The usage of computer software in civil engineering has expanded in last decades. Many general-purpose and special-purpose commercial programs perform a very important function, especially at the design stage. In this study, a computer program is introduced for the analysis and design of the axial symmetric cylindrical wall con-sidering the dome effects. Analysis processes are carried out according to Flexibility theory with long wall assumption and during the reinforced concrete (RC) design of the wall, ACI 318-Building code requirements for structural concrete are considered. In numerical investigation, the effects of the dome properties (thickness and height) on the analysis and design of the wall are investigated by performing a totally 72 case analyzes. These cases include different support condition at bottom of the wall, wall heights, dome thicknesses and heights. According to analysis results, it is concluded that effects of dome thickness and heights on the wall on the wall are very limited.
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Tuned mass dampers (TMDs) are used to damp vibration of mechanical systems. TMDs are also used on structures to reduce the effects of strong forces such as winds and earthquakes. For the efficiency of TMD, optimization of TMD parameters is needed. Several classical formulations were proposed, but metaheuristic methods are generally used to find the best result. In addition, the metaheuristic based opti-mum results are used in machine learning of artificial intelligence-based models like artificial neural networks (ANN). These ANN models are also used in development of tuning equation via curve fitting. The classical and ANN-based formulations were found according to frequency domain responses. In the present study, the classical and ANN-based formulations were evaluated by comparing on time-history re-sponses of seismic structure. In comparison, near-fault ground motion records in-cluding directivity pulses are used. The ANN based methods have advantages by providing smaller stroke requirement and damping for TMDs.
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The increase in the population day by day and urbanization has led to a rapid increase in the construction sector.With the increase in demand in construction, the product types of building materials are increasing.It is seen that wastes are formed during andafter the production of the materials used in the building. This highlights studies on waste management and recycling of waste.After construction activities, wastes are recycled or converted to secondary products.One of these is wood waste, a tra-ditional building material. In addition to the production of wood furniture, it is used in various areas from the beginning of construction to the end of the building. In this study, sawdust, which is the waste of a woodworking company, was used. Utilizing the advantages of wood, recyclable and sustainable cement bonded wood composite production practices have been explored. It is aimed to produce nature and environ-ment friendly, ecological and economic and durable composite materials. In this re-search, it is aimed to determine the optimum ratio by using different ratios of saw-dust-cement while keeping the water-cement ratio constant in production. The spec-imens taken from the production were exposed to high temperature after gaining strength. The strength results, unit weights and ultrasonic pulse velocityresults of cement bonded wood composite samples exposed to high temperature were exam-ined. Although cement bonded wood composites are exposed to high temperatures such as 400°C, it has been observed that strength is achieved. With this study, an al-ternative area was proposed for the evaluation of these wastes.
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Slope stability analysis is performed in practical geotechnical engineering using the finite element method, which is an advanced method and is widely used by engineers. With the development of computer technology, it has become easy to study the slope's stability supported by frame prestressed anchor and sheet pile wall through the displacement-based finite element numerical analysis method, to calculate the safety factors. However, the expansion angle ψʹ is not widely covered. In this study, PLAXIS two-dimensional finite element method is using to establish the slope model supported by frame prestressed anchor and sheet pile wall, and the influence of ex-pansion angle on slope deformation is studied. The results show that the expansion angle has a differenteffect on the convergence of the two-dimensional slope model. In the model slope, a prestressed frame anchor and sheet pile wall reinforce the slope. The failure mechanisms were unclear when φʹ= ψʹ(flow base). Besides, when the slope has high soil strength parameters (c' or φʹ), the expansion angle will affect the calculation results and convergence. In general, the expansion angle significantly influences the slope's stability and is not affected. Therefore, it was necessary to note the effect of the angle of expansion on stability.
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Electric power systems have critical importance in the sustainability of social life and economy. The past and recent earthquakes showed clearly that these systems have high vulnerability due to earthquakes. In this study, the typical electric power systems which are commonly preferred and located at five different sites in high seismic zone of Turkey, Marmara region, have been examined. In the first part of the study, the earthquake hazard for Marmara region has been accomplished. The earthquake hazard curves at five different sites for two different earthquake levels, and two different site conditions as soft and stiff site classes according to the Turkish Building Seismic Design Code 2018 have been obtained. The seismic vulnerability assessment of substation and distribution circuits for two different design states, namely anchored and unanchored, achieved by the fragility functions. The probability of power outage durations have been evaluated based on the restoration curves. It has been observed that the results obtained within the scope of the study are highly consistent with post-earthquake studies in the literature. The proposed methodology through the power outage graphics enable a quick preliminary evaluation of the power outage based on the current design status and location for any electric power systems in the Marmara region.
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Extended end-plated connections are preferred in moment resisting frames due to their advantages such as no required in-situ welding, accurate fabrication and economic feasibility compared to flange welded moment connections. The capacity of the extended end-plated connections depends on bolt configurations, end-plate thickness, bolt diameter and their material properties excluding column part. The thickness of end-plate can be computed using yield line mechanisms. Different yield line patterns are available in the literature and some of these are adopted in seismic codes to estimate the thickness of end-plate. In this study, the accuracy of different yield line patterns is compared using collected experimental data and numerical analysis. A parametric numerical analysis was conducted utilizing the finite element tool, ABAQUS. The results of experimental data and parametric study were evaluated for both unstiffened and stiffened four bolted extended end-plated connections. The results revealed that the capacity of the end-plate connections significantly depends on the yield line mechanism. Therefore, selecting an accurate yield line mechanism is essential in order not to overestimate the thickness of the end-plate. More importantly is that these yield line mechanisms can be directly implemented to AISC 358 and Turkish Building Earthquake Code 2018 (TBEC-2018).
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The destructive earthquakes and structural damages reveal the importance of the rules of earthquake-resistant structural design. The need of update and renewal of these rules periodically become inevitable as a result of scientific developments, in novations in construction technologies and building materials. Turkey which is an extremely region in terms of seismicity was adapted to these changes through time. The last five seismic design codes (1968, 1975, 1998, 2007 and 2018) were taken into account within the scope of this study. The differences in dimension and material grades of structural elements such as columns as beams have been compared in de tail for each code. Three different analysis types have been performed for a 4-story reinforced-concrete model such as eigenvalue, pushover and dynamic time-history via the minimum conditions for these elements in each code. The natural vibration period of the building was obtained with empirical formulas stipulated in different codes for the sample RC building, additionally. The size and the type of the materials used in beams and columns within the last five codes have been changed. We see that the changes in these two important parameters which affect the behavior of buildings during an earthquake, enhance the performance of the building. It has been revealed that changes and renewals in seismic design codes are a necessity and gain. It has been clearly revealed that each amended code increases the stiffness and enhance the seismic capacity of a structure. Each updated seismic design code is aimed to complete the deficiency of the previous one. The results revealed that there are changes to be made to increase the seismic capacity of the structure at the point of reducing earthquake damage.
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In determining the seismic performance of reinforced concrete (RC) structures in na tional and international seismic code, it is desired to use effective section stiffness of the cracked section in RC structural elements during the design phase. Although the effective stiffness of the cracked section is not constant, it depends on parameters such as the dimension of the cross-section, concrete strength and axial force acting on the section. In this study, RC column models with different axial load levels, con crete strength, longitudinal and transverse reinforcement ratios were designed to in vestigate effective stiffness. Analytically investigated parameters were calculated from TBEC (2018), ACI318 (2014), ASCE/SEI41 (2017), Eurocode 2 (2004) and Eu rocode8 (2004, 2005) regulations and moment-curvature relationships. From the numerical analysis results, it is obtained that the axial load level, concrete strength, longitudinal and transverse reinforcement ratios have an influence on the effective stiffness factor of RC column sections. The calculated effective stiffness for RC col umns increases with increasing transverse reinforcement ratio, longitudinal rein forcement ratio and concrete strength. Due to the increase of axial force, effective stiffness values of concrete have increased.
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Strengthening historical buildings and evaluating their performances make great contributions to both the history of the country and the tourism of the country. In this study, performance analysis and evaluations of the historical cinema hall bal-cony, which was built in 1933 by a French company and served to Zonguldak prov-ince for a long time, are presented in detail. This cinema hall was frequently used by local people between 1933 and 1999 and hosted many Yeşilçam movies. Firstly, ex-aminations were performed in the historical cinema hall and the areas (columns, beams and floors) that were damaged in time were identified. According to the ob-tained information, it was determined that there were significant damages in the car-rier system of the building and there were visible cracks and damages in the columns of the cinema hall. It was also observed that explosions occurred in one of the main carrier columns of the balcony. After the core samples taken from the balcony were tested in the laboratory, the currentstatus of the carrier elements and reinforce-ments were determined with the help of an x-ray rebar scanner. After all these pro-cesses, the structure was modeled as three dimensional (3D) using a special com-puter program and performance evaluations were performed regarding the current state of the structure. As a result of the performance evaluation, it was determined that the balcony of the historical cinema hall could not survive anymore and would collapse over time. It was concluded that there were great damages especially on the balcony columns and a reinforcement should be made on a total of 6 columns. Strengthening was made to 4 different main columns and a performance analysis was performed again in strengthened structure. After strengthening, it was understood that the columns of the balcony of the cinema hall could survive for a long time.
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In the recent years natural fiber reinforced composites are increasingly receiving attention from the researchers and engineers due to their mechanical properties comparable to the conventional synthetic fibers and due to their ease of preparation, low cost and density, eco-friendliness and bio-degradability. Natural fibers such as kenaf or flux are being considered as a viable replacement for glass, aramid or carbon. Extensive experimental studies have been carried out to determine the mechanical behavior of different natural fiber types such as the elastic modulus, tensile strength, flexural strength and the Poisson’s ratio. This paper presents a review of the various experimental studies in the field of fiber reinforced composites while summarizing the research outcome about the elastic properties of the major types of natural fiber reinforced composites. Furthermore, the performance of a kenaf reinforced composite plate is demonstrated using finite element analysis and results are compared to a glass fiber reinforced laminated composite plate.
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