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Challenge Journal of Structural Mechanics
Number of Followers: 7  Open Access journalISSN (Online) 2149-8024 Published by TULPAR Academic Publishing  [2 journals]
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- Cover & Contents Vol.11 No.1
Authors: Journal Management CJSMEC
PubDate: 2025-03-04
Issue No: Vol. 11, No. 1 (2025)
- Combined effect of rice husk ash and animal bone powder on strength and
permeability of concrete
Authors: Hasnain Mahmud, Towhid Ahmed, Md. Shafiqul Islam
Pages: 1 - 13
Abstract: Concrete is a key component of construction, and its demand is rising quickly along with infrastructural development. Although cement and aggregates are still essential components for making concrete, the production of cement greatly increases CO2 emissions, necessitating the use of substitute materials to lessen the impact on the environment. As partial cement substitutes, rice husk ash (RHA) and animal bone powder (ABP) are viable alternatives. Animal bones, which are especially common in areas with high cattle populations, and rice husks, a byproduct of paddy production, are frequently discarded despite having useful qualities that can be used to improve concrete. With an emphasis on how they affect the material's permeability and strength, this thesis investigates the addition of RHA and ABP to concrete. Different RHA and ABP replacement amounts are examined through controlled experimentation to ascertain how they affect the properties of concrete following a predetermined curing period. The goal of this research is to determine the ideal combination that strikes a balance between environmental advantages and performance. In addition to improving the qualities of concrete, using RHA and ABP helps with waste management and pollution control. This strategy may help with sustainable building methods, reduce CO2 emissions, and encourage efficient use of resources by lowering dependency on conventional cement.
PubDate: 2025-03-04
DOI: 10.20528/cjsmec.2025.01.001
Issue No: Vol. 11, No. 1 (2025)
- Investigation of the effects of re-curing on mechanical properties of
basalt-polypropylene hybrid fiber concretes after exposure to high
temperature
Authors: Yunus Urtekin, Zinnur Çelik
Pages: 14 - 23
Abstract: Fiber reinforced concretes have attracted significant attention in recent decades due to their superior flexural and toughness properties compared to traditional concrete in civil engineering structures. In addition, cementitious materials can undergo significant mechanical deterioration under high temperature. Therefore, the investigation of the properties of FRC for fire-resistant design has become an important research topic in recent years. On the other hand, there is very little research on the repair of FRCs damaged by fire. In this study, high temperature resistance of mixtures prepared using basalt and polypropylene fibers was investigated. In addition, the ability of FRCs exposed to high temperatures to regain their properties by applying water re-curing process was investigated. In this context, ultrasonic pulse velocity (UPV), compressive and flexural strength of FRC series after different stages were investigated. In the use of water curing single basalt fiber, 18.56% and 13.82% increase in relative compressive strength was obtained after 600 °C and 800 °C, respectively. These increase rates were determined as 22.25% and 22.81% in relative flexural strength. Recovery was more significant in the hybrid mixture formed with 0.2% polypropylene fiber. 29.22% and 15.93% recovery was reported in relative compressive strength after 600 °C and 800 °C, respectively. It was determined that re-curing significantly increased the mechanical properties of FRC mixtures.
PubDate: 2025-03-04
DOI: 10.20528/cjsmec.2025.01.002
Issue No: Vol. 11, No. 1 (2025)
- Predicting shear strength in reinforced concrete deep beams through finite
element modeling of diverse concrete materials
Authors: Erkan Polat, Gökhan Karaman
Pages: 24 - 41
Abstract: This study investigates the prediction of the strength of reinforced concrete deep beams, critical components in urban infrastructure, by evaluating their load-carrying capacities through finite element modeling and nonlinear inelastic analyses using LS-DYNA software. Four widely used concrete material models were examined: Mat084/085, Mat159, Mat072R3, and Mat016. Analyses were conducted on two single-span and four double-span beams with varying reinforcement configurations and an aspect ratio of 1.0, based on well-documented experimental setups. Comparative analyses of force-displacement behavior and stress distributions revealed significant differences in shear strength predictions across the models, with Mat159 providing the most accurate results. These findings establish a reliable and cost-effective approach for predicting the capacities of deep beams, reducing reliance on extensive experimental testing. The study contributes valuable insights for improving strength predictions in critical infrastructure applications such as bridges and foundations.
PubDate: 2025-03-04
DOI: 10.20528/cjsmec.2025.01.003
Issue No: Vol. 11, No. 1 (2025)
- Investigating the effects of glass fiber in enhancing concrete pavement
performance
Authors: Fatih İrfan Baş
Pages: 42 - 54
Abstract: Flexible pavements are considered more sustainable than concrete pavements primarily due to the higher long-term maintenance and rehabilitation costs associated with concrete pavements. Concrete pavements possess a higher modulus of elasticity, which allows them to distribute vehicle loads over a larger area, thereby enhancing the strength of the pavement. However, despite this advantage, their flexural strength is relatively low. As a result, there has been a growing focus on research to improve the flexural strength of concrete pavements to increase their overall performance and sustainability. This study aimed to reveal the effects of enhanced mechanical properties of concrete reinforced with glass fiber on concrete pavements, specifically under heavy vehicle loading as in real-world conditions. The impact of glass fiber on the thickness of both the concrete and base layers, as well as the quality of the base layer material and transverse joint spacing, was assessed. For this purpose, 3D finite element models were developed using ANSYS software, considering concrete thicknesses of 100, 150, and 200 mm, glass fiber ratios of 0%, 0.5%, and 1%, base layer elastic moduli of 100, 200, and 300 MPa, and transverse joint spacings of 300, 450, and 600 mm. It was determined that the concrete thickness and the base layer modulus of elasticity were the most influential factors in minimizing flexural stress, total deformation, and equivalent total strain. The glass fiber addition had a more notable impact on maximum principal stress, especially at the 1% ratio, but had a minimal effect on total deformation and strain. Transverse joint spacing had the least effect, although shorter spacings are still recommended to reduce the risk of transverse cracking in stiffer base layers.
PubDate: 2025-03-04
DOI: 10.20528/cjsmec.2025.01.004
Issue No: Vol. 11, No. 1 (2025)
- The mechanical properties of cement mortar reinforced with silica fume
subjected to sulfate and chloride environment
Authors: Sulaiman Al-Safi, Abdulghani Altharehi, Ibrahim A. Alameri, Abdulmalek Al-Jolahy
Pages: 55 - 69
Abstract: This study investigates the effect of incorporating micro-sized silica fume on the mechanical properties and durability of cement mortar when exposed to sulfate and chloride environments. Mortar samples were prepared by replacing cement with micro-sized silica fume in varying proportions of 5%, 10%, 15%, 20%, 25%, 30%, and 35% by weight. The specimens were cured in water and chemically aggressive conditions, including 5% and 10% sodium sulfate solutions, as well as mixtures of 5% and 10% sodium chloride solutions, to simulate real-world exposure to such environments. Experimental results revealed that the addition of silica fume significantly enhanced the mortar's resistance to chemical deterioration caused by sulfates and chlorides. This improvement is attributed to the pozzolanic reaction of silica fume, which contributed to denser microstructures, reduced porosity, and a stronger bond within the matrix. Among the tested proportions, the optimal replacement ratios for achieving the best balance between mechanical strength and durability were identified up to 20%. These findings highlight the efficiency of silica fume as a supplementary cementitious material in mitigating the adverse effects of aggressive chemical agents. Such modifications can be particularly valuable in improving the service life of concrete structures exposed to harsh environmental conditions, enhancing sustainability and cost-effectiveness in construction practices.
PubDate: 2025-03-04
DOI: 10.20528/cjsmec.2025.01.005
Issue No: Vol. 11, No. 1 (2025)
- Cover & Contents Vol.10 No.4
Authors: Journal Management CJSMEC
PubDate: 2024-12-10
Issue No: Vol. 10, No. 4 (2024)
- Structural behavior of ferrocement beams with circular openings
Authors: Yousry B. I. Shaheen, Zeinab A. Etman, Ahmed A. F. Mohamed
Pages: 116 - 137
Abstract: The construction sector is a major contributor to resource consumption and waste generation. Therefore, developing more efficient and sustainable materials and infrastructure is a top priority for achieving the Sustainable Development Goals. This research aims to contribute to this effort by studying the behavior of ferrocement beams with circular openings, with the goal of understanding their behavior under various loads and determining their potential use in designing more resilient and sustainable structures. Fifteen beams with different reinforcement mesh types were subjected to experimental testing under four-point loading, one group serves as the control with conventional reinforcement, while others vary in mesh type and opening configurations. All beams maintained approximately close reinforcement ratios, employing either two layers of welded galvanized steel mesh or a single layer of expanded steel mesh. Using numerical models, all fifteen beams were analyzed with the structural analysis program ANSYS V. 15 to study their non-linear shear behaviors and compare them with experimental data, focusing on load-deflection curves and failure modes. Results show that beams reinforced with expanded steel mesh achieved higher ultimate loads than those with welded mesh, with increases up to 81.59% depending on the opening configuration. However, beams with openings generally exhibited reduced ultimate loads, averaging 26.85% for welded mesh and 32.13% for expanded mesh, compared to beams without openings. Vertical openings, particularly with multiple openings, resulted in significant load decreases.
PubDate: 2024-12-10
DOI: 10.20528/cjsmec.2024.04.001
Issue No: Vol. 10, No. 4 (2024)
- Freeze-thaw and drop-weight impact resistance of fiber-reinforced pervious
concretes produced using recycled pervious concrete aggregate
Authors: Demet Yavuz
Pages: 138 - 148
Abstract: Pervious concrete can rapidly drain stormwater from the top layer to the sublayer. However, the porous structure of this concrete also results in low mechanical properties, which prevent the widespread use of pervious concrete around the world. This study investigated the freeze-thaw and drop-weight resistances of pervious concrete produced with recycled pervious concrete aggregate. Two different aggregate types (limestone and recycled) and two different aggregate size fractions (15/25 mm and 5/15 mm) were used to examine the effect of aggregate type and gradation. Additionally, for improving mechanical and durability properties, polypropylene fibers were used at three different dosages by the volume of mixtures (0.1%, 0.2%, and 0.3%). Within the scope of the study, compressive, splitting-tensile, and flexural strengths, effective porosity, freeze-thaw, abrasion, and impact resistance of pervious concrete were determined. The results showed that concrete produced with recycled aggregate had some advantages in terms of porosity; however, its mechanical properties, freeze-thaw, and impact resistance were lower than those of pervious concretes produced with limestone aggregate. Additionally, fiber addition decreased the compressive strength and effective porosity of pervious concrete. However, up to a certain point (0.2%), fiber addition improved abrasion, freeze-thaw, and impact resistance, as well as splitting tensile and flexural behavior of pervious concrete.
PubDate: 2024-12-10
DOI: 10.20528/cjsmec.2024.04.002
Issue No: Vol. 10, No. 4 (2024)
- Impact of iron powder and blast furnace slag on the mechanical properties
of polymer concrete: An experimental and hyperparameter-tuned ANN-based
study
Authors: Arif Ulu, Ali Ikbal Tutar, Mohsen Shams, Ferit Cakir
Pages: 149 - 158
Abstract: Polymer-based materials have become increasingly used in concrete production and various engineering applications due to their versatile properties. In particular, polymer concrete (PC) has become a preferred reinforcement material in the construction industry. Various studies have been carried out to evaluate the performance of PC and to improve its mechanical properties by adding different admixtures. This study investigates the effects of fine materials such as iron powder (IP) and blast furnace slag (BFS) on the mechanical performance of PC. Within the scope of the study, samples with 5% and 10% IP, 5% and 10% BFS, 2.5% IP + 2.5% BFS and 5% IP + 5% BFS were prepared. These specimens were cured in the same laboratory environment and subjected to mechanical tests at the end of the 7th day. The results of the mechanical tests were compared to reveal the effect of fine materials on the performance of the PC. The potential of an artificial neural network (ANN) model is investigated to replicate real-world outcomes. The findings provide valuable insights into the potential of iron powder and blast furnace slag as admixtures to improve the mechanical properties of PC.
PubDate: 2024-12-10
DOI: 10.20528/cjsmec.2024.04.003
Issue No: Vol. 10, No. 4 (2024)
- Mechanical properties of lightweight photocatalytic marbelite
Authors: Serdal Ünal, Mehmet Canbaz
Pages: 159 - 165
Abstract: This study investigated the mechanical performance of lightweight photocatalytic marbelite (LPM). In the production of LPM, titanium dioxide (TiO2) and various fiber additives were used to impart self-cleaning properties to the LPM with photocatalytic effect. In the study, fibers were added to the LPM mix at different ratios (0%, 0.5%, 1%) and unit weight, ultrasound transmission rate, bending, splitting tensile and compressive strength tests were carried out on these specimens. The mixture was prepared with perlite and polyester resin and enriched with TiO2 and fiber additives. Perlite was used as an aggregate in the LPM and lightweighting properties were added to the specimens. The experimental results show that increasing the fiber content significantly improves the mechanical strength of the LPM. The improvement in bending strength reached 60%, while in compressive strength it reached 25% and in splitting tensile strength it reached 35%. With the addition of TiO2, the bending strength of LPM increased by 15%, while the compressive strength increased by 12% and the splitting tensile strength increased by 7%. These ratios were higher with increasing fiber content. These results suggest that LPM, which provide environmental benefits with their photocatalytic properties and improved mechanical performance, can be more effectively used in industrial applications.
PubDate: 2024-12-10
DOI: 10.20528/cjsmec.2024.04.004
Issue No: Vol. 10, No. 4 (2024)
- Cover & Contents Vol.10 No.3
Authors: Journal Management CJSMEC
PubDate: 2024-09-17
Issue No: Vol. 10, No. 3 (2024)
- Prediction of optimum design of welded beam design via machine learning
Authors: Yaren Aydın, Farnaz Ahadian, Gebrail Bekdaş, Sinan Melih Nigdeli
Pages: 86 - 94
Abstract: Design optimization is an important engineering design topic. One of the important issues in structural design is to minimize the cost. This study based on an engineering problem of Welded Beam Design aims to minimize the cost of the beam with machine learning (ML) models depending on the constraints on applied load, shear stress, bending stress and end deflection. The data set to be used in this context was created using a metaheuristic optimization algorithm. This hybrid algorithm is based on the classical Jaya algorithm by adding the student phase of Teaching Learning Based Optimization. The dataset obtained as a result of the optimization is a dataset with 1189 rows. Six different algorithms were used for prediction analyses. These are Linear Regression, Decision Tree, Elastic Net, K-Nearest Neighbour, Random Forest, and XGBoost algorithm. In the data set, load, length, and displacement are input; the design variables such as b, h, l, t and minimum cost are output. Since there is more than one output in the dataset, Multioutput Regression is applied. The performance of regression models was assessed using the Coefficient of Determination (R²), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE). According to the results obtained, the Decision Tree Model showed the best performance among the other models (R2=1, MAE=6.13e-11, RMSE=9.47e-10).
PubDate: 2024-09-17
DOI: 10.20528/cjsmec.2024.03.001
Issue No: Vol. 10, No. 3 (2024)
- The effect of build direction on component strength in SLA-based additive
manufacturing
Authors: Hojjat Ghahramanzadeh Asl, Derya Karaman
Pages: 95 - 100
Abstract: Nowadays additive manufacturing is frequently used, especially in industrial applications such as aerospace and biomedical. In the additive manufacturing method, thanks to the layered manufacturing technique, it enables the production of components with all kinds of complex geometries and accelerates the production process. As it is known, the orientation of the layers in the additive manufacturing technique affects the mechanical properties of the components. Among the parameters affecting strength, layer thickness, production direction and layer geometry are of great importance. In this study, the effect of layer orientation on component strength in SLA-based additive manufacturing was experimentally investigated. Consequently, standard tensile samples were produced at four different production orientation using the UV Stereolithography method. Tests of the tensile samples were carried out at constant tensile speed and tensile curves were obtained. According to the results, it was determined that the layer joints parallel to the shear plane exhibited the lowest strength. Therefore, samples produced at the parallel to the shear plane fractures at lower loads and showed low strength. Considering the experimental results obtained, it has been determined that the structure orientation affects the mechanical properties of the component by ~20%.
PubDate: 2024-09-17
DOI: 10.20528/cjsmec.2024.03.002
Issue No: Vol. 10, No. 3 (2024)
- Influence of the distance between vertical cylinders positioned in a row
on the wind load on them
Authors: Lyubomir A. Zdravkov
Pages: 101 - 108
Abstract: The silos and vertical cylindrical tanks of small volumes are often built in batteries, at short distances between them. As a result of their close location, the wind load on them increases. In the European standard EN 1991-1-4:2005+A1:2010 exists a methodology for determining this increase, which is dependent on the ratio a/d, where a is the distance between the facilities and d is their diameters. Unfortunately, this methodology is applicable for ratios a/d > 2.5. In cases where the values are smaller, the standard transfers to the national annexes. In the available to the author annexes, including the Bulgarian one, there is nothing on the subject. Moreover, the necessary information could not be found in the public scientific literature. Only in the Australian/New Zealand standard AS/NZS 1170.2:2011 are written some simple rules for closely spaced vessels. To fill this gap, multiple models of closely spaced cylindrical bodies has been created by the author. A computer fluid simulation (CFD) program is used for this purpose. In the present study, the bodies are arranged in one row and the wind blows them perpendicularly. Through these computer models is determined how the wind load changes due to their proximity. In contrast to what is stated in EN 1991-1-4:2005+A1:2010, the dependence is not linear, and the influence of the close arrangement of the bodies decays much faster. On the other hand, this influence should be considered at much greater distances between bodies than stated in AS/NZS 1170.2:2011.
PubDate: 2024-09-17
DOI: 10.20528/cjsmec.2024.03.003
Issue No: Vol. 10, No. 3 (2024)
- Optimization of mechanical properties in lime-based composites using the
Taguchi method
Authors: Bekir Güney, Sadık Alper Yıldızel
Pages: 109 - 115
Abstract: Global warming is widely recognized as one of the most pressing issues of our time. One of the primary contributors to this phenomenon is the emission of CO2, which significantly exacerbates global warming. Today, the production and industry of cement stand out as leading sources of carbon emissions. Consequently, the scientific community is actively researching solutions to reduce cement usage. Some of these efforts focus on alternative binders such as silica fumes and lime. In this study, the goal is to enhance silica fume and lime binder composites, optimizing them for both refractory and insulating properties using the Taguchi optimization method. The results indicate significant improvements in compressive and flexural strengths, which were further validated through testing. The highest compressive strength achieved was 11.97 MPa, while the maximum flexural strength reached 0.34 MPa. This research underscores the potential of alternative binders in mitigating the environmental impact of cement production while enhancing material performance in various applications.
PubDate: 2024-09-17
DOI: 10.20528/cjsmec.2024.03.004
Issue No: Vol. 10, No. 3 (2024)
- Cover & Contents Vol.10 No.2
Authors: Journal Management CJSMEC
PubDate: 2024-06-13
Issue No: Vol. 10, No. 2 (2024)
- Ultimate drift ratio prediction of steel plate shear wall systems: a
machine learning approach
Authors: Muhammed Gürbüz, İlker Kazaz
Pages: 34 - 46
Abstract: Predicting the ultimate drift ratio of steel plate shear wall (SPSW) systems is important for ensuring the structural integrity and performance of these systems under lateral loads. In this study, machine learning models are developed for predicting the ultimate drift ratio based on various design parameters using data from previous research on SPSW systems. These design parameters include the panel aspect ratio, column flexibility parameter, axial load ratio, web plate thickness and stiffness of horizontal and vertical boundary elements. A range of machine learning models is considered, including Random Forest, Lasso, Gradient Boosting, XGBoost, Adaboost, Artificial Neural Network and a stacked regressor. The models are trained and evaluated using data from 292 different SPSW models, and their performance is compared based on the R-squared value, root mean squared error (RMSE), and evaluation time. The results of this study demonstrate the effectiveness of machine learning techniques for predicting the ultimate drift ratio of SPSW systems. The results of this study show that machine learning techniques effectively predict the ultimate drift ratio of SPSW systems. Among the models considered, the ANN model achieved the highest R2 value, with a value of 0.94.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.001
Issue No: Vol. 10, No. 2 (2024)
- The novelty design method in lightweight structures with low effective
elastic modulus
Authors: Hojjat Ghahramanzadeh Asl, Derya Karaman
Pages: 47 - 57
Abstract: Lightweight structures are of great interest in industrial areas such as automotive, aerospace, and biomedical due to their lightness, and superior mechanical performance. The advantages of lightweight structures are increased with the spread of additive manufacturing and design them in various geometries. Beam-based structures and triply periodic minimal surface structures are currently used to extend these advantages. In this study, it is aimed to create die models of beam-based structures in order to contribute to the geometric diversity for lightweight structures. By designing the die lattice structures of the beam-based structures, the comparison of the mechanical performance of basic lattice and die lattice structures with the same porosity was carried out. For FCC, CFCC, and Octet-Truss lattice structures, basic lattice and die lattice structures are designed on scaffolds in 5x5x5 array with 50%, 60%, 70%, and 80% porosity. Numerical data were obtained for Ti6Al4V with compression tests simulated by applying pressure in the -y direction. According to numerical analyses, the effective elastic modulus decreased due to the increased porosity in both structure models. The CFCC and Octet Truss scaffolds have different force transmission performances. Likewise, this situation is observed in die lattice structures, but the force transmission with the surfaces reveals the difference of the structures. The effective elastic modulus of basic lattice structure with 80% porosity of the Octet Truss structure is approximately twice that of the die lattice structure. Thus, the use of die lattice structures will provide advantages for the design of lightweight structures with low elastic modulus.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.002
Issue No: Vol. 10, No. 2 (2024)
- Effect of different trimline extension of clear aligners in combination
with Class II elastics on the mandibular dentition: a finite element
analysis
Authors: Nurver Karslı, Bahanur Hilal Kisbet
Pages: 58 - 68
Abstract: Objective of this study is to evaluate the effect of different trimline extension of aligners and the effect of elastics applied through the slit cutouts and buttons on the mandibular dentition using Class II intermaxillary elastics combined with clear aligner treatment. Three-dimensional (3D) finite element models that simulate the effects of Class II elastics on the mandibular arch in four different scenarios were studied, named, straight and high trimline aligner (HTLA) model with elastic applied through buttons (Model 1), straight and low trimline aligner (LTLA) model with elastic applied through buttons (Model 2), HTLA model with elastic applied through slit cutout (Model 3), LTLA model with elastic applied through slit cutout (Model 4). 3D displacements of the teeth, von Mises stress (VMS) in the periodontal ligament (PDL) were calculated. In all models, the crown of the mandibular anterior teeth moved labially, the root moved lingually, and the mandibular first molars moved mesially. Among all models, labialization of incisors and mesialization of molars was highest in Model 2 and lowest in Model 3. In clear aligner treatment combined with Class II elastics, HTLA was more effective in controlling mandibular incisor proclination and mesial tipping of mandibular molars. The slit cutout models were more effective in controlling mesial tipping of mandibular molars.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.003
Issue No: Vol. 10, No. 2 (2024)
- From ruins to reconstruction: Harnessing text-to-image AI for restoring
historical architectures
Authors: Kawsar Arzomand, Michael Rustell, Tatiana Kalganova
Pages: 69 - 85
Abstract: The preservation of cultural heritage has become increasingly important in the face of conflicts and natural disasters that threaten historical sites worldwide. This study explores the application of artificial intelligence (AI), specifically text-to-image generation technologies, in reconstructing heritage sites damaged by these adversities. Utilising detailed textual descriptions and historical records, this study employed AI to produce accurate visual representations of damaged heritage sites, bridging the gap between traditional documentation and modern digital reconstruction methods. This approach not only enhances the architectural design process across various disciplines but also initiates a paradigm shift towards more dynamic, intuitive, and efficient heritage conservation practices. The methodology integrates data collection, iterative AI-generated image production, expert review, and comparative analysis against historical data to evaluate reconstruction accuracy and authenticity. By integrating AI with traditional preservation practices, this study advocates a balanced approach to conserving cultural legacies, ensuring their preservation and revitalisation for future generations. Preliminary findings suggest that AI-generated imagery holds significant promise for enhancing digital heritage preservation by offering novel approaches for visualising and understanding historical sites. These findings also highlight the need to address ethical, technical, and collaborative challenges to enhance the precision, reliability, and applicability of AI technologies in the field of cultural heritage. This study contributes to digital humanities and archaeological conservation, demonstrating AI's potential to support and complement traditional heritage preservation methods and suggests a pathway for substantial methodological evolution in the field.
PubDate: 2024-06-13
DOI: 10.20528/cjsmec.2024.02.004
Issue No: Vol. 10, No. 2 (2024)
- Cover & Contents Vol.10 No.1
Authors: Journal Management CJSMEC
PubDate: 2024-03-09
Issue No: Vol. 10, No. 1 (2024)
- Strengthening of historic masonry vaults with CFRP prepreg
Authors: İsmail Hakkı Tarhan, Habib Uysal
Pages: 1 - 6
Abstract: Masonry vaults, frequently used in historic buildings to create large openings, have played a critical role in the survival of these buildings to the present day. These structural elements, which have been exposed to destructive effects such as earthquakes for centuries, need strengthening activities in order to transfer cultural heritage to future generations. The use of composite materials with high mechanical properties for strengthening purposes has been a popular method since the beginning of the 21st century, and its effectiveness has been proven. In this study, a masonry vault in the historical redoubts located in Erzurum, Türkiye, was modelled, and the effectiveness of various strengthening scenarios using prepreg composites was investigated. Numerical simulations were conducted with the Finite element method-based macro modelling approach. The investigation revealed that retrofitting arrangements maintained the stress distribution in masonry vaults while reducing maximum tensile stress; intrados reinforcement proved more effective, particularly the intrados-straight retrofit, with a 24% improvement, whereas extrados strengthening showed limited effectiveness.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.001
Issue No: Vol. 10, No. 1 (2024)
- Effect of soil types on nonlinear earthquake behavior of buildings
Authors: Memduh Karalar, Murat Demirköse, Necati Mert
Pages: 7 - 13
Abstract: The Winkler method, which is widely used today, assumes that the soil behaves elastically and does not take into account the soil shear stress values, it is insufficient to reflect the actual soil behavior. Especially in the earthquake calculations of rigid and massive structures such as high-rise buildings, dams, suspension bridges, viaducts, it is necessary to consider soil as a dynamic system that changes shape and affects the behavior of the structure in terms of inertia. In response to the effect of soil on the structure, the structure also affects soil both kinematically and dynamically. Thus, in the absence of the structure, the earthquake data, which is only a result of the dynamic behavior of the soil in its internal structure, now acquires a more complex soil motion characteristic that is also affected by the presence of the structure. The observations made in some earthquakes show that the changes between the records taken simultaneously on the building foundation and at soil surface not a point far from foundation, show that the structure also affects soil therefore soil motion in response to the effect of the earthquake on the structure. In this study, the effect of soil types on the nonlinear seismic behavior of reinforced concrete structures was investigated. For this purpose, 7-storey building models with different plans and rigidities were created. The behavior of these models under 11 different earthquake loads for the ZA, ZB, ZC, ZD, ZE soil types specified in the Turkish Building Earthquake Code has been investigated. Analyzes were made using the time history method with the help of the SAP2000 program. As a result of the analysis, the displacements, plastic hinge formation, Effective inter-storey drift and period values obtained for different models were compared.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.002
Issue No: Vol. 10, No. 1 (2024)
- Size effect on compressive behavior of GFRP bars
Authors: Meltem Eryılmaz Yıldırım, Kerem Aybar, Mehmet Canbaz
Pages: 14 - 20
Abstract: In the last three decades, studies investigating the use of Glass Fiber Reinforced Polymer (GFRP) bars as an alternative to conventional steel rebars have increased due to their corrosive resistance. In addition to corrosion resistance, GFRP bars utilize high specific tensile strength, which makes them highly desirable in civil engineering applications. However, major design guidelines for GFRP-reinforced concrete structures currently do not consider their compressive contribution. Nevertheless, there is a growing trend in utilizing GFRP bars as compressive elements, driven by various studies demonstrating their ability to bear compressive loads effectively. This increasing demand underscores the need to comprehend the mechanical properties of GFRP bars, particularly in terms of their compressive behavior. Furthermore, a standardized test method to evaluate their compressive properties has not yet been developed. Addressing these gaps, this research paper focuses on investigating the influence of specimen size on the compressive strength of GFRP bars, specifically emphasizing on the compressive properties of GFRP bars. Compressive tests were conducted on GFRP specimens with varying diameters while maintaining a constant slenderness ratio. The findings from these compression tests shed light on the critical role of size in the compressive behavior of GFRP. This research emphasizes the importance of considering size as a significant parameter in designing mechanical properties for GFRP reinforcements.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.003
Issue No: Vol. 10, No. 1 (2024)
- Structural behavior of historical Obruk Inn under different earthquakes
Authors: Süleyman Kamil Akın, Ahmet Alagöz
Pages: 21 - 33
Abstract: Masonry structures is one of the most preferred structure types throughout history. The advantageous of these structures can be categorized as longevity, affordability and easy access to materials. Due to a lack of information and constructive errors, masonry structures suffer major damage under effect of earthquakes. While the vertical load carrying capacity of a masonry structure is excellent, its performance under horizontal loads is very poor. The brittle behavior of masonry structures, in particular, causes the structure to suffer significant damage or collapse completely during an earthquake. Türkiye is situated over a major earthquake zone. Throughout history, there has been numerous major earthquakes. These earthquakes have demolished the masonry structures resulted in significant life and economic losses. Therefore, in recent days, the examination of the seismic resilience performance of masonry structures as well as the required strengthening have become a pivotal issue. Thus, the aim of this study is to analyze the seismic performance of historical Obruk Inn subjected to different earthquake effects via finite elements method (FEM). To do this, the plans obtained from on-site inspections for historical Obruk Inn to create structural FEM model and its performance was evaluated under the influence of various earthquake excitations. As a result of the analyses, it was determined that the historical Obruk Inn structure should have immediate be strengthened against a possible earthquake.
PubDate: 2024-03-09
DOI: 10.20528/cjsmec.2024.01.004
Issue No: Vol. 10, No. 1 (2024)
