Ingeniería Civil y Mecánica

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Subject: search.filters.subject.CURVAS DE FRAGILIDAD

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    Construcción de curvas de fragilidad al colapso del Parqueadero del Mercado Central de Ambato
    (Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica. Maestría en Ingeniería Civil con Mención en Estructuras Metálicas, 2024-10) Morales Criollo, William Mauricio; Ramírez Cabrera, Wladimir José; Universidad Técnica de Ambato. Facultad de Ingeniería Civil y Mecánica
    Ambato is located in a geographical region with a high risk of seismic activity, which represents a danger for its inhabitants; this research focused on the estimation of the probability of damage of the Ambato Central Market parking lot using the time-history analysis method by obtaining collapse fragility curves from the generation of IDA curves, in addition, the structure was subjected to 7 site seismic records, each one with its 2 pairs of records duly scaled and corrected. In this research it was necessary to follow the guidelines of ASCE 41-17, FEMA and NEC 2015. In the model analysis it was visualized: torsional distortion and absence of non-precalibrated connections. The results showed that the analyzed structure reached the immediate occupancy level (IO) and did not reach the life safety level (LS) since the structure collapsed. It was determined that the parking lot is more vulnerable in the Y direction presenting the following damage probabilities: 24.67 percent with no damage to the structure, 38.10 percent at an IO level and 37.23 percent at a Total Collapse in an Occasional seismic event with maximum spectral acceleration of 0. 85 g; for a Rare seismic event the following probabilities were evidenced: 0.78 percent with no damage to the structure, 14.64 percent at an IO level and 84.57 percent for Total Collapse at maximum spectral acceleration of 1.19 g. A total of 271 nonlinear time-history dynamic simulations were performed. The high frequency of earthquakes in Ecuador requires the development of more advanced structural analyses for a more accurate evaluation of the behavior of buildings. This research promotes the application of collapse fragility curves as a more accurate alternative to take preventive measures to reduce human and economic losses.
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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.