Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Comparison of Aluminum Composite Sandwich and Traditional Reinforced Concrete Slab Frame Systems in Terms of Dynamic and Global Behavior
Demirağ, Özgül; Öztekin, Ertekin
The high mass of traditional reinforced concrete (RC) slabs significantly increases seismic forces in buildings. While lightweight aluminum foam sandwich (AFS) composite slabs offer radical mass reduction, their global seismic performance and interaction with diaphragm flexibility in RC frames remain underexplored. This study presents a linear elastic comparative analysis of pure RC moment frames (1–6 stories), contrasting traditional slabs with AFS slabs under both rigid and semi-rigid diaphragm assumptions. All models were optimally designed to meet identical Eurocode serviceability and stability limits, ensuring a fair comparison via response spectrum analysis. Results show that AFS slabs reduce total structural weight by 33.5–45.9%. This mass reduction, combined with period elongation in semi-rigid models, substantially decreases elastic seismic demands: story shear forces are reduced by 30.9–45.1% for rigid-diaphragm models and by up to 64.3% for semi-rigid ones, while column axial loads decrease by up to 33.7%. All systems satisfied code drift and stability criteria. It is concluded that AFS slabs can dramatically lower seismic mass and elastic force demands while maintaining serviceability, with semi-rigid action providing additional reductions. These conclusions are derived from linear elastic analysis and are applicable to pure frame systems; nonlinear performance and behavior in dual systems require future investigation.
- MakaleYalnız künye2024Theoretical analysis of stress-strain behavior of multi-layer RC beams under flexure
Öztekin, Ertekin
In this study, obtaining theoretical stress-strain curves and determining the parameters defining the equivalent rectangular stress block were aimed for 3 and 4-layered rectangular Reinforced Concrete (RC) cross-sections subjected to flexure. For these aims, the analytical stress-strain model proposed by Hognestad was chosen for the concrete grades (20 MPa ≤ fck≤60 MPa) used in this study. The tensile strength of the concrete was neglected and the thickness of the concrete layers in the compression zone of the concrete cross-section was taken as equal. In addition, while concrete strength was kept constant within each layer, concrete strengths belonging to separate layers were increased from the neutral axis towards the outer face of the compression zone of the concrete cross-section. After the equivalent rectangular stress block parameters were determined by numerical iterations, variations of these parameters depending on concrete strength in layers and layer numbers were obtained. Finally, some analytical equations have been proposed to predict the equivalent stress block parameters for the 3 and 4-layered RC cross-sections and validities of these proposed equations were shown by different metrics in this study.
- MakaleAçık Erişim2023Shear strength estimations and shear designs on RC beams with limited ductility by FL and FIL methods; [BM ve BTM yöntemleri ile sınırlı sünekliğe sahip betonarme kirişlerde kesme dayanımı tahmini ve kesme tasarımı]
Öztekin, Ertekin
In this study, a fuzzy logic model was constituted by using the Fuzzy Logic (FL) method, which is one of the traditional artificial intelligence (AI) methods, in order to estimate the shear strength of reinforced concrete (RC) beams with limited ductility. In this model, beam width(bw), beam height(h), characteristic concrete compressive strength(fck), transverse reinforcement diameter(ØT), the number of arms bearing the shear force of the transverse reinforcement(n) and transverse reinforcement spacing(s) were taken into account as variable parameters. The model developed by using the problem data containing the solutions of shear force strength of 2640 beams with different cross-section properties were tested with 480 beam solutions different from these data. In the tests of the developed FL model, maximum percentage error, minimum percentage error, average percentage error and correlation coefficient values were obtained as 3.604,-0.091, 1.514 and R2=0.999678. By applying the fuzzy inverse logic method (FIL), which was recently developed by the author of this study, on the FL model, which is seen to have been developed quite sensitively from the test results, a total of 521 designs were obtained for 15 different RC beams with limited ductility subjected to shear. In order to check the accuracy of these designs, after shear strengths were obtained by conventional computations for these designs, % error and correlation coefficients were computed between the obtained strength values and the shear force values taken into account for the design. The promising results show that the FIL method can be used in the design of RC beams under shear force and even in other scientific studies such as design, optimization and control.
- MakaleAçık Erişim2021Fuzzy inverse logic: part-2. validation and evaluation of the method; [Bulanık ters mantık: kısım-2. yöntemin doğrulanması ve değerlendirilmesi]
Öztekin, Ertekin
In the first part of this study, which consists of two parts, the introduction of the fuzzy inverse logic method, its foundations, computation and process flow and details were given. In this second part, the method was applied on a very simple mathematical problem and on a simple civil engineering design problem in order to investigate and evaluate the validity of the method easily. Fuzzy inverse logic computations have been carried out on these two simple problems for different dimension, sensitivity and acceptable error values. By comparing the obtained results with the desired outputs and mathematical results, the effective computation ability of the method was tried to be revealed. As a result, it is understood that the method developed in this study has many promising aspects in terms of theoretical computations and practical applications and can be used effectively in many scientific fields.
- MakaleAçık Erişim2021Fuzzy inverse logic: part-1. introduction and bases; [Bulanık ters mantık: kısım-1. giriş ve temeller]
Öztekin, Ertekin
In almost all deterministic and artificial intelligence techniques, for the solution of the scientific problems such as design and control problems, the output estimations are performed depending on manuplations on the values of input variables. With the other words, lots of different values derived from input parameters are tried in order to obtain desired output(s). Contrary to these conventional estimation methods, this study consists of two parts in which a new artificial intelligence method called fuzzy inverse logic(FIL) is developed to determine or estimate the value of the input parameters that give the targeted problem output. In the first part of this study, after providing a brief overview about the method of classical fuzzy logic(FL), the solution approaches and calculation details about FIL are given. In the second part of the study, fuzzy inverse logic method was used to solve one simple mathematical problem and one simple civil engineering problem. After the validity of the developed method was demonstrated by graphics and tables. some evaluations were made about the method.