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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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01 Jan 1998
TL;DR: In this paper, the authors evaluated damaged house foundations in Denton, Texas within the context of local geology and found that expansive soils pose a significant hazard to foundations and that the magnitude of this hazard is controlled by underlying rock formations.
Abstract: Damaged house foundations in Denton, Texas were evaluated within the context of local geology. Addresses of 78 damaged structures were compiled from local foundation repair companies. The Cretaceous-age Grayson and Woodbine formations outcrop in the study area. Marl and montmorillonitic clay are predominant constituents of the Grayson formation. The Woodbine formation consists of sand and sandstone interbedded with clay. Textural and compositional differences in these parent materials have lead to significantly higher plasticity indices for Grayson residual soils. The distribution of damaged founda- tions was superimposed on a geologic map to determine the number and spatial density of damages in each formation. A 324 percent higher damage density was calculated for the Grayson formation. Results of this study suggest that (1) expansive soils pose a significant hazard to foundations in Denton, and (2) the magnitude of this hazard is controlled in part by underlying rock formations.
01 Jan 2013
TL;DR: In this article, the effect of ring footings on the bearing capacity of ring foundations has been investigated by means of centrifuge rnodelling, the method of characteristics and the finite element technique.
Abstract: The ring footings are suitable and economical for symmetrical structures such as silos, cooling towers, smoke-stacks, transmission towers, radar stations, TV antennae, chimneys, bridge piers, underground stops, water towers, mine and liquid storage tanks. When compared with the other geometrical shapes of the footings, such as (strip, rectangular, square and circular footings). The ring footings enable decreasing the amount of material used and cost of construction. Ring foundations are often adopted for large and tall structures to resist lateral loads and to increase the stability against overturning. In the design of ring foundations, very cmde simplifications have to be made. Therefore, developing a rational and practical procedure for estimating the bearing capacity of ring foundations is of great importance The effects of footing size, ring radii ratio and load eccentricity have been investigated by means of centrifuge rnodelling, the method of characteristics and the finite element technique.This study presents a series analysis of ring foundation. For analysis ten different model were used. The first of the model footings were circular; the others were ring footings. The diameters of the inner boundaries of the ring foundations for the analysis were 15.75 external dia 14.50m internal dia. The experimental studies indicate that the bearing capacity of the ring footings is depend directly on the ratio of the inside to outside radii, i.e. radius ratio. The Finite Element Method (FEM) Its practical application often known as finite element analysis] is a numerical technique for finding approximate solution to partial differential equation (PDE) and their systems as well as integral equation. In simple terms FEM is method for dividing up a very complicated problem in to small elements that can be solved in relation to each other. The finite-element method (FEM) for a ring foundation is somewhat similar to the beam on-elastic-foundation method. SAP2000 is a general purpose finite element program which performs the static or dynamic, linear or nonlinear analysis of structural systems. It is also a powerful design tool to design structures following AASHTO specifications, ACI and AISC building codes. These features and many more make SAP2000 the state-of-the-art in structural analysis program. The SAP2000 graphic user interface (GUI) is used to model, analyze, design, and display the structure geometry, properties and analysis results.
01 Dec 2013
TL;DR: In this paper, over 100 centrifuge tests were conducted to assess Load and Resistance Factor Design (LRFD) resistance factors for external stability of Mechanically Stabilized Earth (MSE) walls founded on granular soils.
Abstract: Over 100 centrifuge tests were conducted to assess Load and Resistance Factor Design (LRFD) resistance factors for external stability of Mechanically Stabilized Earth (MSE) walls founded on granular soils. In the case of sliding stability, the tests suggest the LRFD Φ values vary from 0.74 to 0.94 and 0.63 to 0.68 using Rankine and Coulomb methods for lateral resultant force, respectively. These values covered wall heights of 8 to 14 ft with variable backfill having μφ=32° and CVφ= 11.7%. The study also revealed that the load factor for horizontal earth pressure agreed very well with current practice (AASHTO, 2012), i.e. 1.5. In the case of bearing stability, the tests support Φ= 0.47 and 0.45 (β= 3.09) for foundation soils with μφ= 26°-30° and 31°-33°, respectively, and Φ= 0.65 and 0.68 (β= 2.32); current practice uses Φ= 0.65. The tests also suggest the use of load inclination factors in estimating bearing capacity. The combination of axial and lateral force, i.e., inclined resultant reduces the depth and length of the bearing failure surface, which is reflected in a reduced capacity. From over 200 measurements, the load factor for vertical earth pressure was determined to be 1.87, which is larger than current practice, 1.35 (AASHTO, 2012), but agrees well with values reported by others for internal stability. In the case of bearing stability of MSE walls near slopes, it was found that current prediction methods (Bowles, Vesic, etc.) are too conservative. Moreover, based on observed failures of MSE walls near embankments, slope stability instead of bearing controls their design
Cites background or methods from "Foundation analysis and design"
...68 5-1 Footing (a) on slope and (b) near slope (Bowles, 1997) ....
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...Figure 5-15 Failure wedge and forces acting on gravity retaining wall for passive earth pressure (Bowles, 1997)...
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...The predicted capacity based on Bowles method used Hansen’s recommended Nγ in Equation 5-5 (as suggested by Bowles, 1997) and for Hansen’s load inclination factor, iγ (Eq....
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...…5-13 Vcalculated versus Vmeasured for all MSE wall near embankment tests ...................................93 5-14 Shallow footing with concentric load and near an embankment (Bowles, 1997) .............94 5-15 Failure wedge and forces acting on gravity retaining wall…...
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...Bowles (1997) suggested calculating a modified N’γ using Equation 5-2 and estimating the qu for footing near an embankment using Equation 5-1....
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