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Foundation analysis and design
01 Jan 1968-
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
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TL;DR: The effect of slime on the engineering characteristics of large-diameter cast-in-place (CIP) piles is not understood as discussed by the authors. But, the results revealed that the general levels of slime at the bottom of the borehole had an insignificant influence on the structural characteristics of the large diameter CIP pile because the slime is susceptible to being mixed with poured concrete and compressed by the self weight of the pile.
Abstract: Slime forms at the bottom of boreholes under the effect of groundwater. The larger the borehole, the more the slime. The demand for large-diameter cast-in-place (CIP) piles has increased as the number of large structures has increased. Excessive slime management can delay construction. However, the effect of slime on the engineering characteristics of large-diameter CIP piles is not understood. In this study, the strength of slime-concrete mixtures was investigated by varying the volume ratio of slime. Field-scale testing was performed to evaluate the behavior of the large-diameter CIP pile using bidirectional load testing. A numerical analysis was performed to assess the compressibility of the slime under the self-weight of the pile. The results revealed that the general levels of slime at the bottom of the borehole had an insignificant influence on the engineering characteristics of the large-diameter CIP pile because the slime is susceptible to being mixed with poured concrete and compressed by the self-weight of the pile.
TL;DR: In this article , a 3D numerical model using the finite element technique and the commercial software ABAQUS is presented to simulate the case of a group of stone columns installed in soft clay.
Abstract: ABSTRACT Stone columns are widely used around the world as cost-effective soil improvement techniques for highways and embankments. They are also used as drainage to expedite the consolidation period, and accordingly to increase the allowable pressure, reduce settlement, and reduce the liquefaction potential for shallow foundations. Currently the design of these columns is based on the unit cell or homogenised material concepts, which neglect the effect of the interaction of the columns. This paper presents a 3-D numerical model using the finite element technique and the commercial software ‘ABAQUS’ to simulate the case of a group of stone columns installed in soft clay. The model is capable of capturing the interaction between columns and the surrounding soil and of establishing the mode of failure of the system. After validating the model with the available experimental results, it was used to predict the allowable pressure and the failure mechanism of groups of stone columns for given geometry/soil conditions. An improvement factor was introduced ‘IF’, which is defined as the ratio of the capacity of the improved to the unimproved soft clay. The results of this investigation are presented in the form of design charts to assist the engineer to determine the level of improvement needed to achieve a given allowable pressure for the foundation.
TL;DR: In this paper , a metodología utilizada for el análisis de pilotes sometidos a cargas axiales-laterales, with the posibilidad of implementarse in programas como Microsoft Excel or lenguajes de programación de Matlab, was presented.
Abstract: Las investigaciones de pilotes sometidos a cargas axiales y laterales han generado como resultado la creación de softwares especializados en el modelado del comportamiento del pilote para estimar los posibles desplazamientos y efectos en la estructura. Sin embargo, estos softwares tienen un costo elevado que los hace inaccesibles para estudiantes universitarios o jóvenes ingenieros civiles. Considerando esto, el objetivo de la investigación es presentar la metodología utilizada para el análisis de pilotes sometidos a cargas axiales-laterales, con la posibilidad de implementarse en programas como Microsoft Excel o lenguajes de programación de Matlab. La metodología se encuentra conceptualizada en diferentes textos que abordan en profundidad el tema de las cargas laterales en pilotes, por lo que se presentan algunos aspectos relevantes en conjunto con las ecuaciones gobernantes que deben ser aplicadas mediante el método de diferencias finitas. Los resultados generados a partir de la metodología expuesta fueron comparados entre el lenguaje de programación Matlab y el programa Microsoft Excel, y posteriormente con los resultados de una prueba centrífuga publicados en un trabajo de tesis doctoral. Dentro de las diferentes características de cada técnica empleada, se obtuvieron resultados favorables en las curvas obtenidas. Con este artículo se busca generar una fuente de consulta en lo referente al análisis y cálculo de cargas laterales, las cuales juegan un papel importante en el diseño de edificaciones civiles, estructuras costeras y oceánicas.
01 May 2014
TL;DR: In this paper, a simplified numerical strategy of four steps is proposed in order to include the soil-foundation interaction into the calculations of a global structure, with a reduced number of calculations and less complexity.
Abstract: The estimation of the structural response of civil engineering structures as they are subjected to different combination of loadings is currently done by the use of numerical models, and its effectiveness depends on how boundary conditions are included into the mod- el. In the case of constructions seated on clay soils, a numerical difficulty resides in how to model the soil-foundation interaction as well as the non linear material behavior of soil. In this work a practical engineering solution is presented in which a set of some simplified foun- dation elements is integrated into the conventional analysis of a building. A simplified numer- ical strategy of four steps is proposed in order to include the soil-foundation interaction into the calculations of a global structure. Regarding to the soil-foundation interaction, two super- elements called "Isolated Foundation Element (IFE)" and "Continuous Foundation Element (CFE)" are numerically formulated, being able to take into account the non linear material behavior of a stratified soil -in particular, long term deformability -, the influence of the soil region in the vicinity of the embedded foundation and their effects in the whole structural sys- tem. Both formulations include different criteria for evaluating soil stress distribution (Bous- sinesq, Westergard, Fhrohlich) as well as the evaluation of the volumetric deformation for a stratified soil (Zeevaert semi-empirical criteria). In order to evaluate the robustness of the proposed strategy, some foundation cases are analyzed in the finite element codes ANSYS and GeoStudio, as well as using the IFE/CFE elements: the comparison of the numerical results shows a good performance of the proposal, with a reduced number of calculations and less complexity.
Cites methods from "Foundation analysis and design"
...In order to consider the effect of soil settlement in the global response, the model includes different soil stress distribution’s criteria (Boussinesq, Westergaard and Fhrohlich methods [2][4]) as well as the phenomenological model proposed by Zeevaert [1] to evaluate the volumetric deformation for a stratified soil....
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01 Jan 2013
TL;DR: In this paper, the results obtained by analyzing load tests, in relation to design calculations of 10 piles, with the purpose of establishing which of the design methodologies more adequately refl ects the geotechnical conditions of our country.
Abstract: The conventional design methodology in deep foundations is governed by the calculation of mathematical expressions based on theoretical principles of soil mechanics, in order to dimension the elements with an appropriate safety factor against bearing capacity failure or settlements that put the structure at risk. However, the values produced in the mathematical calculations are generally conservatives when they are compared with the measured values of load test, taking into account that this type of testing is not usually performed. This article presents the results obtained by analyzing load tests, in relation to design calculations of 10 piles; with the purpose of establishing which of the design methodologies more adequately refl ects the geotechnical conditions of our country.