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The world of foundation engineering
Published in Rodrigo Salgado, The Engineering of Foundations, Slopes and Retaining Structures, 2022
Foundations may take many different configurations, being most generally classified as shallow (covered in Chapters 8–11) or deep (covered in Chapters 12–15). The most common types of shallow foundations are concrete footings, typically built of reinforced concrete in shallow excavations with plan areas most often in the 1–10 m2 range. Piles are the most common type of deep foundations. These are slender structural elements made of wood, steel, or concrete that, in onshore applications, have diameters ranging from 0.1 m to in excess of one meter and lengths ranging from a few to many tens of meters.1 Foundation engineers are also called upon to safely and economically design and build retaining structures of all kinds. Construction dewatering and excavations are also often part of foundation works. Reinforced concrete design of foundations and retaining structures is often done by a structural engineer; in such cases, the best results are obtained when the structural and foundation engineers work in close cooperation.
Foundations
Published in Alan J. Lutenegger, Soils and Geotechnology in Construction, 2019
In general, there are several common types of shallow foundations currently in use: (1) continuous-strip footings; (2) individual isolated footings (square, rectangular, circular); (3) combined footings; (4) mat foundations; and (5) ring footings. All of these are widely used in geoconstruction and have different applications, but all have similarities. Additionally, for light construction, slab-on-grade foundations, which act as both the foundation and the floor slab, are also frequently used.
Bearing capacity of shallow foundations
Published in Hsai-Yang Fang, John L. Daniels, Introductory Geotechnical Engineering, 2017
Hsai-Yang Fang, John L. Daniels
To ensure satisfactory performance of a shallow foundation, it is necessary to provide adequate safety against shear failure of the foundation soil and to prevent excessive settlement of the foundation. These general requirements and related information are (a) subsurface conditions including soil type, depth of the groundwater table, frost penetration depth, and topographical features; and (b) footing characteristics including footing width, footing depth, footing shape, and footing base condition. There are numerous methods for determination of the bearing capacity of shallow foundations that can be further grouped into four basic approaches as theoretical approach, in situ measurement, correlation with other soil parameters, and building codes. Before discussing these various methods for determining the bearing capacity of ground soil, it is necessary to review the general ground stability analysis methods available.
Effect of sheet pile wall on the load-settlement behaviour of square footing nearby excavation
Published in Geomechanics and Geoengineering, 2023
Hussein Ahmad, Mohammad Hosein Hoseini, Ahmad Mahboubi, Ali Noorzad, Mostafa Zamanian
In reality, deep excavations in the vicinity of old buildings have a great impact on their behaviour. Limited researchers have been interested in the presence of excavation in the vicinity of a surface foundation lying a reinforced soil by conducting laboratory experiments as physical models. However, it has not been studied numerically. Therefore, this investigation is intended to highlight this practice problem by conducting numerical modelling. Researchers have discussed the advantages of shallow foundations (such as strip, square, and rectangular foundations) and their effects on the load-bearing capacity of reinforced soil (Binquet and Lee 1975, Akinmusuru and Akinboladeh 1981, Guido et al. 1986, Khing et al. 1993, Das and Omar 1994, Adams and Collin 1997, Shin et al. 2002, El Sawwaf 2007, Latha and Somwanshi 2009, Castelli and Lentini 2012, Abu-Farsakh et al. 2013, Javdanian 2017, Badakhshan et al. 2017, Ahmad et al. 2020).
Using TDA underneath shallow foundations: simplified design procedure
Published in International Journal of Geotechnical Engineering, 2022
Shallow foundations are the simplest and most common type of foundation. In many instances, they are the most cost-effective choice to support superstructures, because they are relatively inexpensive to construct and do not require specialized construction equipment (Das 2016). Shallow foundations serve to distribute structural loads from the superstructure over larger areas of near-surface soil, so as to lower the magnitude of stresses induced by the applied loads to levels that can be tolerated by the foundation soils (Bowels 2001). When subsurface conditions are appropriate, shallow foundations can be used in various applications ranging from footings for signposts, to footings under buildings, to strip footings supporting retaining walls, to bridge piers and abutments. Isolated footings, which are the most common type of shallow foundation, are used to support single columns and their size is calculated based on the load acting on the supported columns and the allowable bearing capacity of the soil (Das 2016).
Upper bound kinematic approach to seismic bearing capacity of strip foundations resting near rock slopes
Published in European Journal of Environmental and Civil Engineering, 2020
Samir Maghous, Zied Saada, Denis Garnier, Vanessa Fátima Pasa Dutra
Design and evaluation of the bearing capacity of shallow foundations lying upon horizontal soil or rock masses under vertical load is still an important issue in rock and geotechnical engineering, and many investigations have been made to provide fully satisfactory solutions for a long time. Less effort has been, however, dedicated to devising predictive design methods when one deviates from this configuration of reference. This is particularly the case if the shallow foundation is located near an excavation or the edge of a slope, such as strip footings for transmission towers and bridge abutments or lying in mountainous regions, which significantly reduce the ultimate bearing capacity of the foundation. Moreover, many structures in earthquake zone involve the construction of foundations on sloping rocks. In such situations, the coupling between the slope stability and the ultimate bearing capacity analyses reveals an important feature in the design of the supported structure. As regards the assessment of the ultimate bearing capacity reduction due to the proximity of a slope edge, several experimental studies carried out at either reduced or real scales, and calculation methods formulated within plane strain or three-dimensional settings, have been devoted to addressing this issue. A detailed review of these studies may be found, for instance, in references (de Buhan & Garnier, 1998; Leshchinsky & Xie, 2017). Most of these works are performed assuming that the geomaterial strength capacities are described by the linear Mohr-Coulomb failure criterion. It was however experimentally proved that rocks generally exhibit nonlinear strength envelopes (Agar et al., 1987; Goodman, 1988; Hoek, 1983; Hoek et al., 2002; Hoek & Brown, 1980, 1997; Jiang et al., 2003; Marinos & Hoek, 2001). The nonlinearity of the failure criterion observed for a large interval of normal stresses has been also corroborated by several upscaling approaches (de Buhan et al., 2002; de Buhan & Maghous, 1997; Maghous et al., 1998, 2008). Referring to the class of nonlinear strength criteria specifically formulated to account for a decrease in friction angle with the increase in confining normal stress, the Hoek-Brown strength criterion and related modified versions appear well-suitable for modeling at macroscopic scale the strength properties of isotropic rocks.