Diseño de fundaciones superficiales corridas apoyadas sobre suelos granulares en base a asentamientos sísmicos admisibles
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Fecha
2017
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
En Chile, las normas de diseño sísmico no indican de forma explícita cómo abordar el diseño de fundaciones superficiales. Producto de esto, no se dispone de metodologías estándar para el cálculo de capacidad de soporte, ni tampoco para la estimación de asentamientos por concepto de reducción de la capacidad de carga durante terremotos. Por otro lado, si bien en nuestro país se ha observado un buen comportamiento sísmico histórico de fundaciones, no se tiene conocimiento del nivel de asentamientos que cabría esperar, para un terremoto dado, en una fundación superficial diseñada con los criterios estáticos típicamente utilizados en la práctica.
La presente memoria tiene como finalidad evaluar asentamientos sísmicos de fundaciones superficiales corridas en suelos granulares que se ubican en zonas de subducción y que han sido diseñadas en base a factores de seguridad estáticos. Para ello, se realiza un análisis paramétrico sobre la base de una fundación corrida, sometida a carga vertical centrada en su centro geométrico. Para determinar la capacidad de soporte de la fundación y el coeficiente de aceleración horizontal crítico se utiliza una teoría de desarrollada en el contexto del método de equilibrio límite, mientras que para el cálculo de los asentamientos sísmicos asociados se emplea un modelo recientemente desarrollado para estructuras de tierra a emplazarse en zonas de subducción.
Se analiza la influencia tanto de parámetros de la fundación superficial (empotramiento, ángulo de fricción interna del suelo, factor de seguridad estático) como de parámetros sísmicos (magnitud de momento, aceleración máxima del suelo, coeficiente de aceleración pseudo-estático crítico) en los asentamientos esperados y se entregan recomendaciones generales para la aplicación del análisis llevado a cabo en cálculos de diseño preliminar.
In Chile, the current seismic design standards do not indicate explicitly how to assess the design of shallow foundations. As consequence, there is a lack of standard methodologies to estimate the bearing capacity, and to determine the settlements associated with the bearing capacity reduction during earthquakes. On the other hand, even though an overall good seismic performance of foundations has been observed historically in our country, there is not sufficient knowledge about the settlements, for a given earthquake, that could be expected in a shallow foundation designed with the static criteria commonly used in engineering practice. The main goal of this work is to evaluate seismic settlements of shallow strip foundations on granular soils, located in subduction zones, which have been designed using static safety factors. For this purpose, a parametric analysis is performed over the basis of a shallow strip foundation, subjected to vertical loading in its geometric center. In order to determine the bearing capacity of the foundation and the critical horizontal seismic coefficient, a theory developed in the context of the limit equilibrium method is used; whereas to calculate the associated seismic settlements, a recently developed method for earth structures to be located in subduction zones is utilized. The influence on the expected settlements of both, parameters of the shallow foundation (embedment depth, friction angle of soil, static safety factor) and seismic parameters (moment magnitude, peak ground acceleration, pseudo-static critical acceleration coefficient) is analyzed, and general recommendations for the application of the analysis performed are given for preliminary engineering calculations.
In Chile, the current seismic design standards do not indicate explicitly how to assess the design of shallow foundations. As consequence, there is a lack of standard methodologies to estimate the bearing capacity, and to determine the settlements associated with the bearing capacity reduction during earthquakes. On the other hand, even though an overall good seismic performance of foundations has been observed historically in our country, there is not sufficient knowledge about the settlements, for a given earthquake, that could be expected in a shallow foundation designed with the static criteria commonly used in engineering practice. The main goal of this work is to evaluate seismic settlements of shallow strip foundations on granular soils, located in subduction zones, which have been designed using static safety factors. For this purpose, a parametric analysis is performed over the basis of a shallow strip foundation, subjected to vertical loading in its geometric center. In order to determine the bearing capacity of the foundation and the critical horizontal seismic coefficient, a theory developed in the context of the limit equilibrium method is used; whereas to calculate the associated seismic settlements, a recently developed method for earth structures to be located in subduction zones is utilized. The influence on the expected settlements of both, parameters of the shallow foundation (embedment depth, friction angle of soil, static safety factor) and seismic parameters (moment magnitude, peak ground acceleration, pseudo-static critical acceleration coefficient) is analyzed, and general recommendations for the application of the analysis performed are given for preliminary engineering calculations.
Notas
Tesis (Ingeniero Civil)
Palabras clave
Diseño Antisísmico, Construcción