Browsing by Author "Yavuz, D."

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Efficient Sizing and Layout Optimization of Truss Benchmark Structures Using Isres Algorithm
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Avcı, M.S.; Yavuz, D.; Ercan, E.; Nuhoğlu, A.
This paper presents a comprehensive investigation into the application of the Improved Stochastic Ranking Evolution Strategy (ISRES) algorithm for the sizing and layout optimization of truss benchmark structures. Truss structures play a crucial role in engineering and architecture, and optimizing their designs can lead to more efficient and cost-effective solutions. The ISRES algorithm, known for its effectiveness in multi-objective optimization, is adapted for the single-objective optimization of truss designs with multiple design constraints. This study encompasses a wide range of truss benchmark structures, including 10-bar, 15-bar, 18-bar, 25-bar, and 72-bar configurations, each subjected to distinct loading conditions and stress constraints. The objective is to minimize the truss weight while ensuring stress and displacement limits are met. Through extensive experimentation, the ISRES algorithm demonstrates its ability to efficiently explore the solution space and converge to optimal solutions for each truss benchmark structure. The algorithm effectively handles the complexity of the problems, which involve numerous design variables, stress constraints, and nodal displacement limits. A comparative analysis is conducted to assess the performance of the ISRES algorithm against other state-of-the-art optimization methods reported in the literature. The comparison evaluates the quality of the solutions and the computational efficiency of each method. Furthermore, the optimized truss designs are subjected to finite element analysis to validate their structural integrity and stability. The verification process confirms that the designs adhere to the imposed constraints, ensuring the safety and reliability of the final truss configurations. The results of this study demonstrate the efficacy of the ISRES algorithm in providing practical and reliable solutions for the sizing and layout optimization of truss benchmark structures. The algorithm’s competitive performance and robustness make it a valuable tool for structural engineers and designers, offering a versatile and powerful approach for complex engineering optimization tasks. Overall, the findings contribute to the advancement of optimization techniques in structural engineering, promoting the development of more efficient and cost-effective truss designs for a wide range of engineering and architectural applications. The study’s insights empower practitioners to make informed decisions in selecting appropriate optimization strategies for complex truss-design scenarios, fostering advancements in structural engineering and sustainable design practices. © 2024 by the authors.
Enhancing Concrete Performance Through Sustainable Utilization of Class-C and Class-F Fly Ash: a Comprehensive Review
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Akbulut, Z.F.; Yavuz, D.; Tawfik, T.A.; Smarzewski, P.; Guler, S.
Integrating class-C and class-F fly ash (FA) as supplementary cementitious materials (SCMs) in concrete offers a promising pathway for sustainable construction practices. This study explores the pivotal role of FA in reducing carbon dioxide (CO2) emissions and improving concrete’s durability and mechanical properties through a comprehensive life cycle analysis (LCA). By blending FA with cement, significant reductions in CO2 emissions are achieved, alongside enhancements in the workability, compressive strength, and permeability resistance of the concrete matrix. This research elucidates the pozzolanic reaction between FA and calcium hydroxide (CH) during cement hydration, highlighting its contribution to concrete strength and durability. Through a range of comprehensive analysis techniques, including mechanical testing and environmental impact assessment, this study demonstrates the substantial benefits of prioritizing the utilization of class-C and class-F FA in sustainable construction. The findings underscore the industry’s commitment to environmentally conscious practices, promoting structural integrity and reducing ecological impacts. Overall, this research emphasizes class-C and class-F FA as critical components in achieving sustainable construction goals and advancing towards a more environmentally responsible built environment. © 2024 by the authors.
Examining the Workability, Mechanical, and Thermal Characteristics of Eco-Friendly, Structural Self-Compacting Lightweight Concrete Enhanced With Fly Ash and Silica Fume
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Akbulut, Z.F.; Yavuz, D.; Tawfik, T.A.; Smarzewski, P.; Guler, S.
This study compares the workability, mechanical, and thermal characteristics of structural self-compacting lightweight concrete (SCLWC) formulations using pumice aggregate (PA), expanded perlite aggregate (EPA), fly ash (FA), and silica fume (SF). FA and SF were used as partial substitutes for cement at a 10% ratio in various mixes, impacting different aspects: According to the obtained results, FA enhanced the workability but SF reduced it, while SF improved the compressive and splitting tensile strengths more than FA. EPA, used as a fine aggregate alongside PA, decreased the workability, compressive strength, and splitting tensile strength compared to the control mix (K0). The thermal properties were altered by FA and SF similarly, while EPA notably reduced the thermal conductivity coefficients. The thermal conductivity coefficients (TCCs) of the K0–K4 SCLWC mixtures ranged from 0.275 to 0.364 W/mK. K0 had a TCC of 0.364 W/mK. With 10% FA, K1 achieved 0.305 W/mK; K2 with 10% SF reached 0.325 W/mK. K3 and K4, using EPA instead of PA, showed significantly lower TCC values: 0.275 W/mK and 0.289 W/mK, respectively. FA and SF improved the thermal conductivity compared to K0, while EPA further reduced the TCC values in K3 and K4 compared to K1 and K2. The compressive strength (CS) values of the K0–K4 SCLWC mixtures at 7 and 28 days reveal notable trends. Using 10% FA in K1 decreased the CS at both 7 days (12.16 MPa) and 28 days (22.36 MPa), attributed to FA’s gradual pozzolanic activity. Conversely, K2 with SF showed increased CS at 7 days (17.88 MPa) and 28 days (29.89 MPa) due to SF’s rapid pozzolanic activity. Incorporating EPA into K3 and K4 reduced the CS values compared to PA, indicating EPA’s lower strength contribution due to its porous structure. © 2024 by the authors.
An Experimental Investigation of Hydraulic and Early and Later-Age Mechanical Properties of Eco-Friendly Porous Concrete Containing Waste Glass Powder and Fly Ash
(Elsevier Ltd, 2024) Yavuz, D.; Akbulut, Z.F.; Guler, S.
Porous concrete (PC) is a special concrete that contains interconnected large voids, unlike traditional concrete. Coarse aggregate and a minimal fine aggregate are used in the PC composition, thus providing more air and water permeability than conventional concrete. Thanks to the high permeability feature of PC, the natural water cycle is preserved, and rainwater meets groundwater. However, since PC is porous due to its cavity structure, its compressive strength is generally lower, and its durability properties are weaker than conventional concrete. Although fly ash (FA) and waste glass powder (WGP) adversely affect the permeability properties of PCs, they can significantly improve their strength and durability properties. This study examined the effects of FA and WGP on PC's hydraulic and mechanical properties. As a result of the study, we obtained FA- and WGP-added PC samples' hardened density (HD), apparent porosity (AP), water permeability coefficient (k), compressive, splitting tensile, and flexural strengths. The image analysis was also used to determine the FA- and WGP-added PC sample's gap sizes. According to the results obtained, the FA and WGP filled the gaps in the interior structure of the PC by showing a filler effect and, as a result, reduced the AP and k values of the PC. However, FA and WGP significantly increased the compressive, splitting tensile and flexural strength capacities of PC, especially in older ages, due to the progression of hydration, thanks to the calcium-silicate-hydrate (C-S-H) bonds they constituted in the PC matrix and their high pozzolanic activities. © 2024 Elsevier Ltd
Porous Concrete Modification With Silica Fume and Ground Granulated Blast Furnace Slag: Hydraulic and Mechanical Properties Before and After Freeze-Thaw Exposure
(Elsevier Ltd, 2024) Yavuz, D.; Akbulut, Z.F.; Guler, S.
This study investigates the effects of incorporating silica fume (SF) and ground granulated blast furnace slag (GBFS), both individually and in hybrid combinations, on various properties of porous concrete (PC) were evaluated under room conditions and after freeze-thaw (F-T) cycles. The hardened density (HD), water permeability coefficient (k), apparent porosity (AP), as well as compressive strength (CS), splitting tensile strength (STS), and flexural strength (FS) at 7, 28, and 120 days. Additionally, the impact of SF and GBFS on the mass loss (ML), residual compressive strength (RCS), residual splitting tensile strength (RSTS), and residual flexural strength (RFS) of PC samples subjected to 30, 60, 120, and 180 freeze-thaw (F-T) cycles was analyzed. The findings revealed that the addition of SF and GBFS decreased the AP and k values of PC samples under room conditions. Furthermore, these materials significantly improved the CS, STS, and FS properties of PC samples, especially at the 28-day and 120-day marks, owing to their enhanced pozzolanic activity over time. SF and GBFS also contributed to higher RCS, RSTS, and RFS values in PC samples after F-T cycles compared to the control samples. This was due to their effective gap-filling properties and the formation of additional calcium-silicate-hydrate (C-S-H) gels within the matrix. Additionally, SF and GBFS led to slightly higher RDME values in the C1-C6 samples than in the control samples following F-T cycles. However, SF and GBFS did not have a significant impact on reducing the ML values of PC samples after F-T cycles. © 2024 Elsevier Ltd
Post-Cracking Behavior of Hybrid Fiber-Reinforced Concrete-Filled Steel Tube Beams
(Elsevier Ltd, 2019) Guler, S.; Yavuz, D.
The main purpose of this study was to examine the moment, ductility and toughness capacities of steel and hybrid (steel + synthetic) fiber-reinforced concrete (FRC)-filled square aluminum (AL), carbon steel (CS) and stainless steel (SS) tube beams subjected to four-point-in-plane bending. A total of 9 hollow, 18 plain and 72 steel and hybrid FRC-filled AL, CS, and SS beams were tested under four-point-bending until failure. The effects of the steel tube thickness (2, 3 and 4 mm), fiber type (steel and hybrid), fiber volume ratio (0.5% and 1.5%), and the compressive strength of concrete (30 and 70 MPa) on the moment, ductility and flexural toughness capacity of low- and high-strength steel and hybrid FRC-filled AL, CS and SS beams were examined. The results showed that while the steel and hybrid fibers considerably increased the ductility and toughness capacities of the AL, CS and SS beams, they did not significantly contribute to their moment capacities. When compared to plain concrete filled AL, CS and SS beams, although the greatest increase in the moment capacities of the 1.5% steel and hybrid FRC-filled AL, CS and SS beams were only 7.65%, 2.88%, 2.28% and 9.12%, 3.68%, 12.1%, respectively for 70 MPa compressive strength of concrete, the increase in ductility capacities of these beams were 26.6%, 64.3%, 95.2% and 29.9%, 85.9%, 98.9%, respectively. Furthermore, the increase in pre-peak and post-peak energy absorption capacities of 1.5% steel and hybrid FRC-filled AL, CS, and SS beams were obtained as 28.04%, 36.45%, 41% and 124.31%, 214.9%, 359.76%, respectively for 70 MPa compressive strength of concrete. © 2019 Elsevier Ltd