Sürdürülebilir Kalkınma Amaçları
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- ArticleAçık Erişim2026Functional Lightweight Concrete Systems for Sustainable Load-Bearing Applications: Experimental Assessment of Perlite-Modified Reinforced Concrete Beams
Polat, Melih Sakir; Turan, Ahmet İhsan; Kucuk, Mesut; Kumbasaroglu, Atila; Yalciner, Hakan; Ayaz, Yasar
The increasing demand for sustainable structural materials in the construction industry has intensified the need to develop high-performance and environmentally efficient reinforced concrete systems. In this context, the incorporation of functional material-enhanced concrete systems, including raw lightweight aggregates such as perlite, offers a promising pathway for reducing environmental impact while maintaining adequate structural performance. This study experimentally investigates the flexural behavior of reinforced concrete (RC) beams incorporating raw perlite aggregates within a functional material-enhanced structural framework. A total of four RC beams with identical geometry and reinforcement details were produced, including perlite aggregate beams (P25 and P40) and conventional aggregate beams (C25 and C40), corresponding to compressive strength classes of 25 MPa and 40 MPa. All specimens were tested under monotonic flexural loading conditions. The structural response was evaluated in terms of load–displacement behavior, stiffness degradation, ductility, energy dissipation capacity, moment–curvature response, and failure modes. The results indicate that perlite aggregate beams exhibit reduced stiffness and energy dissipation capacity compared to conventional counterparts at comparable mixture-average compressive-strength levels. However, the high-strength perlite beam (P40) demonstrated comparable flexural capacity and ductility to the normal-strength conventional beam (C25), highlighting its potential for sustainable structural applications. Furthermore, a building-scale environmental assessment based on a representative three-story reinforced concrete structure demonstrates that the use of raw perlite aggregates significantly reduces energy consumption, CO2-equivalent emissions, and water usage. From a functional materials perspective, the findings provide a basis for the future development of multifunctional load-bearing concrete systems, where lightweight aggregate substrates can be combined with protective or performance-enhancing coating technologies to achieve improved durability, environmental resistance, and structural efficiency. This integration could further enhance durability and long-term structural performance in load-bearing applications.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Experimental evaluation of reinforced concrete columns produced with natural perlite aggregates under cyclic loading
Atlı, Sefa; Yalciner, Hakan; Kumbasaroglu, Atila; Ayaz, Yaşar; Turan, Ahmet İhsan; Bulut, H. Alperen; Naimi, Sepanta
A total of four reinforced concrete (RC) columns were tested to compare the structural capacities of RC columns produced by natural perlite aggregates and conventional concrete. The structural performance of the RC columns made from natural perlite aggregates was compared to conventional RC columns regarding the same concrete strength levels, sectional properties, and reinforcement layouts of conventional RC columns. The RC columns were tested under a combined constant axial load ratio of 30% with cyclic loading for two concrete strength levels, namely, 25 and 40 MPa. Load–displacement curves, energy absorption capacities, stiffness degradation, the moment-curvature relationship, the plastic hinge mechanism, and the ductility index were experimentally obtained at two different concrete types along with the measured stress–strain properties of the conventional and perlite concrete. The test results showed that the construction of the RC columns using only perlite may become possible in the future by providing an adequate concrete stress–strain capacity, which will be improved. Additionally, the use of natural perlite aggregates can contribute to sustainable construction practices by reducing the reliance on conventional aggregates.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026The effect of elevated temperature on the mechanical properties of concrete produced with raw perlite aggregate
Ozturk, Akif Berke; Turan, Ahmet İhsan; Kumbasaroglu, Atila; Yalciner, Hakan; Ayaz, Yaşar
Deterioration caused by elevated temperatures in the micro- and macrostructure of concrete can lead to significant reductions in its mechanical performance, making it crucial to assess the residual behavior of concrete elements after thermal exposure. This study experimentally investigates the effects of elevated temperatures (25 °C, 200 °C, 400 °C, and 600 °C) on cubic and prismatic specimens produced with two different aggregate types (raw perlite aggregate and conventional coarse aggregate) across four mixtures (C25, C40, P25, and P40). Destructive (compressive and flexural strength) and non-destructive (ultrasonic pulse velocity, scanning electron microscopy) tests were conducted before and after thermal loading. Increasing the temperature to 600 °C reduced the compressive strength of conventional mixtures by 34.91 % (C25) and 41.79 % (C40), whereas perlite-based concretes exhibited significantly lower reductions of 9.91 % (P25) and 12.80 % (P40). Mass loss remained negligible (<2 %) up to 200 °C, increased to 4–6 % for conventional mixtures and 6–11 % for perlite-based mixtures at 400 °C, and reached 25–40 % and nearly 47 %, respectively, at 600 °C. UPV results revealed a substantial degradation in internal integrity at high temperatures, with decreases of 49–60 % in conventional concretes and only 16–17 % in perlite-based mixtures at 600 °C. Although the flexural strength of P25 and P40 was initially lower at 25 °C, their post-heating performance became comparable to conventional mixtures, showing similar residual flexural behavior at elevated temperatures. SEM observations further confirmed that perlite-based concretes exhibited fewer microcracks and reduced matrix deterioration compared to conventional mixtures. Overall, the findings clearly demonstrate that raw perlite aggregate significantly enhances the thermal resistance, internal stability, and residual durability of concrete, making it a promising sustainable alternative for structures exposed to elevated temperature environments.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2026Seismic Performance and Nonlinear Flexural Behavior of Corroded Reinforced Concrete Columns: An Analytical and Parametric Study
Çelik, Alper; Turan, Ahmet İhsan; Yalciner, Hakan; Kumbasaroglu, Atila
This study presents an analytical investigation and a parametric evaluation of the structural behavior and seismic performance of highly corroded reinforced concrete (RC) columns, based on previously conducted experimental studies by the authors. In the analytical phase, moment–curvature relationships were obtained by considering the deterioration of the mechanical properties of both concrete and reinforcing steel due to corrosion in RC column specimens. By linking the sectional moment–curvature response with the element-level behavior observed in the experimental program, the plastic hinge lengths and rotational capacities of the corroded RC columns were determined. Subsequently, a parametric study was carried out using the analytical framework developed in the first phase on a set of 48 RC column models. In this investigation, axial load ratio, concrete compressive strength, corrosion level, section type, and concrete cover depth were considered as key parameters. The results of the combined experimental and analytical investigations demonstrate that the adopted section analysis approach successfully captures the nonlinear flexural behavior observed in the corroded specimens and provides a reliable basis for evaluating the structural performance and for supporting the assessment of seismic performance of deteriorated RC columns.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2025An experimental evaluation on structural performance level of corroded reinforced concrete frames
Turan, Ahmet İhsan; Ayaz, Yaşar; Yalciner, Hakan; Kumbasaroglu, Atila
A total of 5 full-scale Reinforced Concrete (RC) frames were tested to develop new models for predicting the structural behavior of corroded RC frames and to verify the accuracy of the models mostly developed for RC columns. Four corroded and one non-corroded RC frame were tested under cyclic loading. Corroded RC frames were tested under displacement-controlled cyclic loading at four corrosion levels and for a constant applied axial load ratio of 0.20, with the same concrete compression strength level and reinforcement bar layout. Actual corrosion ratios were obtained following the loading tests, breaking all RC columns and beams and extracting all reinforcement bars from concrete. The test results demonstrated that the corrosion level played an active role in the structural capacity of the RC frames. Initial corrosion crack widths had more significant effects on structural performance. Some models proposed for corroded RC columns can also be used for corroded RC frames in terms of yield and ultimate load capacities according to the corrosion levels of the columns and beam composing the RC frame. It was also concluded from the test results that the displacement-based ductility ratio for corroded RC frames could still be misleading if they were not computed according to energy-based or bilateral failure criteria. Structural properties such as initial/secant stiffness and energy absorption capacity calculated based on experimental measurements for RC frames had further disclosed corrosion effects.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Experimental Investigation of Metamaterial-Inspired Periodic Foundation Systems with Embedded Piezoelectric Layers for Seismic Vibration Attenuation †
Oz, Mehmet Furkan; Kumbasaroglu, Atila; Yalciner, Hakan; Korozlu, Nurettin; Babacan, Yunus; Çatır, Fulya Esra Cimilli; Sayarcan, Done
Seismic metamaterial-inspired periodic foundations have emerged as promising vibration-mitigation concepts capable of attenuating seismic wave propagation within specific frequency bands. This study presents an experimental investigation on the dynamic response of periodic foundation configurations, with and without embedded piezoelectric layers, to evaluate their vibration-attenuation characteristics. The experimental program employed a shake table driven by a 0.75 kW servo motor and included excitation step counts of 3000, 4000, and 5000. Accelerometers mounted on the specimen surfaces recorded vibration data at 80 ms intervals. Three foundation configurations were tested: (i) a conventional reinforced concrete block, (ii) a one-dimensional periodic foundation composed of alternating concrete and rubber layers, and (iii) a periodic foundation incorporating piezoelectric modules. Time-domain and frequency-domain analyses showed that the periodic foundations achieved notable reductions in both peak and RMS accelerations, especially near resonance frequencies. The configuration, including piezoelectric layers, exhibited similar attenuation performance while also generating measurable instantaneous voltage outputs under vibration. However, these voltage peaks—reaching a maximum of 1.64 V—represent only a laboratory-scale, proof-of-concept demonstration of electromechanical coupling rather than a practical or continuous form of energy harvesting, given the inherently sporadic nature of seismic excitation. Overall, the results confirm that the tested system is not a full metamaterial in the classical sense but rather a metamaterial-inspired periodic arrangement capable of inducing band-gap-based vibration attenuation. The inclusion of piezoelectric elements provides auxiliary sensing and micro-energy-generation capabilities, offering a preliminary foundation for future multifunctional seismic-protection concepts.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Prediction of seismic performance levels of corroded RC frames based on crack width
Turan, Ahmet İhsan; Kumbasaroglu, Atila; Yalciner, Hakan; Ayaz, Yaşar
In reinforced concrete (RC) structures, corrosion of the reinforcement due to environmental factors or concrete components poses significant risks to both structural integrity and safety. Reinforcement corrosion, can be visually detected through cracks in the concrete cover, and this situation offers a practical approach to associating corrosion-induced cracks with structural parameter degradations caused by the corrosion mechanism. In this study, a total of five RC frame specimens were fabricated, with one specimen not exposed to corrosion and four specimens exposed to different levels of corrosion through the accelerated corrosion method, all having the same cross-section and material properties. In the experiments conducted under a constant 20 % axial load and cyclic repeated load effects, the structural performance indicators of the RC frame specimens were examined. Within the scope of the study, two experimental models are proposed. The first model aims to estimate the loss in the cross-sectional area of the reinforcement bar based on crack width, while the second model was oriented towards estimating the energy consumption capacity of the specimen for a specific displacement ratio based on the loss in the cross-sectional area of the reinforcement. The results revealed that as the corrosion ratio increased, the crack widths of the specimens also increased, and after a 1.5 % drift ratio, there was a significant decrease in the energy consumption capacities of the corroded specimens.
RDL Kalıcı Kaydıİncele - CorrectionYalnız künye2024Corrigendum to “Torsional behavior of reinforced concrete beams with corroded reinforcement” [Structures 20 (2019) 476–488, (S2352012419300931), (10.1016/j.istruc.2019.05.013)]
Yalciner, Hakan; Kumbasaroglu, Atila; Turan, Ahmet İhsan
The journal regret to find that [Figure presented] Fig. 8b is not printed in the paper.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Assessment of reinforced concrete building damages following the Kahramanmaraş earthquakes in Malatya, Turkey (February 6, 2023)
Ihsan Turan, Ahmet; Celik, Alper; Kumbasaroglu, Atila; Yalciner, Hakan
Earthquakes of magnitude Mw = 7.7 and Mw = 7.6 hit the city of Kahramanmaraş (Turkey) on 6 February 2023. These earthquakes caused serious damage in 11 provinces in Turkey resulting in over 50,000 deaths and huge economic losses with the collapse of thousands of buildings. Two consecutive devastating earthquakes have severely damaged the reinforced concrete building stock located in Malatya. There are many reasons reinforced concrete structures suffer damage under the influence of seismic loads. These reasons can be listed as material and section properties that do not comply with earthquake codes, workmanship defects, ground parameters that are not considered and design errors, as seen in field investigations after earthquakes in Turkey in the past. In this research, a field study was conducted on reinforced concrete buildings damaged after the earthquakes in Malatya province. The causes of structural damages in reinforced concrete buildings between 6–26 years of age were assessed in terms of design and material defects. The structural damages were mainly caused due to insufficient stirrups in structural members, short column, strong beam–weak column, failures of infill walls, soft story type collapse, poor concrete quality, and reinforcement corrosion. In addition to the field investigation, the spectrum relationships created using raw acceleration data obtained from DEMP (Disaster and Emergency Management Presidency) stations in Malatya province were compared with the design response spectra.
RDL Kalıcı Kaydıİncele - CorrectionAçık Erişim2024Corrigendum to “Torsional behavior of reinforced concrete beams with corroded reinforcement” [Structures 20 (2019) 476–488, (S2352012419300931), (10.1016/j.istruc.2019.05.013)]
Yalciner, Hakan; Turan, Ahmet İhsan; Kumbasaroglu, Atila
The journal regret to find that Fig. 7c is not printed in the paper.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2022Experimental Study to Predict Bond-Slip Behavior of Corroded Reinforced Concrete Columns
Yalciner, Hakan; Kumbasaroglu, Atila
To perform accurate seismic analyses of corroded reinforced concrete (RC) buildings, it is necessary to predict the bond-slip relationships to modify the moment-curvature relationships. In this study, empirical models were developed to predict the bond strength of corroded RC columns. Twenty-five RC columns were tested under combined cyclic lateral displacement excursions for three concrete strength levels-specifically, 9, 27, and 37 MPa (1305, 3915, and 5365 psi, respectively)-at two axial load ratios of 0.20 and 0.40 and at four corrosion levels. An accelerated corrosion method was applied to corrode the reinforcing bars embedded in the RC columns. The actual corrosion levels were determined by breaking the concrete and extracting all the longitudinal and transverse reinforcing bars from the RC columns. Three empirical models were developed. The first model was used to predict the development length of the corroded reinforcing bars. The second and third models were used to predict the bond strength and slip in the reinforcing bars as a function of the corrosion levels. The results indicated that previous models that predict the bond strength of corroded RC members were limited because of the theoretically considered development length of the noncorroded reinforcing bars.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022An experimental study on seismic performance levels of highly corroded reinforced concrete columns
Celik, Alper; Yalciner, Hakan; Kumbasaroglu, Atila; Turan, Ahmet İhsan
In the literature, only one empirical model is available as a nondestructive method for the prediction of seismic performance levels of corroded reinforced concrete (RC) columns as a function of the initial corrosion crack width at lower corrosion levels. Because of the ruptured transverse reinforcement bars at higher corrosion levels, the structural behavior may turn brittle in terms of shear failure. Therefore, in this study, higher corrosion levels for a different concrete strength level from that empirical model were studied. To do this, four RC columns were subjected to accelerated corrosion, and the widths of initial corrosion cracks were measured. The corroded RC columns were then tested under combined constant axial load and cyclic lateral displacement excursions. After the cyclic loading test, the actual corrosion levels at each reinforcement bar were obtained by extracting the reinforcement bars from the concrete. Test results showed that the prediction of seismic performance levels of corroded RC columns based on initial corrosion crack widths were limited owing to the nonlinear increase in the crack width with the increase in the corrosion levels. New empirical models were developed to predict the remaining energy capacities and seismic performance levels of the corroded RC columns.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2021Cyclic loading test on highly corroded reinforced concrete columns
Celik, Alper; Yalciner, Hakan; Kumbasaroglu, Atila; Turan, Ahmet Ihsan; Belletti, B.; Coronelli, D.
An experimental study was performed on five reinforced concrete (RC) columns to investigate the structural behavior of highly corroded RC columns. Four of the RC columns were corroded using an accelerated corrosion method for different corrosion levels at longitudinal bars as 15.4, 20.2, 27.3 and 28.3%. RC columns were tested under cyclic load for a constant axial load ratio of 0.40. After the loading test, the actual corrosion levels were obtained by extracting the longitudinal bars and stirrups following the breaking of the RC columns. Load-displacement curves, ductility ratios and energy absorption capacities of tested RC columns were obtained. Test results revealed that the ductility ratios of corroded RC columns should be determined in accordance with energy-based or bilateral failure criteria due to the misleading of increased ductility ratios of corroded RC columns based on the displacement method.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Effect of polypropylene fibers on the development lengths of reinforcement bars of slabs
Kumbasaroglu, Atila; Yalciner, Kürşad; Yalciner, Hakan; Turan, Ahmet I.; Celik, Alper
Ductile behavior is one of the most important earthquake indicators that must be possessed by structures. Because of the limited tensile strength of concrete, alternative materials such as structural nanosynthetic fibers as three-dimensional reinforcement bars have gained increasing popularity over several decades. However, the contribution of fibers to the development length of reinforcement bars has not been investigated. Therefore, an experimental study was conducted to investigate the effects of polypropylene fibers on the development lengths of reinforcement bars. Thirty-three reinforced concrete (RC) slabs at three different volume fractions of fibers of 0.0, 1.0 and 1.5 % at different embedment lengths of reinforcement bars were investigated under four-point flexural strength tests. Load-displacement curves, energy absorption capacities, ductility ratios and bond-slip relationships were obtained for different embedment lengths of reinforcement bars with three different amounts of fibers in RC concrete slabs. The test results revealed that the predominant effects of fibers on structural behavior pertained to the energy absorption capacities at plastic deformation. It was found that resisting more strains by reinforcement bars with the help of added polypropylene fibers resulted in the regaining of ductile behavior due to the reduced embedment lengths of the reinforcement bars.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2020Experimental evaluation and modeling of corroded reinforced concrete columns
Yalciner, Hakan; Kumbasaroglu, Atila
A total of 30 full-scale reinforced concrete (RC) columns were tested to develop models for the prediction of the structural behavior of corroded RC columns. Of these, 25 RC columns were tested under cyclic loading for two different applied axial load ratios-namely, 0.20 and 0.40-at three concrete strength levels-namely, 9, 27, and 37 MPa (1305, 3915, and 5365 psi)-and at four corrosion levels. Five RC columns were loaded monotonically with an axial load ratio of 0.20 at four corrosion levels to calculate the damage index. The actual corrosion levels were obtained by breaking the concrete and extracting all the reinforcing bars. The test results demonstrated that the ductility ratios of the corroded RC columns, which were not determined in accordance with energy-based or bilateral failure criteria, could be misleading. The determined energy dissipation capacity and damage index of the columns further revealed the corrosion effects.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2019Paslanmaya Maruz Kalmış Tam Ölçekli Betonarme Kolonların Monotonik Yükleme Etkisi Altında Yapısal Davranışlarının İncelenmesi: Korozyon Çalışmaları İçin Öneriler
Yalciner, Hakan; Mermit, Mehmet Fırat; Kohistani, Rameen; Karimi, Aqludin; Kumbasaroglu, Atila
Korozyona maruz kalmış betonarme yapıların sismik performanslarının tahmin edilmesi korozyona uğramamışyapılara göre daha zordur. Gerçekleştirilen bu deneysel çalışma ile birlikte korozyona maruz kalmış betonarmeelemanları üzerine yapılacak olan çalışmalara ışık tutulması amaçlanmıştır. Beş adet tam ölçekli betonarmekolonu hızlandırılmış korozyon yöntemi kullanılarak farklı korozyon oranları için paslandırılmıştır.Paslandırılmış betonarme kolonları sabit eksenel yük altında monotonik yüklemeye tabi tutularak, akma ve nihaiyükleri, süneklik oranları ve enerji yutma kapasiteleri deneysel olarak elde edilmiştir. Betonarme kolonlarındakigerçek korozyon oranları yükleme deneylerinden sonra betonarme kolonlarının kırılarak ve gömülü olan tümbetonarme donatılarının çıkartılması ile elde edilmiştir. Yapılan deneysel çalışma sonucunda, monotonikyüklemenin tersinir-tekrarlanır yüklemeye göre zayıf yönleri göz önüne alınan deprem indeksleri açısındandeğerlendirilmiştir. Elde edilen deneysel sonuçlar doğrultusunda ileriki korozyon çalışmaları için önemliönerilerde bulunulmuştur. Gerçekleştirilen bu çalışma kapsamında, paslanmış betonarme kolonlarınınmonotonik yükleme etkisi altında süneklik oranları ve enerji yutma kapasiteleri artan korozyon oranına bağlıolarak azalmıştır. Monotonik yükleme etkisi altında pasın belirli oranlarına kadar sağlamış olduğu sargı etkisive buna bağlı olarak deprem indekslerindeki artışlar net bir şekilde görülememiştir. Tek doğrultuda göçmemodu kabulü ile yapılacak olan sismik değerlendirmelerde kullanılmak üzere paslanmış betonarme kolonlarınsüneklik ve enerji yutma kapasitelerinin tahmin edilebilmesi için iki ampirik model geliştirilmiştir.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2019Torsional behavior of reinforced concrete beams with corroded reinforcement
Yalciner, Hakan; Kumbasaroglu, Atila; Turan, Ahmet İhsan
An experimental study was conducted to investigate the pure torsional moment capacities of corroded reinforced concrete beams. An accelerated corrosion pool was used to corrode the reinforcement bars embedded in reinforced concrete beams. Seven reinforced concrete beams at corrosion levels between 0% and 17% were examined under pure torsion tests. The actual corrosion levels were obtained by breaking the concrete and extracting the reinforcement bars from the concrete after the torsion tests. An empirical model was developed to predict the pure torsional moment capacities of the reinforced concrete beams as a function of the corrosion level. The experimental results showed that, compared to the cracking torque, the maximum torques and dissipated energy capacities of the corroded reinforced concrete beams were significantly reduced as the corrosion level increased. Nonuniform shear flow originating from the nonuniform formations due to corrosion through the depth of the diaphragm produced different cracking patterns. The failure modes of the corroded reinforced concrete beams were more severe if the diagonal compression struts were joined with bond cracking.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2019Prediction of seismic performance levels of corroded reinforced concrete columns as a function of crack width
Yalciner, Hakan; Kumbasaroglu, Atila; Karimi, Aqludin
An experimental study was conducted for the prediction of the seismic performance levels of corroded reinforced concrete (RC) columns as a function of the initial corrosion crack widths. A full-scale accelerated-corrosion pool was used to corrode 25 full-scale RC columns. The initial crack widths at different levels of corrosion were measured for three different concrete strength levels: 9, 27, and 37 MPa. The seismic performance levels of corroded RC columns under combined cyclic lateral-displacement excursions at two different axial-load ratios (0.20 and 0.40) were measured. The corrosion levels obtained for the initially measured corrosion crack widths were used for establishing a correlation with the lateral-displacement capacities of the RC columns according to an energy-based method. Three empirical models were developed. The first was for predicting the cross-sectional area reduction of reinforcement bars according to the initial corrosion crack widths. The second model was for predicting the percentage of energy capacity of RC columns as a function of the drift ratio and corrosion levels. The third model was for predicting the seismic performance levels of RC columns as a function of the initial corrosion crack widths and was used for an in situ structural assessment. The experimental test results showed that above a 2% drift ratio, all uncorroded RC columns (regardless of the concrete strength levels) exhibited a sudden reduction in energy capacity, and their total energy capacity was consumed. In the case of corrosion, the energy capacity of concrete with high strength levels was prematurely exhausted above a 1.4% drift ratio because of the effects of the corrosion products under the high strength levels of the concrete.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2018Korozyon Etkisine Maruz Bırakılmış Betonarme Kirişlerin Eğilme Davranışı
Yalciner, Hakan; Ertuç, İbrahim; Kumbasaroglu, Atila
Korozyona maruz kalmış betonarme yapılarının deprem performanslarının daha doğru bir şekilde değerlendirilmesi için yeni yöntem ve deneysel sonuçlardan elde edilecek verilere ihtiyaç duyulmaktadır. Korozyon beton içerisinde paslanan betonarme donatısının kesit alanının azalmasına neden olurken beraberinde aderans kaybı gibi önemli sorunlara da neden olmaktadır. Aderans kaybı ise donatı sıyrılmasına sebebiyet vererek ek yanal deplasmanların oluşmasına neden olabilmektedir. Ancak mevcut alan yazında literatürde tam ölçekli paslandırılmış betonarme elemanları üzerine yeterli deneysel veriler olmadığından korozyonun etkisi yapı performansı değerlendirmelerinde yalnızca donatı çapındaki azalma olarak alınmaya devam etmektedir. Bu çalışmada tam ölçekli betonarme kirişleri farklı pas oranlarında eğilme deneylerine tabi tutularak mevcut alan yazına veri sağlanması amaçlanmıştır deneysel elde edilen yük-deplasman ilişkileri; artan korozyon oranı, donatı çapındaki azalma, hızlandırılmış korozyon yöntemi sırasında meydana gelen birincil çatlaklar, donatı üzerindeki nervürlerin hasar görmesi ve buna bağlı olarak radyal sürtünme kuvvetindeki azalımın neden olduğu aderans kayıpları gibi parametreler açısından tartışılmıştır. Beş adet betonarme kirişi hızlandırılmış korozyon yöntemi kullanılarak paslandırılmıştır. Betonarme kirişlerindeki gerçek korozyon oranları eğilme deneylerinden sonra betonarme kirişlerinin kırılarak ve içerlerinden betonarme donatılarının çıkartılması ile elde edilmiştir. Yapılan deneysel çalışma sonucunda korozyon oranının %3 değerlerinde yapı elemanlarında sünekliği arttığı ancak artan korozyon oranına bağlı olarak nihai yük taşıma ve süneklik değerlerinde azalmalara sebebiyet verdiği bulunmuştur. Aynı korozyon oranına sahip iki farklı betonarme kirişindeki eğilme davranışlarının farklılığı, sargı donatılarındaki farklı korozyon oranları ile tespit edilmiştir. Elde edilen deney sonuçları, korozyona maruz kalmış betonarme yapılarda aynı korozyon oranı kabulü yerine korozyon haritalandırma yöntemlerinin mevcut yapıların daha doğru değerlendirilmesi için geliştirilmesi gerektiğini ortaya koymuştur.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2018Effects of Geo-grid and Conventional Stirrups on Reinforced Concrete Beams With Polypropylene Fibers
Yalciner, Hakan; Kumbasaroglu, Atila; Ergun, Ugurcan
The aim of the present study was to investigate the effects of different confinement techniques (i.e., conventional shear reinforcement bars and confinement provided by a geo-grid) on flexural strength of full scaled reinforced concrete beams with and without the use of polypropylene fibers. Few studies have been performed using the geo-grids as shear reinforcement bars, and these were limited by flexural strength tests with scaled structural members. Meanwhile, no study has been performed that elucidates the contribution of geo-grids on bond-slip relationships. This is the subject of the present study. Fifteen reinforced concrete beams were tested under static bending tests for different scenarios. The effects of plastic fibers were examined for flexural strength, energy absorption capacities, bond-slip, and moment-curvature relationships for two different confinement techniques. The test results indicated that the use of geo-grids as a shear reinforcement in the available literature does not show good agreement in terms of performance provided by conventional stirrups. The performance of geo-grids as a shear reinforcement was limited with the use of a greater amount of plastic fibers.
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