Modelling the applied vertical stress and settlement relationship of shallow foundations in saturated and unsaturated sands

2011 ◽  
Vol 48 (3) ◽  
pp. 425-438 ◽  
Author(s):  
Won Taek Oh ◽  
Sai K. Vanapalli
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Characteristic Curve ◽  
Friction Angle ◽  
Vertical Stress ◽  
Shallow Foundations ◽  
Surface Settlement ◽  
Soil Parameters ◽  
Finite Element Analyses ◽  
Unsaturated Sands

The bearing capacity and settlement of foundations are determined experimentally or modelled numerically based on conventional soil mechanics for saturated soils. In both methods, bearing capacity and settlement are estimated based on the applied vertical stress versus surface settlement relationship. These methods are also conventionally used for soils that are in an unsaturated condition, ignoring the contribution of matric suction. In this study, a methodology is proposed to estimate the bearing capacity and settlement of shallow foundations in unsaturated sands by predicting the applied vertical stress versus surface settlement relationship. The proposed method requires soil parameters obtained under only saturated conditions (i.e., effective cohesion, effective internal friction angle, and modulus of subgrade reaction from model footing test) along with the soil-water characteristic curve (SWCC). In addition, finite element analyses are undertaken to simulate the applied vertical stress versus surface settlement relationship for unsaturated sands. The proposed method and finite element analyses are performed using an elastic – perfectly plastic model. The predicted bearing capacities and settlements from the proposed method and finite element analyses are compared with published model footing test results. There is good agreement between measured and predicted results.

scholarly journals Bearing Capacity of Circular Footing on Sand Deposit

2015 ◽  
Vol 773-774 ◽  
pp. 1518-1523 ◽  
Author(s):  
Aminaton Marto ◽  
Mohsen Oghabi ◽  
Nor Zurairahetty Mohd Yunus
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Experimental Test ◽  
Static Load ◽  
Sandy Soils ◽  
Soil Parameters ◽  
Test Results ◽  
Finite Element Software ◽  
Sand Deposit ◽  
Circular Footing

Bearing capacity and settlement are two important parameters in geotechnical engineering. The bearing capacity of circular foundations on sandy soils is important to geotechnical practicing engineers. Design of foundations includes soil parameters and bearing capacity of foundation. This paper presents the results of laboratory experimental model tests of circular footings supported on sand deposit under static load. The finite element software Abaqus is used to compare the results. The effects of the relative density of the sand (30%, 50%, and 70%) and the diameter of circular footing (75 mm and 100 mm) are investigated. It can be concluded that the experimental test results fit quite well with the results of numerical method.

scholarly journals Load-carrying capacity of welded K-type joints inside floor truss systems

2019 ◽  
Vol 52 (1) ◽  
pp. 38-52
Author(s):  
Pooya Saremi ◽  
Wei Lu ◽  
Jari Puttonen ◽  
Dan Pada ◽  
Jyrki Kesti
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Carrying Capacity ◽  
Numerical Models ◽  
High Load ◽  
Load Carrying Capacity ◽  
Finite Element Analyses ◽  
Load Bearing Capacity ◽  
Load Carrying ◽  
Joint Behaviour

The load-carrying capacity of a K-type joint inside a floor truss is studied both experimentally and numerically. The joint tested is a scaled-down, isolated joint. The tubular braces, plate chord, and division plate are made of SSAB Domex steel. Comparison of load displacement curves received by finite element analyses with curves obtained from tests confirms that numerical models describe joint behaviour reasonable. The paper demonstrates that joints with high load-bearing capacity can be investigated experimentally by scaling the dimensions of the joint down when testing devices can affect the required capacity of the joint. The results presented can also be used for optimizing failure mechanism of similar joints in practice.

Numerical study of ultimate bearing capacity of rectangular footing on layered sand

2020 ◽  
Vol 1 (101) ◽  
pp. 15-26
Author(s):  
V. Panwar ◽  
R.K. Dutta
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bearing Capacity ◽  
Numerical Study ◽  
Friction Angle ◽  
Ultimate Bearing Capacity ◽  
Loose Sand ◽  
Sand Layer ◽  
Element Analysis ◽  
Dense Sand

Purpose: The purpose of this study is to investigate the ultimate bearing capacity of the rectangular footing resting over layered sand using finite element method. Design/methodology/approach: Finite element analysis was used to investigate the dimensionless ultimate bearing capacity of the rectangular footing resting on a limited thickness of upper dense sand layer overlying limitless thickness of lower loose sand layer. The friction angle of the upper dense sand layer was varied from 41° to 46° whereas for the lower loose sand layer it was varied from 31° to 36°. Findings: The results reveal that the dimensionless ultimate bearing capacity was found to increase up to an H/W ratio of about 1.75 beyond which the increase was marginal. The results further reveal that the dimensionless ultimate bearing capacity was the maximum for the upper dense and lower loose sand friction angles of 46° and 36°, while it was the lowest for the upper dense and lower loose sands corresponding to the friction angle of 41° and 31°. For H/W = 0.5 and 2, the dimensionless bearing capacity decreases with the increase in the L/W ratio from 0.5 to 6 beyond which the dimensionless ultimate bearing capacity remains constant for all combinations of parameters. The results were presented in nondimensional manner and compared with the previous studies available in literature. Research limitations/implications: The analysis is performed using a ABAQUS 2017 software. The limitation of this study is that only finite element analysis is performed without conducting any experiments in the laboratory. Further the study is conducted only for the vertical loading. Practical implications: This proposed numerical study can be used to predict the ultimate bearing capacity of the rectangular footing resting on layered sand. Originality/value: The present study gives idea about the ultimate bearing capacity of rectangular footing when placed on layered sand (dense sand over loose sand) as well as the effect of thickness of top dense sand layer on the ultimate bearing capacity. The findings could be used to calculate the ultimate bearing capacity of the rectangular footing on layered sand.

Exact probabilistic solution of two-parameter bearing capacity for shallow foundations

1992 ◽  
Vol 29 (5) ◽  
pp. 867-870 ◽  
Author(s):  
Said M. Easa
Keyword(s):  
Bearing Capacity ◽  
Random Variable ◽  
Friction Angle ◽  
Shallow Foundations ◽  
Cohesionless Soil ◽  
Unit Weight ◽  
Previous Solution ◽  
Probabilistic Solution ◽  
Two Parameter ◽  
Soil Unit

An exact probabilistic solution of the ultimate bearing capacity of cohesionless soil for shallow strip foundations is presented. The solution incorporates two random variables: effective friction angle [Formula: see text] and soil unit weight γ. This solution is an extension of a previous solution in which only [Formula: see text] is considered as a random variable. The exact solution is verified using Monte Carlo simulation and the sensitivity of the solution to the coefficient of variation of the soil unit weight is examined. Key words : probability, reliability, bearing capacity, shallow strip foundations, friction angle, soil unit weight.

Effect of Preloading on the Response of a Shallow Skirted Foundation

2014 ◽  
Author(s):  
Cristina Vulpe ◽  
Susan Gourvenec
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Small Strain ◽  
Significant Gain ◽  
Finite Element Analyses ◽  
Foundation Design ◽  
Degree Of Consolidation ◽  
Insight Into

The effect of preloading on the vertical settlement and bearing capacity of a circular skirted foundation was investigated as a function of relative preload and degree of consolidation by means of small strain finite element analyses. Significant gain in bearing capacity was observed for practical levels of preloads and duration of consolidation, offering an insight into potential efficiencies in foundation design.

The Research for the Technology of Inner Struck Pile and the Coefficient of Pile Endpoint Resistance

2012 ◽  
Vol 170-173 ◽  
pp. 335-338
Author(s):  
Xin Sheng Yin ◽  
Jing Wei Cai ◽  
Pang Feng Ba
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Small Area ◽  
New Technology ◽  
Friction Angle ◽  
Poisson's Ratio ◽  
Soil Parameters ◽  
Pile Head ◽  
Area Method ◽  
Finite Element Software

This document introduces a kind of new technology including testing pile, making pile, measuring pile----the technology of the inner struck pile. The mechanism for the inner struck piles and small area method for testing pile was explained. The coefficient of the pile endpoint resistance was calculated in different depth with the finite element software and it's variation was analyzed with different parameters' variation (cohesion, friction angle, elastic modulus, Poisson's ratio). The result shows that the value of the coefficients of the pile endpoint resistance reduces with the rising of the value of depth and the value is affected by the size of the pile head and the soil parameters.

A Method to Predict Embedded Trajectory Based on the Finite Element Analyses of Bearing Capacity of Drag Anchor

2018 ◽  
Author(s):  
Dongsheng Qiao ◽  
Muren Bao ◽  
Jun Yan ◽  
Daocheng Zhou ◽  
Yugang Li
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
System Design ◽  
Contact Friction ◽  
Mooring System ◽  
Finite Element Analyses ◽  
Position Information ◽  
Direction Parallel ◽  
Specific Position ◽  
Incremental Step

With the development of marine resources going to deeper water depth, the mooring system design becomes more important. Predicting the embedded trajectory of drag anchor during the installation process is very significant for calculating the ultimate pullout bearing capacity of drag anchor and the mooring system design. Firstly, the initial angle and embedded depth of drag anchor are assumed. Secondly, the drag anchor penetrates a unit displacement along the direction parallel to the anchor fluke at each incremental step, and the specific position information (horizontal, vertical, angle) could be obtained. Thirdly, the ultimate bearing capacity of drag anchor at this incremental step could be calculated using the two-dimensional and three-dimensional finite element model which considering the contact friction between the drag embedment anchor and seabed clay. And then, the new specific position information could be obtained according to the mechanical equilibrium equation of inverse catenary. Finally, the whole drag anchor embedded trajectory could be obtained when the drag angle between the anchor fluke and seabed tends to zero as a limit state. In this paper, a method of predicting embedded trajectory based on the finite element analyses of bearing capacity of drag anchor is established, which could be used as a reference for the practical engineering.

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