Load Transfer, Lateral Loads, and Group Action of Deep Foundations

2009 ◽  
pp. 5-5-10 ◽  
Author(s):  
A. S. Vesić
2002 ◽  
Vol 2 (2) ◽  
pp. 273-276
Author(s):  
V.R. Ouhadi . ◽  
A. Ghalandarzadeh .

2005 ◽  
Author(s):  
◽  
Eng-Chew Ang

The objective of the work is to use numerical analyses to evaluate the limit soil pressure on piles, to evaluate the load transfer mechanism, and to evaluate alternative means for estimating mobilized and limit loads on piles in piled-slope problems. It is found that limit forces predicted using 2-D, plane strain and 3-D analyses differ substantially. The computed limit force on piles in piled-slopes is sensitive to the interface roughness, pile spacing, modeling techniques, and constitutive model. For the 3-D model, which includes both the sliding and anchorage zones, the limit soil pressure calculated for the "flow" failure mode is approximately equal to that predicted by the Broms (1964) method. It is concluded that 2-D analyses of a horizontal slice is not suitable for evaluation of mobilized or limit lateral loads on piles. The 3-D mode analysis is a better method for modeling the actual piled-slope problems.


2021 ◽  
Vol 337 ◽  
pp. 03008
Author(s):  
Rafael Baltodano-Goulding ◽  
Laura Brenes-Garcia

The structural design of deep foundations depends on both the applied loads and the soil that will support them. However, during an earthquake this process reverses, and the seismic stresses are transmitted towards the structure through the soil. Proper design of deep foundations must account for the lateral loads imposed on the foundations by the dynamic loading. In order to assess the influence of soil saturation in the transmission of a dynamic load to a foundation, a dynamic lateral load pile design was performed using Reese’s p-y curve method. A series of suction-controlled dynamic triaxial tests were performed to obtain the Modulus of subgrade reaction at different matric suctions and seismic coefficients were back-calculated to perform structural designs. In general terms, it was observed that contemplating a saturated soil in the dynamic lateral load pile design does not represent the critical load case for seismic analysis.


Author(s):  
Jorge R. Parra ◽  
J. Erik Loehr ◽  
David J. Hagemeyer ◽  
John J. Bowders

The performance of earth slopes reinforced with arrays of slender reinforcing members is currently being investigated. The reinforcing members used are fabricated from recycled plastics and other waste materials to form sections 90 mm (3.5 in.) × 90 mm (3.5 in.) × 2.4 m (8 ft) long. A design methodology was adopted to estimate the limit resistance provided by each member, which is then incorporated into conventional limit equilibrium slope stability analyses to calculate the improvement in the factor of safety under various reinforcement scenarios. Four field test sites were stabilized using recycled plastic reinforcement to demonstrate the effectiveness of the stabilization scheme and to evaluate the load transfer mechanisms between the soil and the reinforcement. One additional site was stabilized with similarly sized steel pipe members for comparison with the recycled plastic members. The stabilized slopes are performing well, whereas several control sections have experienced failures. The performance of each site is being monitored with field instrumentation to monitor lateral movements, pore pressures, strains within the reinforcing members, and the lateral loads applied to the members. Observations to date indicate that the slopes are performing well and that the reinforcing members have significant remaining capacity to maintain the stability of the slopes.


2014 ◽  
Vol 587-589 ◽  
pp. 1047-1057 ◽  
Author(s):  
How Bing Sii ◽  
Gary W. Chai ◽  
Rudi Van Staden ◽  
Hong Guan

The load transfer mechanism between the dowel and the concrete is a complex phenomenon. This mechanism depends mainly on a parameter known as the modulus of dowel support (K), the value of which can be determined by load testing. A high modulus of dowel support value indicates a good contact between the concrete and the steel dowel. There is a lack of sound approach to identify with any degree of accuracy the modulus of dowel support (k), which makes it difficult to rely on the analytically developed formulas that are sensitive to its value. The obtained numerical results were validated with classical analytical solutions of shear and moment along the dowel. The group action of the dowel bar system was examined and useful relationships have been developed for estimation of the relative load shared by individual dowel bars. These useful relationships have been used to developed prediction Model to predict the shear force in dowel group action of dowel bar system and deflection at the loading nodal point. The prediction Model results for shear force in dowel group action of dowel bar system and deflection at the loading nodal point were relatively close to the F.E. Model results, with the different range between 2.2% to 7%.


2021 ◽  
Vol 1 (25) ◽  
Author(s):  
Abbas Firouzi Karamjavan ◽  
Hojjat Hashempour

In many projects, piles are designed and installed as the ultimate solution in foundation construction, load transition to the resistant subsurface layers, providing lateral resistance, and overcoming the poor performance of surface soils. Pile design should be done with respect to structural consideration, the load-carrying capacity of the surface and surrounding soil, settlement, and constructional, technical and environmental problems. Pile group is a particular type of deep foundations which is mostly and widely utilized in coastal and offshore structures, and sustains vertical and lateral loads. Noting the lateral load exerted on the structure, the effect of loading on the behavior of pile should be analyzed using an appropriate method. In this article, a 4x4 pile group with piles of 100 cm diameter and 10, 15-m in length with center-to-center spacing of 3 times the diameter are modeled using the Plaxis 3D Foundation, which uses the finite element method, and the Mohr-Coulomb model, and the behavior of the piles driven in sand and subjected to loading is studied. Taking the results, the mechanism of the pile group behavior under vertical, lateral, adjacent structures loads and bending moment is calculated, and displacement in the x-direction, y-direction, and along the length, bending moment, and bearing capacity along the length of the pile have been obtained for each pile.


2012 ◽  
Vol 446-449 ◽  
pp. 2663-2666 ◽  
Author(s):  
Hui He ◽  
Yan Bing Liu

Based on the predecessors’ achievements and combined with the engineering project of Jinquan temple landslide located in Hanzhong city of Shanxi province, this paper takes international general geotechnical engineering professional analysis software—FLAC3D to do the numerical simulation. The deformation characteristics and mechanical properties of micropiles in lateral loads are researched. Working performance and load transfer rule of micropiles are analyzed. It is useful for the design of micropiles in 3 rows. It also has positive significance on the construction and design of micropiles reinforcing shallow landslide.


2015 ◽  
Vol 52 (8) ◽  
pp. 1005-1022
Author(s):  
Wilson Cartaxo Soares ◽  
Roberto Quental Coutinho ◽  
Renato Pinto da Cunha

Geotechnical projects typically achieve load transfer to the ground using shallow or deep foundations. The conventional design approach does not provide for the combination of these two types of foundation. The piled raft philosophy allows the association of the soil elements, raft, and piles to obtain technical and economic advantages over conventional design. The city of João Pessoa, in northeastern Brazil, has developed foundation practices with hollow auger piles in piled raft design. The coastal area of the city has topsoil layers with favorable conditions for using such a technique. This paper addresses the results of a research project with instrumented load tests on foundation systems of hollow auger piles and a piled raft. The analysis is based on the load–settlement curve through extrapolation criteria. The Poulos–Davis–Randolph (PDR) method is applied according to a trilinear and hyperbolic approach to simulate the load–settlement curve of piled rafts. The results indicate that the raft absorbs most of the load, and the raft–soil contact significantly increases the load capacity of the foundation. The PDR hyperbolic method could apply to practical use in the foundations of the region, as it allows a more detailed assessment of the behavior of the foundation and can forecast the behavior of the (locally nontraditional) piled raft foundation system.


2017 ◽  
Vol 1 (16) ◽  
Author(s):  
Abbas Firouzi Karamjavan

Pile group is a particular type of deep foundations which is designed and installed as the ultimatesolution to foundation construction, load transition to the resistant subsurface layers, providing lateralresistance, and overcoming the poor performance of surface soils. Pile design should be done withrespect to structural consideration, the load-carrying capacity of the surface and surrounding soil,settlement, and constructional, technical and environmental problems. Piles are mostly and widelyutilized in coastal and offshore structures, and sustain vertical and lateral loads. Considering theimposed loads on structure, the effect of these loads on the pile behavior should be analyzed with anappropriate method. In this study, a 4x4 pile group with piles of 100-cm diameter and center-to-centerspacing of 2, 3, 4 times the diameter is modeled using the Plaxis 3D foundation program, which usesthe finite element method, and the Mohr-Coulomb model, and the behavior of piles subjected toloading, driven in sand, are investigated. Taking the achieved results, the mechanism of the pile groupbehavior under composite loads, adjacent structure loads, and bending moment are calculated, anddisplacement in the x-direction, y-direction and along the length, the bending moment and the axialforce for each pile within a distance of 2, 3, 4 times the diameter are attained.


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