Journal of Structural Engineering & Applied Mechanics
İbrahim Özgür Dedeoğlu
Mosques and masjids are the most important parts of Islamic culture in terms of their architectural and structural characteristics. These structures also provide an important insight into the construction techniques and historical process of the region in which they were built. Many of these structures are still in use around the world. However, most historical mosques and masjids are vulnerable to earthquakes or are not strong enough. Therefore, it is important to know the risk status of these important structures with respect to earthquake forces and to carry out the necessary strengthening works. In this study, the performance of the historical Ahi Musa Masjid (built in 1185) was investigated using the linear earthquake solution method, which provides a practical approach to determining the earthquake performance of historical structures. Firstly, studies were carried out to determine the geometric and material properties of the historical Masjid. A finite element model of the historical Masjid was then constructed and linear performance analyses were performed under vertical loads and equivalent earthquake loads. As a result of the analyses, the displacement ratios, compressive and shear stresses of the historical Masjid were obtained and evaluated according to the collapse prevention performance level for the earthquake level DD-3, which is one of the performance levels recommended for historical structures of local importance in the Guidelines for the Management of Earthquake Risks for Historical Structures. The aforementioned stress and drift ratio values remained below the reference values. In conclusion, the Masjid will safely withstand the potential effects of an earthquake.
The response spectra in the seismic design codes guide the seismic design force calculations that are crucial for structural safety and construction costs. In general, they are determined by crisp logic-based numerical classifications of seismic parameters, which primarily affect the shape and values of the spectrum. Crisp logic response spectra generation may have limitations in the accurate determination of relevant parameters. In this paper, a fuzzy inference system (FIS) rule-based model is proposed to address this issue. The proposed model uses spectral acceleration coefficients and shear wave velocity as inputs to generate the site coefficients of the response spectra according to the Türkiye Building Earthquake Code (TBEC 2018). The FIS model spectra generation is compared with the crisp logic model for thirty-five examples, and the model performance is evaluated. The study demonstrates significant differences between the two models in terms of the response spectra' shape and acceleration spectrum intensity values, but the FIS model provides comparatively better accuracy in response spectra generation. The proposed model can be modified and applied to various parameters for generating response spectra in different seismic design codes with the exposition of fuzzy logic rules that show the concerned problem's internal working mechanism.
Mehmet Fatih Yılmaz
Abdulkadir Cüneyt Aydın
One of the most widely utilized methods for determining seismic performance and allowing additional study is fragility analysis. The fragility curve, which is typically characterized by two-parameter log-normal distribution functions, depicts the probability of bridge components exceeding a certain damage limit. This study examines the fragility analysis of a multi-span continuous (MSC) steel roadway bridge in Türkiye. The probabilistic seismic demand model (PSDMs) is illustrated by conducting many time history analyses (THA). The nonlinear analyses are conducted for sixty earthquakes. Logarithmic regression analyses and fragility curves were derived for varying intensity measures (IM) in terms of efficiency. Monte Carlo analysis was used to derive the system fragility curve of the bridge. The PGA and ASI are the most proper intensity measure for the fragility curve of the bridge. Moreover, the slight damage can be visualized with a higher probability for the small intensity measure that even mild earthquake motion can cause some slight damage on the bridge but after slight damage bridge has further capacity until the collapse damage is visualized.
The SIFCON concrete reinforced with glass-fiber reinforced polymer (GFRP) bars can provide a construction system with high durability and strength. Slurry infiltrated fibrous concrete (SIFCON) is a new type of conventional fiber reinforced concrete. The aim of this paper is to evaluate the flexural and shear behavior of the SIFCON concrete beams reinforced with GFRP bars were evaluated under four-point bending and three-point shear tests. The parameters investigated were material type of longitudinal reinforcement (steel and GFRP), transverse reinforcement type (steel and mesh) and mesh reinforcement spacing (25 mm and 12 mm). For this purpose, a total of twelve SIFCON concrete beams with steel and GFRP bar as longitudinal reinforcement measuring 150x150x800 mm were cast. Moreover, stirrup and mesh reinforcement as transverse reinforcement are another main parameter of this study. The test results showed that the effects of longitudinal and transverse reinforcement type and mesh spacing on the strength, crack propagation, and energy dissipation capacity of RC beams under bending and shear were experimentally investigated. The use of steel longitudinal reinforcement in both four-point and three-point tests increased the bending moment and shear strength compared to beams with GFRP. Moreover, although the use of mesh reinforcement in reinforced concrete beams under four-point bending reduced the strength, it increased the strength in beams with GFRP. In the samples under the shear force, the use of mesh reinforcement in the steel reinforced group increases the shear strength, but the use of mesh reinforcement in the GFRP group decreases the shear strength.
Stephen Babajide Olabimtan
It is required to help improve concrete's efficiency through the use of waste while also preventing river sand and valuable area from becoming pollution dumpsites. Construction and demolition waste (CDW) has a wide range of possible uses in the construction sector and is quite ubiquitous. It is used as recycled aggregates (RA) in building supplies like mortar and concrete, however, is remaining relatively constrained. This is mostly because it lacks the strength and has more porosity and variability when compared to natural aggregates (NA). Countless research has been conducted with the goal of lowering CO2 emissions, reducing NA exploitation, and enhancing the qualities of these RAs. This research study undertakes a complete experimental assessment to evaluate the impact of adding glass powder and recycled fine aggregates on the creation of sustainable concrete. The study looks at varied proportions of glass powder and recycled fine aggregates, ranging from 0% to 20% with 5% intervals. At a constant temperature of 20°C, the concrete samples are treated to various curing conditions, including both wet and dry curing. Curing times of 3, 7, 14, and 28 days are evaluated. This particular mixture demonstrates a significant increase of 7.2% - 10.76% in strength, indicating that the combined use of 20% GP and 20% RFA results in the highest enhancement of concrete strength among the tested mixtures. This research experiment can be drawn that the inclusion of GP and RFA in concrete gives a tremendous influence in the implementation of mechanical properties and durability for a sustainable concrete.
Seismic design codes define response spectra with crisp numerical classifications of seismic parameters, which mainly affect the spectrum's shape and determination of seismic design loads. The efficiency of structural safety and construction costs depends on the optimum design and accurately determined seismic forces. As presented in the seismic design codes, several parameters are utilized to calculate the seismic design forces with response spectra. This study proposes a rule-based fuzzy inference system (FIS) model with fuzzy set numbers to determine the relevant parameters. By defining the soil profile thickness and shear wave velocity as inputs, the model generates the spectrum characteristic periods specified in the Türkiye Building Earthquake Code (TBEC 2007). The response spectra of twenty different samples with the FIS and crisp models were generated and compared to assess the model's superiority. Unlike crisp seismic code classifications, the proposed FIS model accounts for imperfections in soil group selection and topmost soil layer thickness, offering a more realistic representation of uncertainties and proving to be an effective tool for addressing linguistic vagueness in seismic response spectra analysis. The comparison between fuzzy and crisp output seismic parameters revealed significant differences in response spectra shape and spectrum intensity values. The FIS model-generated spectra were more conservative in certain building locations, while in others, they provided similar or lower values, suggesting potential cost savings in design. The FIS model demonstrates its efficacy in producing more accurate and robust designs by considering the uncertainties inherent in the problem. Furthermore, this approach has the potential to be extended to study seismic parameters of other design codes, although further research is required to comprehensively explore its capabilities and limitations.
Metaheuristic algorithms belong to the category of non-deterministic optimization methods. Extensive research conducted in this domain has elucidated that each of these methods possesses distinctive merits and demerits. To illustrate, one algorithm may exhibit a notable penchant for exploration, whereas another algorithm may demonstrate exceptional prowess in exploitation. The judicious selection of a suitable and efficient algorithm for a given problem can profoundly influence both the rate of convergence and the level of accuracy. Over the past few decades, various swarm-based metaheuristic algorithms have been introduced in technical literature. Consequently, undertaking a comprehensive comparative evaluation of a subset of these methodologies can furnish researchers with an essential framework to discern the most appropriate algorithm for their objectives. The current investigation focuses on evaluating and comparing four swarm-based metaheuristic algorithms especially on solving size optimization of truss structures for this purpose. To cover the research conducted in the past two decades as comprehensively as possible, a hierarchical selection process was employed for choosing the methods. As a result, the following algorithms were chosen Firefly Algorithm (FA), Drosophila Food-search Algorithm (DFO), Harris Hawk Optimization (HHO), and Butterfly Optimization Algorithm (BOA). Various characteristics of the selected algorithms, such as convergence rate, diversity variation, complexity, and accuracy of the final solutions, were compared. The findings indicate Harris Hawk Optimization (HHO) could nearly outperform the other selected methods on solving structural size optimization problems.
Mohammad Manzoor Nasery
When a load is exerted on a structural element several times, it is called repetitive loading. This type of loading causes more damage to structural elements than monotonic loading. This paper presents the effects of repetitive transverse impact loading on the weak axis of rectangular hollow steel section beam. For this purpose, three simply supported beams were tested with a constant drop weight of 75 kg and three different heights (400 mm, 800 mm and 1200 mm). Transverse impact load was exerted on each specimen 3 times repeatedly. In the numerical studies, finite element models of all specimens were developed using ABAQUS finite element analysis software. In order to obtain reliable numerical models, finite element models were verified using the experimental data. To investigate the effects of repetitive transverse impact loading on hollow section steel beam, parameters such as displacement, reaction forces, stress distributions and out of plane plastic denting were evaluated comparatively. The obtained results showed that, when the height value is increased twice as the initial height in test series RIA and RIB, the displacement value increased by 57% in the first hit, 68% in the second hit and 79 % in the third hit. Thus, it seems that the increase in the displacement value due to the increase in the damage of subsequent hits is not linear, but rather logarithmic. Finally, it was understood that with increase in the plastic deformation and displacement occurring in an element subjected to repeated impact loading, a decrement occurs in the reaction force transferred to the supports.