Avcı, Hasan; Kucuk, Mesut; Sorkhab, Atabek; Sari, Ali

In this study, the out-of-plane behavior of lateral hollow clay brick (LHCB) infill walls embedded within reinforced concrete beams was experimentally investigated. Within the scope of the study, specimens strengthened with CFRP strips, a polyurea-based sprayed coating, a hybrid CFRP + polyurea system, and vertical aluminum profiles were tested, in addition to reference walls with thin and thick plaster. The out-of-plane behavior of the specimens was compared in terms of maximum load-bearing capacity, initial stiffness, displacement capacity, energy dissipation performance, and failure modes. The experimental results showed that increasing the plaster thickness significantly improved the load-bearing capacity and energy dissipation performance. Although CFRP and CFRP + polyurea hybrid reinforcements increased the maximum load capacity by 110–140%, their energy dissipation capacity remained low due to brittle failure behavior. It was determined that the polyurea coating preserved the surface integrity of the brickwork but limited its ductile behavior. The highest performance was achieved in specimens reinforced with vertical aluminum profiles; this method increased out-of-plane strength by over 220% while increasing energy dissipation capacity by approximately 12 times. Additionally, it was found that the aluminum profiles prevented brittle spalling, enabling the walls to exhibit consistent behavior at high displacement levels.

Cosgun, S.I.; Akcan, M.E.

This study addressed a notable gap in the literature concerning the behavior of eccentrically perforated hollow-section stub columns under eccentric compression loading. Cold-formed steel square hollow-section (SHS) stub columns with nominal dimensions of 100 mm × 100 mm and a length of 410 mm were experimentally tested. The test results of perforated SHS stub columns with nominal wall thicknesses ranging from 2.00 to 5.00 mm were compared with those of nonperforated specimens. During the experimental stages, the formation and progression of local buckling in all test specimens were observed using the digital image correlation method. Furthermore, a numerical parameter study was carried out, incorporating different eccentricity values in increments of 25 mm from 0 to 100 mm. The research findings showed that when eccentric flat oval-shaped perforations were formed and a column was subjected to eccentric compression loading, the load-bearing capacity substantially reduced by approximately 75 %–78 %. Finite element analysis (FEA) was comprehensively used as a predictive tool to effectively determine both load-bearing capacities and deformation modes of the SHS stub columns. The strong agreement between the FEA predictions and experimental findings demonstrated the reliability of the method for obtaining the behavior of perforated and nonperforated elements under both axial and eccentric compressive loads in terms of the load-bearing capacity and damage mode. Additionally, the effectiveness of a ring-type hole stiffener was numerically investigated by considering different stiffener thicknesses.

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.

Mercimek, Ömer; Çelik, Alper; Ghoroubi, Rahim; ANIL, Özgür

This study investigates the retrofitting of reinforced concrete columns with TRM strips. Seventeen test specimens were produced, and one was chosen as a reference test specimen. Damaged by loading up to 50% of their maximum axial load-carrying capacity test specimens were retrofitted with two different carbon textiles. In addition to the textile type, TRM strip width, strip spacing, and the use of anchors were determined as experimental variables. Maximum bearing capacity, displacement at bearing capacity, initial stiffness, displacement ductility ratio, and energy consumption capacity were calculated using the axial load-displacement graphs obtained from the experimental study. Depending on the obtained results, the effects of experimental variables on the behavior of damaged reinforced concrete columns were interpreted and compared. It has been determined that the retrofitting method presents very successful results. It has been observed that the fan-type anchor, which is rarely used in literature studies, significantly increases the maximum bearing capacity and energy consumption capacity values of test specimens. Finally, the experimental results were compared with those obtained from the numerical models created by the ABAQUS finite element software.

Yalciner, Hakan; Kumbasaroglu, Atila; Turan, Ahmet İhsan

The journal regret to find that [Figure presented] Fig. 8b is not printed in the paper.

Yalciner, Hakan; Turan, Ahmet İhsan; Kumbasaroglu, Atila

The journal regret to find that Fig. 7c is not printed in the paper.

Cosgun, S.I.

Because of aesthetics, economic advantages, easy composite member production and design, and a wide range of standard sizes, hollow sections are commonly utilized in various construction industry applications worldwide, including conventional and unique free-form structures. However, the sections must fulfill more restricted circumstances to avoid early local buckling. The behavior of cold-formed square hollow sections with different wall thicknesses under static and dynamic transverse impact loading was investigated experimentally and numerically in this study. A method that uses rivet nuts is proposed to improve the dominant local buckling behavior, which is observed in the experimental studies and causes a relatively low bending strength, for providing convenience in field applications. The effectiveness of the proposed method is demonstrated experimentally and numerically using finite-element analysis. In addition to conventional measurement techniques, motion analysis is performed using digital image correlation to measure the displacements during static and dynamic tests. With the proposed technique, the local buckling strength of the square hollow sections is increased by 64% under static loading and by approximately 40–85% under dynamic loading compared with standard square hollow sections, respectively. This is due to the internal stiffness plate, steel threaded rods, and rivet nut configuration connecting the flanges and webs of the square hollow section, which ensures load sharing between the section parts. Additionally, steel threaded rods prevent early buckling of the internal stiffness plate. In addition, parametric analysis results show that the thickness of the internal stiffness plate has a negligible effect on the local buckling strength, although the presence of an internal stiffness plate increased the strength. The numerical analysis results indicate that the local buckling behavior of both conventional and improved square hollow specimens can be predicted with acceptable errors in terms of their strength and damage modes using finite-element analysis models.

Cosgun, S.I.

The author regrets that in the section “3.1. Steel material model,” there was an erroneous statement regarding the value D, which was initially mentioned as D = 1.50 × 107 s−1. The correct value is D = 1.05 × 107 s−1. Additionally, in the section “3.4. Selecting the time increment,” there was a mistake in stating the value Δtstable, initially mentioned as Δtstable = 3.185 × 10−7. The correct value is Δtstable = 4.952 × 10−7.

Yılmaz, Mehmet; Dede, Tayfun

Determining the time and cost of activities is one of the most important stages of construction project planning. Measures taken to shorten the time, such as the need for more or more qualified employees, equipment and machinery, increase project direct cost. The process of deciding which option to use in activities with more than one time–cost option has revealed the time–cost trade-off problem which is discrete optimization. Within the scope of this study, the non-dominant sorting (NDS) method is integrated into the Rao-1 and Rao-2 algorithms and applied to small and medium-scale problems. The numerical results show that the NDS-Rao-2 algorithm has found a better result with a significant number of function evaluations compared to algorithms such as PSO, ACO, GA and TLBO used in previous studies. In addition, the NDS-based Rao-2 algorithm not only find optimal /near results, but also suggest more than one pareto result to the decision maker for time–cost trade-off problem. For this reason, the developed multi-objective Rao-2 algorithm can be considered as a very good alternative for time–cost trade-off problems which are combinatorial problems.

Aslay, Semi Emrah; Dede, Tayfun

Studies on the optimization of reinforced concrete structures are mostly carried out in 2D. This situation causes insufficient accurate results to be obtained in the optimization analyses of reinforced concrete (RC) structures. For this reason, studies on the optimization of RC 3D structures have been started in recent years. However, in these studies, real-world structures have not yet been fully used in terms of having RC shear walls Mergos (2021) [1] because real world RC structures mostly consist of not only RC frames, but also reinforced concrete shear walls and frames. In this study, a real-world 3D RC structure is used. The structure used in the numerical application consists of RC shear walls and frames. Cost and design optimization is done automatically on a 3D structure by using a new software ACDOS (Automated Cost and Design Optimization of Structures) developed by the authors using the ETABS-OAPI files into MATLAB programming. As a numerical example, 3D RC structure is optimized with the Jaya algorithm and successful results are obtained.