Structural and Infrastructural Safety
KOLAWOLE ABEJIDE; Jubril Kaura Mohammed; Ibrahim Aliyu; Adamu Lawan; Olugbenga Samuel ABEJIDE
Abstract
This study presents structural damage identification using power spectral density (PSD) approach for reinforced concrete bridge decks at varied deck thicknesses. The effect of vibrations due to the applied load on the bridge decks were examined using finite element analysis (FEA) as coded in ABAQUS CAE ...
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This study presents structural damage identification using power spectral density (PSD) approach for reinforced concrete bridge decks at varied deck thicknesses. The effect of vibrations due to the applied load on the bridge decks were examined using finite element analysis (FEA) as coded in ABAQUS CAE software. AASHTO LRFD design equations were used to evaluate the loadings responsible for the intrinsic stresses generated in the bridge decks during their design period. An increasing decline in the internally resistive stresses was observed as the deck thickness was increased, which is consistent with experimental data. It was observed that the deck thickness has a great effect on the response to vibrations due to the applied loads. The 200mm deck thickness had more response to the effect of the applied load and vibration than the 225mm and 250mm deck thicknesses respectively. This is simply because the increase in thickness of the deck serves as a damper, hence reduces the frequency of excitation in the deck. Most bridge decks in reinforced concrete are generally of 200mm thick, hence, the cracking and frequency of maintenance. Thus, it is economically justifiable to justify increase in deck thickness to at least 225mm or 250mm in order to improve on durability, reduce deck cracks, maintainability, durability, and justify investment of funds. This will also reduce the effect of spalling of concrete and improve bond strength between concrete and the reinforcements.
Structural and Infrastructural Safety
Vahed Ghiasi; Fahime Sohrabi
Abstract
Excess soil stress may lead to an additional settlement or shear failure of the soil, which in both cases, causes damage to the structure. Therefore, geotechnical and structural engineers who design the foundation must evaluate the bearing capacity of the soil. This study discusses the optimization of ...
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Excess soil stress may lead to an additional settlement or shear failure of the soil, which in both cases, causes damage to the structure. Therefore, geotechnical and structural engineers who design the foundation must evaluate the bearing capacity of the soil. This study discusses the optimization of the bearing capacity of shallow foundations and a compares deterministic and probabilistic methods. In this study, the bearing capacity of shallow foundations were defined using the Monte Carlo method, finally suggests constructive solutions to improve shallow foundations’ performance.
Structural and Infrastructural Safety
Vahed Ghiasi; Mehran Azami
Abstract
In this review article, we examine the behavior of earthen dams under earthquake movements. Earthen dams perform satisfactorily when exposed to strong earthquakes. Their performance is usually related to the nature of the soil used for the structure. Most well-constructed earthen dams can significantly ...
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In this review article, we examine the behavior of earthen dams under earthquake movements. Earthen dams perform satisfactorily when exposed to strong earthquakes. Their performance is usually related to the nature of the soil used for the structure. Most well-constructed earthen dams can significantly vibrate the earthquake without damaging effects. Dams made of compacted clay materials on clay foundations or bedrock withstood strong ground movement. Compared to older embankments built on sandy materials or of sand or silt with inefficient density and tailings dams, all of them showed almost some instances of failure, which was initially due to the liquefaction capability of these materials. They are considered a type of hydraulic structure in this period, and tailings dams are the most dangerous types of earth dams. The more accurate and durable equipment and tools are used during the construction and operation of the dam, the minor deformation is created in the dam, and the more controllable it becomes. Utilizing up-to-date knowledge and benefiting from the construction and maintenance experiences of the dam can help the optimal management of the dam during construction and operation. The main finding from this study is earth dams have better flexibility to accept the dynamic load due to earthquake force than concrete dams.
Structural and Infrastructural Safety
Sachin Popat Patil; Jagadish G Kori
Abstract
This study evaluates the performance of an RC frame structure using nonlinear static and nonlinear dynamic analysis procedures. To achieve this objective, five-moment resisting frames with 4,8,12,16,20 storied buildings were analyzed and designed following the guidelines of the seismic codes was subjected ...
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This study evaluates the performance of an RC frame structure using nonlinear static and nonlinear dynamic analysis procedures. To achieve this objective, five-moment resisting frames with 4,8,12,16,20 storied buildings were analyzed and designed following the guidelines of the seismic codes was subjected to single, double, and triple earthquake events, that is, repeated earthquakes. The assessment of the structure in terms of the failure of members and the performance of the structure in terms of displacement and ductility was measured for different earthquake events, which was then converted into a multiplying factor. These seismic performance factors were used to increase the strength and stiffness of the structures at various locations. These factors were used for the design of an earthquake force-resisting system in a new building. In this study, the performance of a building subjected to a maximum considered earthquake (MCE) and for a repeated earthquake is checked and applied to the revised design procedure of the structure. By considering different performance points of the structure when subjected to repeated earthquakes, a new design philosophy was introduced. The building was designed using this new philosophy, and the structural stability of the structure was verified by applying repeated earthquakes.
Structural and Infrastructural Safety
Sachin Popat Patil; Jagadish G Kori
Abstract
According to current practices in earthquake engineering, and as per guidelines of codes the multistoried structures are analyzed and designed only for a single, rare design earthquake. In reality, most of the locations are affected by multiple earthquakes within short time intervals, also the repeated ...
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According to current practices in earthquake engineering, and as per guidelines of codes the multistoried structures are analyzed and designed only for a single, rare design earthquake. In reality, most of the locations are affected by multiple earthquakes within short time intervals, also the repeated earthquake effect is ignored. The repeated earthquake affects the strength and stiffness degradation of the structure. In this paper4-, 8-, 12-, 16-storey structures are investigated under repeated earthquakes. The Time history analysis is performed with single, double, and triple earthquake events for calculating drift, displacement, and ductility. The result shows that the drift, displacement, and ductility demand increase with compared to a single earthquake. This research focuses on the study of the effect of a single and repeated earthquake on the multistoried structure and damage identification can be found using deformation in building frame or in frame element with the formation of plastic hinges. The default hinge properties are assigned to elements of structure and the study is carried out to find the location, formation of plastic hinges, and plastic hinge rotation due to repeated earthquake and this study is used to strengthening the element strength. This paper studies the interstory drift ratio and displacement under aftershocks of an earthquake and remedial measures are suggested to strengthen the structure capacity.
