The use of environmentally friendly materials is becoming increasingly important in order to increase sustainability and reduce carbon emissions in reinforced concrete structures. In this context, glass fiber-reinforced polymer (GFRP) bars, which are proposed as an alternative to traditional steel reinforcements, are attracting attention in engineering applications thanks to their advantages, such as high corrosion resistance, low weight, and electromagnetic permeability. However, the lower elasticity modulus of GFRP reinforcement compared to steel causes greater displacement and crack width under bending and shear effects, leading to certain limitations in structural performance. Due to the limited number of comprehensive analyses in the literature that simultaneously consider parameters such as reinforcement diameter, concrete strength, and stirrup spacing, this study aims to reveal the interactive effects of these parameters through numerical analyses and contribute to existing research. In this context, beam models using GFRP reinforcements with diameters of 10 mm and 12 mm, concrete strengths of 25 MPa and 40 MPa, and different stirrup spacings were analyzed using the ABAQUS (2022) software with a three-dimensional nonlinear finite element method.

The high performance of reinforced concrete structural elements under the effects of lateral loads such as earthquakes is of great importance in terms of minimizing the loss of life and property that may occur due to earthquakes. One of the parameters affecting the earthquake behavior of a reinforced concrete structure is the corrosion effect. The aim of this study is to investigate the behavior of reinforced concrete columns exposed to different corrosion levels for different durations within the damage limits. In this direction, it is aimed to perform linear and nonlinear analysis of reinforced concrete columns in 5 different corrosion scenarios. In the study, nonlinear analyzes of the column were made using ANSYS software, the data obtained were determined for different damage limit levels and compared with the section analysis. Because of the study, moment-curvature relations, lateral load-horizontal displacement relations, bending ductility and plastic rotation capacity of the reinforced concrete column were determined for each corrosion scenario.

Bu çalışmada betonarme binalarda perdelerin kullanılması ve bu perdelerin planda farklı olarak yerleştirilmesi sonucu yapı üzerinde oluşan davranış değişiklikleri incelenmiştir. Bu amaç doğrultusunda Sakarya il sınırları içerisinde belirlenen mevcut bir bina ele alınmış, statik ve mimari proje ile yapıya ait zemin etüt raporlarına ulaşılmıştır. Betonarme binanın mevcut durumuna ek olarak perdelerin plandaki yerleşimlerinin farklı olduğu 6 adet durum için İdeCad paket programı kullanılarak sonlu eleman modelleri üretilmiştir. Yapılan modellemelerden bazılarında bodrum kat tamamen perde ile çevrilmiş, bazılarında ise taşıyıcı sistemde perde elemanı kullanılmadan çerçeve sistemler tercih edilmiştir. Çalışmada, mevcut betonarme bina dâhil olmak üzere üretilen 6 adet yapısal model modal analiz yöntemlerinden biri olan mod birleştirme yöntemi kullanılarak analiz edilmiş ve bölgedeki deprem riskine karşı tasarımı en uygun yapıyı tespit etmek amaçlanmıştır. Analiz sonucunda her bir durum için titreşim periyodu, taban kesme kuvveti, yatay yerdeğiştirme, burulma katsayısı, göreli kat ötelemesi ve yapı maliyeti gibi yapısal parametrelerdeki değişim değerlendirilerek deprem riskinin yoğun olduğu bölgelerimizde yapılacak bina türü yapılar için en uygun tasarımın belirlenmesi sağlanmıştır. Çalışmanın sonucunda, bodrum katı tamamen perdelerden oluşan modelde her iki yönde de deprem riskinin en belirgin düzeyde azaldığı ancak yapı maliyetinin buna paralel olarak arttığı tespit edilmiştir. Buna karşılık olarak taşıyıcı sistemi sadece çerçevelerden oluşan modelde ise deprem riskini en aza indirmek için ilave perde sistemlerinin de kullanılmasının zorunluluk oluşturduğu belirlenmiştir.

Fiber-reinforced polymer (FRP) reinforcement has emerged as an important alternative to conventional steel due to its high corrosion resistance and long-term durability. However, studies on the behavior of FRP-reinforced concrete deep beams under shear-dominated conditions remain limited. In this study, the structural behavior of reinforced concrete deep beams strengthened with GFRP and CFRP bars was numerically investigated using the ABAQUS finite element software. A parametric analysis was conducted to evaluate the effects of shear span-to-depth ratio (a/d), concrete compressive strength, tensile reinforcement ratio, and reinforcement type. The results indicate that reducing the a/d ratio from 1.4 to 1.12 increased the maximum load capacity by 37.6% for GFRP beams and 10.0% for CFRP beams, reflecting enhanced arch action. Increasing concrete strength from 25 MPa to 40 MPa led to capacity increases of 64.5% (GFRP) and 41.7% (CFRP), confirming its dominant role. Increasing the reinforcement ratio improved capacity by 6–9% in GFRP systems and over 15% in CFRP systems. CFRP-reinforced beams exhibited 20–55% higher load capacity, while GFRP beams showed greater ultimate displacement (13–18 mm vs. 8–12 mm). Overall, CFRP provides superior strength, whereas GFRP offers enhanced ductility, supporting performance-based design.

Reinforcement corrosion is one of the primary deterioration mechanisms affecting the long-term seismic performance of reinforced concrete (RC) structures. Although the effects of corrosion on individual RC members have been widely investigated, its influence on the cyclic behavior of RC frame systems has received limited attention. This study numerically investigates the seismic response of a single-bay reinforced concrete frame subjected to cyclic lateral loading under various corrosion scenarios. A three-dimensional nonlinear finite element model was developed in ABAQUS, incorporating corrosion-induced effects such as reinforcement cross-sectional loss, degradation of mechanical properties, bond strength deterioration, and concrete softening. The corrosion propagation rate and exposure duration were considered as key parameters, and different corrosion scenarios were comparatively evaluated. The numerical model was validated using an experimentally tested non-corroded reinforced concrete frame subjected to cyclic loading. The results demonstrate that reinforcement corrosion leads to significant degradation in the seismic performance of RC frames. Depending on corrosion severity, reductions of up to approximately 25% in lateral load capacity and up to 27% in both initial stiffness and energy dissipation capacity were observed. The findings further indicate that stiffness- and energy-based performance indicators are more sensitive to corrosion damage than strength-based indicators. The study highlights the importance of explicitly accounting for corrosion effects in the seismic performance assessment of reinforced concrete frame systems and provides a practical numerical framework for evaluating corrosion-induced performance degradation.