Unidad de Posgrado Civil y Mecánica

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    Diseño por capacidad partiendo de un análisis comparativo entre el método modal espectral y el método tiempo historia con el uso de acelerogramas sintéticos y la Norma Ecuatoriana de la Construcción 2015; de un edificio de 9 pisos en estructura metálica
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Ingeniería Civil con Mención en Estructuras Metálicas, 2022-09) Cevallos Cabrera, Jorge Washington; Medina Robalino, Wilson Santiago
    National and international regulations are being updated based on the lessons learned from seismic events; having buildings designed in some cases with regulations that were not very demanding in the dynamic part and in other cases built without any technical procedure; it is necessary to improve the analysis of the behavior of the structure subjected to lateral forces produced by earthquakes in a controlled manner, leading to a theoretical collapse of the structure. This variation is achieved by progressively increasing the amplitudes of the accelerograms used as dynamic excitation. In this work, this numerical procedure for the evaluation of the seismic behavior of structures is applied in order to evaluate the values of the behavior factor postulated in the Ecuadorian Standard for the seismic-resistant design of special steel moment-resisting frames. However, due to the non-linear behavior of the soil, the solution is limited to a set of activities inherent to the correct structural modeling and use of properly filtered seismic records. Regarding the generation of synthetic accelerograms, they must be adjusted to an objective spectrum involving the non-linear behavior of the soil; although it is true that spectral adjustments in the time domain, due to the existence of public domain software, are relatively simple procedures to execute, it is necessary to have a wide knowledge in this type of procedure. In the process of verifying the compatibility of the responses of the vibration period of the structure by placing it as a percentage of the distance and moving the center of masses according to the Ecuadorian standard, it was evidenced that the period of the structures does not affect, due to the fact that the static eccentricity between the center of masses and the center of stiffness can increase more or less; being noticeable the more irregular the structure. By scaling the accelerograms with the response spectrum provided by the NEC; to make synthetic accelerograms, the pseudo-spectral acceleration tends to be similar to the acceleration of the target spectrum, so it could be more productive to work with accelerograms of low magnitude earthquakes, being indispensable to take into consideration the parameters of focal depth, type of fault, soil conditions, etc. For capacity analysis, it is possible to choose only the structural elements that could have some suspicion of failure, concentrating all our effort in solving these elements; it should be clear that the design by capacity does not provide design data, the results obtained serve to analyze the possible complications that could occur in the structure during a seismic movement; it is important to emphasize that they are not totally real data, taking into account that an earthquake has many variables that are not taken into account during the nonlinear analysis.
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    Evaluación de vulnerabilidad sísmica de edificaciones metálicas, hormigón y/o mixtas en la parroquia San Bartolomé de Pinllo, Ambato, Ecuador: propuesta de reforzamiento estructural del edificio de San Bartolomé
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Ingeniería Civil con Mención en Estructuras Metálicas, 2023-03) Zúñiga Zamora, Libio Vladimir; Núñez Aldas, Galo Wilfrido
    The current degree project includes two parts, the first one deals with the study of the seismic vulnerability of existing buildings by using three methodologies, two international and one national, which will be carried out using the qualitative method of rapid visual inspection of houses, using the forms by the Federal Emergency Management Agency (FEMA P - 154) standard, the Building Indexes for Seismic Risk Management of the Venezuelan Foundation for Seismological Research (FUNVISIS) and the Practical Guide for Seismic Evaluation and Rehabilitation of Structures, of the Ecuadorian Construction Standard (NEC 2015), each methodology will assign values and vulnerability indexes, and seismic prioritization to all buildings evaluated. The project will be carried out in a sample of buildings in the parish of San Bartolomé de Pinllo in the canton of Ambato, province of Tungurahua, to obtain vulnerability levels of the sector and assess the damage that may occur in buildings in an earthquake, hence the importance of proposing the research of modern systems of structural reinforcement. The buildings of the parish have vulnerabilities that are between medium-low and medium-high, which demonstrates the importance of applying these methods of rapid evaluation so that local governments can propose mitigation plans for seismic disasters. The second part of the research proposes the study of the steel building of the Decentralized Autonomous Government of San Bartolomé de Pinllo, with a special occupancy category, which is required to determine its structural behavior with the increase of two additional floors to the building, through static, linear dynamic and nonlinear analysis, respectively. To do so, three structural models of the 6-story building were applied. In the first one, linear static and dynamic analysis was developed, in which the effects of the loads and the equilibrium of the internal forces of the structure were determined, to obtain displacements and floor drifts according to the Ecuadorian Construction Standard (NEC 15); In the second model, it was possible to determine the behavior of the structural elements with the sections considered, which make up the building, through plastic ball joints, using a non-linear static analysis (PUSHOVER), to obtain an indicator of the performance of the existing structure. In the third structural model, viscous fluid-type energy dissipators with single diagonal-type configurations were implemented. In addition, three pairs of synthetic accelerogram records were considered, each with its two horizontal components N-S and E-W, parameters necessary to analyze the structure through a nonlinear dynamic analysis (Time-History), to obtain the behavior of the structure with more real data and control its effects resulting from the increase of the two required floors, with which results of the influence of the dissipators on the structure, floor drifts, displacements and performance levels were obtained. The structural elements and the proposed reinforcement system were designed based on the American Institute of Steel Structures Code (AISC 360-10), the American Society of Civil Engineers (ASCE/SEI 41-17), and the Ecuadorian Construction Standard (NEC-15). Finally, the referential cost of the proposed reinforcement system was determined.