ravzi (1992) confined concrete models. The effects of the design parameters on the RC square column behavior were evaluated in terms of moment capacity and the curvature of the cross-section. In RC column models, stress-strain and moment-curvature relationships are obtained and compared according to different parameters. Confined concrete strength and the ultimate moment values obtained from the Mander model were higher than the Saatcioglu and Ravzi model when the transverse reinforcement close to the minimum spacing values. The results obtained from the Mander model and TBEC (2018) are close to each other.
Investigation of Nonlinear Displacement and Deformation Damage Limits of Reinforced Concrete Square Columns According To Ascesei 41-17
(2022) Yüksel, S. Bahadır; Foroughi, Saeid
The seismic performance of reinforced concrete columns is related to the expected damage limits under seismic loads and how this damage relates to safety of the structure. Accordingly, the estimation of reinforced concrete columns deformations become more critical than the estimation of internal forces since the deformations in the post elastic regions of the structure are well correlated with damage in these regions. In order to assess the performance of reinforced concrete columns under seismic loads, performance-based displacement and damage limits are proposed by certain codes. Adequacy of the displacement and damage limit levels given in the code such as ASCE/SEI-41 (2017) were evaluated by carrying out parametric studies for reinforced concrete columns. Reinforced concrete square columns are designed in parametric studies to present the effects of various parameters such as concrete compressive strength, axial load levels and transverse reinforcement ratio on performance-based damage limits. Performance limits corresponding to each performance levels obtained by ASCE/SEI-41 (2017) seismic code were compared. It is concluded that as the axial load levels increases, the damage limits become smaller, the amount of transverse reinforcement becomes more important at these load levels and the limitation stipulated by the regulation is highly effective.