The Behavior of Piles Driven in Clay. II. Investigation of the Bearing Capacity Using Total and Effective Strength Parameters

This paper outlines research of large model piles and some full scale piles driven into insensitive clay to study the phenomenon of load transfer and the effect of pile driving on the soil. It is divided into two parts. Part I dealt with the stress field set up by driving a large model pile into an instrumented clay bed and the stresses measured for some full scale timber piles. Part II presents an evaluation of the load carrying capacity of the model pile and compares the results with full scale load tests. Soil properties are evaluated in terms of effective stress for an estimate of the bearing capacity of the piles.The short term bearing capacity of the pile shaft and base can be estimated by conventional methods based on the undrained shearing strength of the clay at the time of driving. However, after several load cycles and for long term bearing capacity, closer estimates are obtained by use of the effective skin friction and shearing strength parameters from drained tests. Previous bearing capacity theory can be used for estimating the ultimate base capacity and an approximate theory is presented to estimate the average effective radial stress on the pile shaft in connection with the ultimate shaft capacities. This proposed approach is supported by observations in some clays of low sensitivity, but requires further research in other types of clays.

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The Behavior of Piles Driven in Clay. I. An Investigation of Soil Stress and Pore Water Pressure as Related to Soil Properties

Canadian Geotechnical Journal ◽

10.1139/t72-039 ◽

1972 ◽

Vol 9 (4) ◽

pp. 351-373 ◽

Cited By ~ 25

Author(s):

J. I. Clark ◽

G. G. Meyerhof

Keyword(s):

Soil Properties ◽

Load Transfer ◽

Pore Water Pressure ◽

Water Pressure ◽

Full Scale ◽

Approximate Theory ◽

Model Pile ◽

Stress Changes ◽

Low Sensitivity ◽

Large Model

This paper outlines research on large model piles and some full-scale piles driven into insensitive clay to study the phenomena of load transfer and the effect of pile driving on the soil. It is divided into two parts. Part I deals with the stress field set up by driving a large model pile into an instrumented clay bed and the stresses measured for some full-scale timber piles. Part II presents an evaluation of the load carrying capacity of the model pile and compares the results with full-scale pile load tests. The soil properties are evaluated in terms of effective stress for an estimate of the bearing capacity of the piles.The measured soil displacements near the shaft and base agree well with plastic theory, while the observed magnitude of the pore pressures in the clay due to driving are smaller and the rate of pore pressure dissipation is greater than expected theoretically.The magnitude of the total and effective radial stresses surrounding the pile is mainly related to the stress changes in the soil due to placing the pile and subsequent stress changes are relatively small. On the other hand, the tangential and vertical stresses vary appreciably with time and the latter stresses depart considerably from estimates based on elastic theory, due to locked-in-soil stresses.An approximate theory is presented to estimate the average effective radial stress on the pile shaft in connection with the ultimate shaft capacity. This proposed approach is supported by observations in some clays of low sensitivity, but requires further research in other type of clays.

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FULL SCALE STATIC LOAD TEST ON THE SPIDER NET SYSTEM

Jurnal Teknologi ◽

10.11113/jt.v77.6424 ◽

2015 ◽

Vol 77 (11) ◽

Author(s):

Helmy Darjanto ◽

Masyhur Irsyam ◽

Sri Prabandiyani Retno

Keyword(s):

Bearing Capacity ◽

Load Transfer ◽

Static Load ◽

Full Scale ◽

Load Test ◽

Static Load Test ◽

Specific Element ◽

Soil Stratum ◽

Applied Loading ◽

Shallow Footing

The Spider Net System Footing (SNSF) is a raft foundation system that commonly used in Indonesia. It contains a plate, downward ribs system for reinforcement, and the compacted filled soil. The ribs are in longitudinal and transversal, called as settlement rib and in diagonal direction, named as construction rib. This paper explores the load transfer mechanism along the plate, the ribs, filled soil and the base soil under the footing system. The mechanism is investigated by conducting full scale static load test on SNSF. Strain gauges were installed to monitor the strain increment of each footing elements during loading. 3D numerical analysis was also conducted to verify the experimental results. To analyze the results, Load-Ultimate Ratio Factor (L-URF) was proposed. L-URF was a ratio between ultimate soil bearing capacity of the SNSF and the applied loading at specific element. Higher the L-URF value means higher loading applied at its associate element. Both experimental and numerical results show that at the first stage the loading was fully carried out by the tip of the ribs and transferred to the soil stratum under the footing system. Increasing the loading, the ribs, plate, and filled soil altogether sustain the loading and then transferred to the soil stratum below the footing system. The results also affirm that SNSF generate higher bearing capacity compare with simple shallow footing.

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Axial compressive capacity of helical piles from field tests and numerical study

Canadian Geotechnical Journal ◽

10.1139/cgj-2012-0487 ◽

2013 ◽

Vol 50 (12) ◽

pp. 1191-1203 ◽

Cited By ~ 36

Author(s):

Zeyad H. Elsherbiny ◽

M. Hesham El Naggar

Keyword(s):

Bearing Capacity ◽

Load Transfer ◽

Numerical Study ◽

Numerical Models ◽

Field Tests ◽

Reduction Factor ◽

Full Scale ◽

Cohesionless Soil ◽

Soil Parameters ◽

Helical Piles

The compressive capacity of helical piles in sand and clay is investigated by means of field testing and numerical modeling. The numerical models are conducted using the computer program ABAQUS and are calibrated and verified using full-scale load testing data. The calibration was accomplished by using reasonable assumptions regarding soil–pile interaction and soil parameters reported from the literature. The model was verified by comparing its predictions with observed load–displacement curves obtained from full-scale pile load tests. The verified numerical model was used to perform a parametric study considering different pile configurations and soil parameters to evaluate the compressive capacity and load-transfer mechanism of helical piles. The compressive capacity obtained from the numerical models is compared with that obtained from existing theoretical methods for calculating the capacity. It is found that the predictions of theoretical equations for piles in cohesionless soil vary largely depending on the choice of bearing capacity factors and proper failure criteria. The interaction of closely spaced helices on the capacity of a helical pile is also evaluated. A bearing capacity reduction factor, R, and helix efficiency factor, EH, are proposed to evaluate the compressive capacity of helical piles in cohesionless soil considering an industry-acceptable ultimate load criterion corresponding to settlement equal to 5% of helix diameter, D.

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A Full-Scale Field Study on Bearing Characteristics of Cast-in-Place Piles with Different Hole-Forming Methods in Loess Area

Advances in Civil Engineering ◽

10.1155/2019/1450163 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Zhijun Zhou ◽

Tao Yang ◽

Haobo Fan

Keyword(s):

Bearing Capacity ◽

Field Study ◽

Load Transfer ◽

Full Scale ◽

Rotary Drilling ◽

Loess Area ◽

Side Resistance ◽

Attenuation Rate ◽

Scale Field ◽

Forming Methods

This paper presents the results from a full-scale field study on the 3 different types of cast-in-place piles: rotary drilling piles (RDPs), manual digging piles (MDPs), and impact drilling piles (IDPs), for a bridge construction project of Wuqi–Dingbian Expressway, in Shaanxi. The results indicate that under the similar conditions, MDP exhibits the largest bearing capacity (11000 kN) in the loess area, followed by RDP (9000 kN) and IDP (8000 kN). And all tested values exceed the estimated value (7797.9 KN), indicating that the calculation formula of bearing capacity recommended by the Chinese standard is safe and conservative. During the load transfer process, the axial force attenuation rate of the pile body increases with pile side resistance. The average attenuation rate of MDP is the largest (24.2%), followed by RDP (19.72%) and IDP (16.69%). The bearing characteristics of these test piles are mainly pile side resistance, but the manual digging method created the least amount of disturbance to the soil around the pile, and due to its hole wall being rough, this enhances the pile-soil interactions. Hole-forming methods mainly affect the exertion of pile side resistance compared with pile end resistance. In view of pile side resistance and pile end resistance not taking effect at the same time, degree of exertion of these 2 resistances should be considered when designing cast-in-place piles in loess areas, and different partial coefficients should be used.

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MECHANISM OF THE BEARING CAPACITY OF THE OPEN-ENDED PILES USING DOUBLE-PIPE MODEL PILE

Journal of Japan Society of Civil Engineers Ser B3 (Ocean Engineering) ◽

10.2208/jscejoe.75.i_462 ◽

2019 ◽

Vol 75 (2) ◽

pp. I_462-I_467

Author(s):

Hiroyoshi YAMAZAKI ◽

Yoshiaki KIKUCHI ◽

Shohei NODA ◽

Kazuki SAKIMOTO ◽

Hiroki MATSUOKA

Keyword(s):

Bearing Capacity ◽

Pipe Model ◽

Model Pile ◽

Double Pipe

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ANALYTICAL AND NUMERICAL METHODS FOR DETERMINING THE CARRYING CAPACITY OF A PILE BARETT ON WEAK SOILS IN DEEP PITS

International Journal for Computational Civil and Structural Engineering ◽

10.22337/2587-9618-2021-17-3-94-101 ◽

2021 ◽

Vol 17 (3) ◽

pp. 94-101

Author(s):

Rashid Mangushev ◽

Nadezhda Nikitina ◽

Hieu Le Trung ◽

Ivan Tereshchenko

Keyword(s):

Bearing Capacity ◽

Numerical Test ◽

Full Scale ◽

Construction Site ◽

Weak Soils ◽

Geological Conditions ◽

Full Scale Tests ◽

Soil Excavation ◽

Deep Pits ◽

The City

The article provides an analysis of the bearing capacity of barrett piles in difficult geological conditions at a construction site in the city of Hanoi, Vietnam based on the results of analytical calculations according to Russian building codes, mathematical modeling and field full-scale tests. The paper describes a numerical test of a single barrette for Mohr-Coulomb and Hardening Soil models in the Midas GTS NX software package. The bearing capacity of a barrette in soft soils is also proposed to be determined by an analytical solution for calculating the settlement of a single pile, taking into account the unloading of the pit after soil excavation. The results of full-scale tests at the site of future construction, graphs of "load-settlement" of the barrette head from the applied vertical load and the general assessment of the bearing capacity of the barret pile by various methods are shown.

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A Full-Scale Experimental Study of the Vertical Dynamic and Static Behavior of the Pier-Cap-Pile System

Advances in Civil Engineering ◽

10.1155/2020/9430248 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Jianlei Liu ◽

Meng Ma ◽

Flavio Stochino

Keyword(s):

Experimental Study ◽

Bearing Capacity ◽

Dynamic Stiffness ◽

Soil Layer ◽

Low Frequency ◽

Full Scale ◽

Single Pile ◽

Static Stiffness ◽

Loading Test ◽

Test Technique

The bearing capacity evaluation of bridge substructures is difficult as the static loading test (SLT) cannot be employed for the bridges in services. As a type of dynamic nondestructive test technique, the dynamic transient response method (TRM) could be employed to estimate the vertical bearing capacity when the relationship between static stiffness and dynamic stiffness is known. The TRM is usually employed to evaluate single piles. For the pier-cap-pile system, its applicability should be investigated. In the present study, a novel full-scale experimental study, including both TRM test and SLT, was performed on an abandoned bridge pier with grouped pile foundation. The test included three steps: firstly, testing the intact pier-cap-pile system; then, cutting off the pier and testing the cap-pile system; finally, cutting off the cap and testing the single pile. The TRM test was repeatedly performed in the above three steps, whereas the SLT was only performed on the cap-pile system. Based on the experimental results, the ratio of dynamic and static stiffness of the cap-pile system was obtained. The results show that (1) in the low-frequency range (between 10 and 30 Hz in this study), the dynamic stiffness of the whole system is approximately four times of that of a single pile; (2) the ratio of dynamic and static stiffness of the cap-pile system tested in the study is approximately 1.74, which was similar to other tested values of a single pile; (3) to evaluate the capacity of similar cap-pile system and with similar soil layer conditions by TRM, the value of Kd/Ks tested in the study can be used as a reference.

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Bi-Directional Static Load Tests of Pile Models

Applied Sciences ◽

10.3390/app10165492 ◽

2020 ◽

Vol 10 (16) ◽

pp. 5492

Author(s):

Michał Baca ◽

Włodzimierz Brząkała ◽

Jarosław Rybak

Keyword(s):

Bearing Capacity ◽

Static Load ◽

Load Testing ◽

Pile Capacity ◽

Pile Shaft ◽

Load Tests ◽

S Curve ◽

Definition Of ◽

Standard Tests ◽

Static Load Testing

This work examined a new method of bi-directional static load testing for piles, referencing the Osterberg test. Measurements were taken, on a laboratory scale, using six models of piles driven into a box filled with sand. This method allowed for separate measurements of pile base and pile shaft bearing capacities. Based on the results, the total pile bearing capacity and equivalent Q–s diagrams were estimated. The results obtained show that the structure of the equivalent curve according to Osterberg is a good approximation of the standard Q–s curve obtained from load tests, except for loads close to the limit of bearing capacity (those estimates are also complicated by the inapplicability and ambiguity of a definition of the notion of limit bearing capacity); the equivalent pile capacity in the Osterberg method represents, on average, about 80% of the capacity from standard tests.

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Analytical modelling of a three-layer wall system of strengthening for large-panel slab buildings by means of bonded anchors

MATEC Web of Conferences ◽

10.1051/matecconf/201817404012 ◽

2018 ◽

Vol 174 ◽

pp. 04012

Author(s):

Jerzy K. Szlendak ◽

Agnieszka Jablonska-Krysiewicz ◽

Dariusz Tomaszewicz

Keyword(s):

Bearing Capacity ◽

Analytical Models ◽

Simultaneous Action ◽

Strength Parameters ◽

Load Bearing Capacity ◽

Load Bearing ◽

Pull Out ◽

Large Panel ◽

Wall System ◽

New System

The goal of the article is to elaboration analytical models describing a new system of reinforcing three-layer walls of large-panel buildings with bonded anchors. The use of this type of fasteners that bond the façade texture layer to the structural slab is necessary due to the low durability of previously used suspension elements. Various bonded anchorage systems were considered. The new anchorage systems were designed as two-anchors systems (horizontal anchor and diagonal anchors) and three-anchors systems (horizontal anchor and two diagonal anchors). The inclinations of these anchors are in the range of 30°-60° in relation to the surface of the element. For the above types of reinforcements, analytical models have been developed that take into account the change of strength parameters of the resin and steel from which the anchors were made, the interaction of materials resin-steel and resin-concrete and the effect of the simultaneous action of pull-out and shearing forces. Moreover, was assumed the simultaneous destruction of fasteners two- and three-anchors. The elaborated analytical models will be used to determine the load-bearing capacity of the new connector system, which will allow the elaboration of guidelines for strengthening three-layer walls of largepanel slab buildings.

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