En la presente investigación se evaluó la eficiencia de las pilas de sacrificio en la reducción de la socavación local de pilares cilíndricos y rectangulares de puentes de ríos. Para ello, se realizaron modelaciones numéricas hidrodinámicas, en el software Iber, y se aplicaron las ecuaciones de la Universidad Estatal de Colorado (CSU) y de Froechlich. En esta investigación, se emplearon los resultados del ensayo físico del pilar cilíndrico aislado de 30mm de diámetro, ensayado en el artículo científico desarrollado por Vahdati et al. (2020). Asimismo, se emplearon los resultados del pilar rectangular de nariz semicircular de 30mm de ancho y 150mm de largo, ensayado en el artículo científico desarrollado por Vijayasree, Eldho, Mazumder y Ahmad (2019). Estos ensayos físicos fueron calibrados para, posteriormente, adicionar las pilas de sacrificio, en diferentes configuraciones, y analizar su eficiencia en la reducción de la socavación local. Las configuraciones propuestas para las pilas son: triangular 30°, triangular 180°, en tandem y en tridem. Para el pilar cilíndrico aislado y para el pilar rectangular de nariz semicircular se obtuvieron porcentajes de reducción de la socavación local de hasta 45.32% y 60.75%, respectivamente. De acuerdo a los resultados, las configuraciones en tridem y triangulares de 180° fueron las más eficientes. Además, se realizó un análisis dimensional para conocer la influencia de las variables que intervienen en el fenómeno de socavación local. A partir de los resultados, se observó que el número de Froude (Fr) es el numero adimensional más influyente. / In this research, the efficiency of sacrificial piles in reducing local scour of cylindrical and rectangular piers of river bridges was evaluated through hydrodynamic numerical modeling (in the Iber software) and the application of the equations of Froechlich and Colorado State University (CSU). The results of the physical test of the 30 mm diameter single cylindrical pier, tested by Vahdati et al. (2020), and the results of the physical test of the rectangular pier with semi-circular nose of 30 mm wide and 150 mm long, tested by Vijayasree, Eldho, Mazumder and Ahmad (2019), were used. These physical tests were calibrated to add the sacrificial piles in different configurations and analyze their efficiency in reducing local scour. The proposed configurations for the piles were: triangular 30°, triangular 180°, tandem and tridem. The maximum percentages of reduction of local scour obtained were 45.32% and 60.75% for the single cylindrical pier and the rectangular semi-circular nose pier, respectively. According to the results, tridem and triangular 180° configurations were the most efficient. Likewise, a dimensional analysis was carried out to determine the influence of the variables involved in the phenomenon of local scour. From the results, the Froude number (Fr) was the most influential dimensionless number. / Tesis

Scour is a process of removing soils around foundations by currents and waves. For the pile-supported marine structures such as the monopile-supported offshore wind turbines (OWTs) and the pile-supported bridges, scour can decrease the pile capacities and alter the dynamic responses of the structures. At present, there is not a widely accepted method to estimate pile axial or lateral capacity under scoured conditions. For example, different recommendations are used among the existing design standards for estimation of the vertical effective stress and the resulting capacities for single piles under different scour conditions. None of the existing standards or design practice has even considered the scour effects on the behavior of pile groups. Furthermore, the investigation into the responses of piles under multiple hazards of scour and earthquakes is rarely reported. To address the foregoing limitations, this study first introduces an analytical solution to determining the vertical effective stress of soils around single isolated piles under scoured conditions and uses it to examine the limitations of the existing standards in estimation of pile tensile capacity (Chapter 1). The effect of soil-pile interface friction is highlighted. Next, the study proposes new approaches to investigating the combined effects of scour and earthquakes on the lateral responses of the monopile-supported OWTs in sand (Chapter 2) and soft clay (Chapter 3). Lastly, simple and practical methods are developed based on the p-y curve framework for analyzing the lateral responses of pile groups in sand (Chapter 4) and soft clay (Chapter 5) subjected to static lateral loading. The proposed methods in this study were encoded into a series of open-source computer scripts for engineering practice. They were verified with the 3D continuum finite element (FE) analyses. Using the proposed methods, standard methods, and 3D FE method, parametric analyses were conducted to investigate the scour effects on the lateral behavior of the monopile-supported OWTs under crustal earthquakes and that of the pile groups under static loading. The factors considered in the parametric study included effects of scour-hole dimensions, soil stress history, soil density, soil-pile interface behavior, soil liquefaction potential, pile group configurations, etc. Through the parametric analyses, the standard methods were critically assessed by comparing the results to those calculated by the proposed methods and 3D FE methods, and some design-related issues were also discussed. / Graduate

La socavación en las bases de los puentes es una de las principales causas de fallas de estas infraestructuras en el mundo, lo que conlleva a elevados gastos en reparación, aislamiento de poblaciones y pérdidas de vidas humanas. El presente trabajo de investigación tiene como principal objetivo calcular, analizar y comparar la socavación total que se produce en los pilares y estribos del puente Huallaga mediante un modelo unidimensional y un modelo bidimensional. Para lograr este objetivo se recopilaron las diferentes metodologías de cálculo de socavación y se escogieron las óptimas para el presente estudio. Luego, se identificaron los parámetros que tienen mayor influencia en la simulación del proceso de socavación. Después, se calculó la socavación total del puente Huallaga con el modelo 1D (HEC-RAS) y 2D (IBER). Finalmente, se realizó un análisis comparativo entre los resultados obtenidos en ambos programas. Adicionalmente, se obtuvieron como una de las principales conclusiones que los valores calculados de socavación obtenido a partir de los datos del modelo 2D son menores en comparación a los valores calculados de socavación obtenidos a partir de los datos del modelo 1D, haciendo al segundo modelo hasta un 49.8% más representativo para los cálculos de socavación. / The scour of the bases of the bridges is one of the main causes of failure of these infrastructures in the world, which leads to repair costs, isolation of populations and human losses. The main objective of this research work is to calculate, analyze and compare the total scour that occurs in the pillars and abutments of the Huallaga bridge using a one-dimensional model and a two-dimensional model. To achieve this objective, the different scouring calculation methodologies were compiled, and the optimal ones were chosen for the present study. Then, identify the parameters that have the greatest influence on the simulation of the scour process. Then, he calculated the total scour of the Huallaga bridge with model 1D (HEC-RAS) and 2D (IBER). Finally, a comparative analysis was performed between the results obtained in both programs. Furthermore, it was obtained that the calculated values of scour obtained from the data of the 2D model are lower compared to the calculated values of scour obtained from the data of the 1D model, making the second model up to 49.8 more representative for scour calculations. / Tesis

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