Yazar "Saribas, Ilyas" seçeneğine göre listele

Listeleniyor 1 - 13 / 13
  • [ X ]
    Öğe
    Hybrid Use of Externally Embedded FRP Reinforcement for Seismic Retrofitting of Substandard RC Columns
    (Asce-Amer Soc Civil Engineers, 2023) Seyhan, Engin C.; Goksu, Caglar; Saribas, Ilyas; Ilki, Alper
    This paper discussed the effectiveness of the hybrid use of fiber-reinforced polymer (FRP) reinforcement for the seismic retrofitting of substandard reinforced concrete (RC) columns. Four columns, except for the reference, were retrofitted with externally embedded FRP (EE-FRP) bars in a longitudinal and external FRP jacket in the transverse directions. The test parameter was the configuration of the FRP bars that were used for retrofitting along the longitudinal direction (e.g., single or hybrid use of different types of FRP bars, such as aramid (AFRP), glass (GFRP), or carbon fiber-reinforced polymers (CFRP). The test results indicated that a significant enhancement in the lateral load capacity (<= 198% in the unstrengthened column) could be achieved through the hybrid use of FRP bars under reversed cyclic lateral displacement and a constant axial load without a significant sacrifice in deformability. In addition, the test results yielded insights into the strain (e) capacities of longitudinal FRP bars in tension and their contribution to compression resistance under reversed cyclic lateral loading conditions. In addition, an analytical study was conducted to predict the cyclic flexural behavior in substandard RC columns that were retrofitted through the single or hybrid use of EE-FRP bars that considered the debonding behavior of longitudinal CFRP bars with a smooth surface.
  • [ X ]
    Öğe
    Post-fire Seismic Behavior of RC Columns Built with Sustainable Concrete
    (Taylor & Francis Ltd, 2022) Demir, Ugur; Unal, Goktug; Goksu, Caglar; Saribas, Ilyas; Ilki, Alper
    In this study, four full-scale reinforced concrete columns were built replacing 50% of natural coarse aggregates in concrete mix by recycled aggregates. Three of the columns were exposed to standard ISO-834 fire for 30, 60 or 90 minutes, while the reference specimen was not exposed. Sixty days after fire exposure, the columns were tested under constant axial load and reversed cyclic lateral displacements simulating earthquakes. Test results are evaluated in terms of lateral load capacity, ductility, stiffness and energy dissipation. In addition, an analytical study was conducted to predict the lateral load-displacement response of fire-damaged columns built with recycled aggregates.
  • [ X ]
    Öğe
    Seismic performance of full-scale RC columns containing high proportion recycled aggregate
    (Springer, 2019) Saribas, Ilyas; Goksu, Caglar; Binbir, Ergun; Ilki, Alper
    The potential for utilizing high proportion recycled aggregates sourced from low strength waste concrete in new concrete construction is investigated in this paper. A comprehensive experimental program, consisting of ten full-scale, flexure critical reinforced concrete columns, five of which were constructed of natural concrete aggregate and five of which contained approximately 50% recycled concrete aggregate replacing the mid-sized coarse natural aggregate, was conducted to determine the effects of different axial loads and different spacings of transverse reinforcement on the seismic characteristics of columns incorporating recycled concrete aggregates. Seismic characteristics were quantified by analysis of hysteretic response, energy dissipation capacities, damage progression, residual displacement, and strain distribution of the longitudinal reinforcement. The test results indicate that the reinforced concrete columns constructed of natural aggregate concrete and those constructed of recycled aggregate concrete exhibit similar seismic performance, despite the fact that the compressive strength of the recycled aggregate concrete was slightly lower than that of the natural aggregate concrete. A theoretical study was then conducted to predict the load-displacement response of the columns. The comparison of the experimental data with the results of these theoretical calculations indicated that conventional RC design theory applied to columns incorporating natural aggregate is also valid for columns incorporating recycled aggregate. Finally, the confinement effect of the transverse reinforcement in columns subjected to low axial load were also critically evaluated for columns built with recycled aggregate concrete.
  • [ X ]
    Öğe
    Seismic performance of full-scale RC columns containing high proportion recycled aggregate (vol 17, pg 6009, 2019)
    (Springer, 2019) Saribas, Ilyas; Goksu, Caglar; Binbir, Ergun; Ilki, Alper
    [Abstract Not Available]
  • [ X ]
    Öğe
    Seismic performance of recycled aggregate-filled cantilever reinforced concrete retaining walls
    (Sage Publications Ltd, 2019) Saribas, Ilyas; Ok, Bahadir
    This study investigates the effects of the use of two different types of recycled aggregates with known characteristics as backfill materials in newly built cantilever reinforced concrete retaining walls on the seismic performance of the walls. The physical properties of the recycled aggregates used as backfill materials were determined using aggregate tests. Subsequently, analytical studies for the reinforced concrete retaining walls containing recycled aggregates in the amounts of 25%, 50%, 75%, and 100% were performed under seismic and static loads and the results were compared with those obtained for the retaining walls containing 100% natural aggregate as the backfill material. The experimental and analytical studies showed that the internal friction angles and effective ground acceleration coefficients significantly affected the overturning moment and total active pressure values of the retaining walls. The results led to the conclusion that recycled aggregates can be partially or completely used as the backfill material in retaining walls. Moreover, the current conventional calculation methods for design and analysis were proven valid for the reinforced concrete retaining walls containing recycled aggregates as backfill materials.
  • [ X ]
    Öğe
    Shear-flexure interaction in RAC columns under simulated seismic actions
    (Elsevier Ltd, 2021) Saribas, Ilyas; Goksu, Caglar; Binbir, Ergun; Ilki, Alper
    Inelastic flexural deformations adversely affect shear resistance of columns, and may cause building damage/collapse during earthquakes. In this paper, shear-flexure interaction on seismic performance of reinforced concrete columns constructed with recycled aggregate concrete is experimentally investigated. For this aim, reinforced concrete columns with low shear-span-to-depth ratio (2.3) were designed and constructed so that they reach their flexural lateral load capacities in accordance with capacity design principles, and the effect of shear deformations can be observed only after yielding of longitudinal reinforcing bars due to cyclic degradation. The shear-flexure interaction is characterized based on the amount of transverse reinforcement, and formulated within the framework of conventional reinforced concrete design theory during the design of the columns. These columns are then tested under the combined effects of axial and reversed cyclic lateral loads to simulate seismic loading. The recycled concrete aggregate is sourced from waste of low strength concrete, and replaced with 50% of natural coarse aggregate for the concrete mix. Comparison with columns constructed of natural aggregate is also presented in the study. The test results showed that the reinforced concrete columns either made of natural aggregate concrete or recycled aggregate concrete exhibited similar seismic performances for different interactions of shear and flexure. As the ratio of transverse reinforcement is reduced the deformation capability was reduced due to more pronounced effect of shear deformations. In addition, the load–displacement relationships determined through theoretical analysis were found to be compatible with the experimental data. Furthermore, a discussion on the minimum transverse reinforcement provisions of EN 1998-1, ACI 318-19 and TBEC-18 is also presented in order to investigate whether it is possible to reduce the required ratio of minimum transverse reinforcement per technical documents for the columns located in low to moderate seismicity regions. © 2021 Elsevier Ltd
  • [ X ]
    Öğe
    Structural Optimization Behavior of Green Concrete Members
    (Springer Heidelberg, 2022) Saribas, Ilyas
    The recycling process of construction and demolition waste, which started with brick pieces and brick dust used in the production of binder thousands of years ago, gained momentum after the second world war. Nowadays, the recycling activities of waste materials are sustained much more effectively by developing technology, machinery, and equipment. The obtained material by recycling waste concrete is called recycled concrete aggregate. And it has been stated in many experimental, analytical studies in the literature and more than one international material code that the recycled concrete aggregate, which meets specific material criteria, is an alternative to natural aggregate. This current study is carried out to give a different perspective and contribute to the literature on a not researched topic. Therefore, within the scope of this recent study, the structural topology optimization of structural members was performed by the isoline topology design method. The concrete properties of these members are considered with the natural concrete and the recycled aggregate concrete with four different recycled concrete aggregate ratios (25%, 50%, 75%, 100%). Besides, the structural topology optimization was performed by considering multi-material and single-material properties under similar loading conditions. As a result of the optimization process, the quantified optimization shapes indicated that the structural optimization behavior of multi-material structural members exhibits different optimization behavior depending on the recycled concrete aggregate ratios. However, considering the single-material situation, it is observed that the structural optimization behavior of structural members is similar for all concrete types. Finally, comparing the optimization shapes of natural concrete members with the recycled aggregate concrete members indicated that the structural topology optimization process applied to structural members incorporating natural concrete is also valid for recycled aggregate concrete members. In addition, a brief life cycle assessment of waste concrete was also carried out in this comprehensive study to emphasize the importance of recycling activities.
  • [ X ]
    Öğe
    The Behavior of Continuous Foundations with Sustainable Concrete and Soil Under Monotonic Loads
    (TUBITAK, 2022) Saribas, Ilyas; Ok, Bahadir
    Due to the renovation of structures, natural disasters, and regional-global wars, construction and demolition waste material is generated. The remediation of these wastes by recycling and reusing activities is one of recent most common research topics. Recycled aggregates are obtained through the recycling activities of these waste materials. In the literature, detailed studies have been carried out to use recycled aggregate as a sustainable product in producing new concrete or as a filling material. Besides, the scope of these studies continues to expand. In this comprehensive study, the structural behavior of the soil-structure interaction problem under the monotonic load, which is assumed to be produced with sustainable materials, was investigated. Furthermore, the concrete properties of these foundation beams representing the superstructure were considered with conventional and sustainable concrete. The characteristics of the filling materials were regarded with five different sustainable materials. The deflection, rotation, bending moment, shear force, and spring forces are obtained based on the numerical simulation. The sustainable soil-structure interaction problem results were compared with the conventional counterparts. Based on the comparisons, it was observed that the deflection, rotation, bending moment, shear force, and spring forces that occur in the foundation beam are affected by sustainable material properties. © 2022, TUBITAK. All rights reserved.
  • [ X ]
    Öğe
    The effect of various boron compounds on the antimicrobial activity of hardened mortars
    (Elsevier Sci Ltd, 2022) Iyigundogdu, Zeynep; Saribas, Ilyas
    This study has examined the effect of boron compounds on the mechanical and antimicrobial properties of hardened mortars. The antimicrobial activity of six different boron minerals and compounds was tested against six microorganisms, including Gram-positive and Gram-negative bacteria, yeast, and fungus. Cement mortars containing 5% (w/w) boron mineral addition by weight of cement were exposed to flexural and compression tests on the 7th, 28th and 90th days. At the end of the 90th day, the hardened mortar specimen prepared with 5% dicalcium hexaborate pentahydrate (COL) or 5% borax pentahydrate (BPH) decreased the compressive strength 7.41 % and 31.5 %, and flexural strength 13.5 % and 32 %, respectively. Although, there are decrements in both compressive and flexural strength, values remain within the acceptable limits specified in the material code. The antimicrobial activity of these specimens was evaluated with surface antimicrobial activity tests. The hardened mortar specimen containing boron compounds showed antimicrobial activity against C. albicans and A. niger. It can be concluded that from these results, using 5 % COL and 5 % BPH as an additive or replacement to the mortar, is an alternative way to create antimicrobial surfaces within environments that have complained of mold problems and biodegradation, such as in reinforced concrete structures or in conventional buildings that need to be free of pathogenic microorganisms.
  • [ X ]
    Öğe
    The Mechanical Properties of Green CO2ncrete Containing High Proportion RCA
    (Mehmet Sinan Bilgili, 2022) Caputcu, Ayten; Akyol, Asaf; Sari, Hatice Busra; Saribas, Ilyas
    Due to the rapid increase in the world population, many people are migrating from rural areas to cities. People migrating from rural areas to urban centers make these places their homes and rapidly increase the population in these cities. Thus, providing housing, energy, transportation, and other essential services to this growing population in urban centers has become unsustainable. In addition, a large part of the population in earthquake-prone countries lives in regions under disaster risk. Considering the parameters mentioned above, the basic shelter needs of the population living in urban centers should be solved safely and economically. Solving this need safely and financially is possible by making the risky areas safer. Furthermore, regarding the insufficient disaster resistance of the building stock in urban centers where the population is densely lived, safe and economic transformation gains even more critical. The safe and economical way of transforming these areas under disaster risk is urban transformation. Therefore, it will be possible to make the existing building stock in high-risk areas resistant to disasters with the urban transformation method. This method aims to demolish the structures that are not resistant to disasters and build new ones. Thus, a lot of waste concrete will emerge in this process. While there is more than one method for eliminating waste concrete, the most effective method among these is recycling. Thanks to this method, recycled concrete aggregate may be obtained from waste concrete. Besides, concrete produced from recycled aggregates is called green concrete or sustainable concrete. It should also be highlighted that detailed experimental and numerical studies have been carried out in recent years to demonstrate the usability of green concrete instead of conventional concrete. In most of these studies, it has been stated that recycled concrete aggregate and green concrete may be used in the production of new structures if the material conditions of codes are met. In this study, an experimental study has been conducted to determine the mechanical properties of green co2ncrete containing a high proportion of recycled concrete aggregate. Based on the fresh and hardened concrete tests, the mechanical properties of green concrete are similar to those of conventional concrete.
  • [ X ]
    Öğe
    The Numerical Simulation of Disturbed Region Corbels Containing Sustainable Concrete
    (Springer Heidelberg, 2023) Saribas, Ilyas
    The concept of sustainable concrete is aimed at using alternative materials instead of natural resources in concrete production. In recent years, many experimental and numerical studies have been carried out to show that sustainable concrete is an alternative to conventional concrete. In this study, a detailed numerical simulation of reinforced concrete corbels produced with sustainable concrete has been conducted comprehensively. According to the author's best knowledge, the novelty of this study: (1) this is the first time that comprehensive numerical simulation results of sustainable concrete corbels are reported in detail, (2) investigation of the applicability of existing numerical models in sustainable concrete corbels, (3) contribution the realistic simulation of the structural behavior of sustainable concrete corbels. It should also be highlighted that the variables included in the study were the recycled concrete aggregate ratio, the shear span-to-effective depth ratio, the tapering ratio, the angle between strut and tie element, and the amount of reinforcement. Furthermore, the numerical simulation results obtained by the finite element and truss analogy methods were extensively compared with the experimental results. In addition, a structural optimization design was executed on a short corbel to check the suitability of the selected truss analogy model. Based on the study, the simulation results obtained from the finite element method agreed fairly well with the experimental results. Furthermore, the truss analogy method provided relatively accurate and conservative results compared with the experimental results depending on the span-to-depth ratio. Besides, some recommendations for designing sustainable concrete corbels were also discussed.
  • [ X ]
    Öğe
    The numerical simulation of soil-structure interaction containing sustainable materials
    (Ice Publishing, 2022) Saribas, Ilyas; Ok, Bahadir
    As a result of urban transformation activities, natural disasters, regional and global wars, billions of tonnes of waste concrete occur. Therefore, the remediation process of waste concrete is one of the critical research topics of recent years. The sustainability concept provides a primary bridge between the demand for natural concrete material and the remediation process of waste concrete. Recycled aggregate and recycled concrete aggregate, which may be named sustainable materials, are obtained by the recycling process of waste concrete. Many experimental and numerical studies have been conducted in recent years to show that this sustainable material is an alternative product to natural aggregate. In this study, a comprehensive numerical simulation of foundation beams resting on soils incorporating conventional and sustainable materials has been performed. The foundation beams considered include some with conventional concrete properties and some with sustainable concrete properties. Additionally, the material conditions of soils are assessed, using six different mixed recycled aggregates as filling material. Based on the numerical simulation, the deflection, rotation, bending moment, shear force and spring force capacities of conventional and sustainable foundation beams resting on soils exhibited slightly different behaviour depending on the recycled concrete aggregate and mixed recycled aggregate ratios. Finally, comparing the numerical simulation results of soil-structural interaction members incorporating conventional and sustainable materials indicated that the soil-structure interaction modeling process applied to conventional foundation beams resting on soils is also valid for sustainable members.
  • [ X ]
    Öğe
    The Performance of Structural Members Incorporating Reinforced Sustainable CO2ncrete
    (Mehmet Sinan Bilgili, 2022) Saribas, Ilyas
    Some environmental, economic, and social problems have arisen during the COVID-19 pandemic. These effects have forced people to use natural and artificial resources more effectively and efficiently. In addition, although the pandemic affects more than one sector, the construction sector is one of the sectors most affected by these conditions. The groups affected by the increasing costs in the construction sector had to search for solutions to reduce these costs. One of the ways to make the construction industry cost-effective is sustainable concrete. Sustainable concrete will facilitate the rapid depletion of natural resources and production costs. Sustainable concrete, whose importance has increased even more with the pandemic conditions, and the performance of products made from this concrete has been extensively researched for nearly twenty years. Within the scope of this study, experimental and numerical studies on sustainable concrete structural members and structures, which the author has been working on for about ten years, are summarized comprehensively. In the experimental study, the performances of reinforced concrete columns and slabs produced from sustainable concrete were extensively investigated. The seismic performances of sustainable reinforced concrete structures and the structural performances of corbels, deep beams, and continuous foundations have been extensively investigated in the numerical analysis scope. Based on the data obtained from these studies, it has been evaluated that sustainable concrete can be used to produce new structures and structural elements with conventional construction techniques.