The Experts below are selected from a list of 5763 Experts worldwide ranked by ideXlab platform

Barry Lehane - One of the best experts on this subject based on the ideXlab platform.

  • relating Shaft Friction of buried piles and cpt resistance in clayey sands
    Geotechnique, 2020
    Co-Authors: L V Doan, Barry Lehane
    Abstract:

    This paper examines factors controlling the ultimate Shaft Friction developed on buried piles in normally consolidated clay–sand mixtures and explores the relationship between this Friction and the...

  • set up of pile Shaft Friction in laboratory chamber tests
    International Journal of Physical Modelling in Geotechnics, 2014
    Co-Authors: Jit Kheng Lim, Barry Lehane
    Abstract:

    Although field evidence of increases in pile Shaft Friction over time (i.e. set-up) in sand is compelling, the observations are highly scattered and the mechanisms leading to the increases are poorly understood. Several attempts have been made to model the phenomenon using small-scale physical models in a controlled environment, but the investigations were hampered by numerous restrictions. This paper describes an improved small-scale model pile experiment designed to investigate the ageing effects of pile Shaft Friction in sand. Details of the experimental set-up adopted and procedures employed are presented. Results show that the phenomenon of pile set-up is successfully modelled and that load–displacement characteristics are in keeping with those observed in centrifuge tests. Although the ageing effects observed in this laboratory-scale physical model may not be directly applicable to field scale piles, comparative studies involving various influential parameters provide qualitative indications of the ...

  • characterisation of the effects of time on the Shaft Friction of displacement piles in sand
    Geotechnique, 2014
    Co-Authors: Jit Kheng Lim, Barry Lehane
    Abstract:

    This paper describes a new approach to represent the effects of time on the Shaft Friction of displacement piles in sand. The proposal is based on the findings from pile test programmes performed at a test bed site in Western Australia in addition to data from well-documented full-scale pile tests. The investigation reveals a significant influence of installation disturbance on the subsequent gain in capacity (set-up) of Shaft Friction. Set-up is viewed as a recovery process, rather than a capacity gain, following the disturbance induced by pile installation. Gains in capacity in the medium and longer term tend to vary with the logarithm of time, while capacity changes shortly after installation are seen to be relatively small. A new expression is proposed to represent this ageing characteristic, which also incorporates a limiting (or maximum available) Shaft Friction.

  • Shaft capacity of displacement piles in clay using the cone penetration test
    Journal of Geotechnical and Geoenvironmental Engineering, 2013
    Co-Authors: Barry Lehane, Yunong Li, Ryan Williams
    Abstract:

    AbstractThe prediction of the Shaft capacity of displacement piles in clay still relies wholly on empirical or semiempirical approaches. This paper examines the predictive abilities of five well-known methods against an extended version of an existing database of pile tests. It is seen that coefficients of variation (COVs) of the ratio of calculated to measured capacities (Qc/Qm) are significantly higher than expected. The paper then uses the database of Shaft capacities to examine potential relationships between local Shaft Friction and the cone penetration test end resistance (qt). Predictions are subsequently compared with capacities measured in a series of centrifuge tests and with the distributions of peak Frictions observed in two well-documented field tests. Widely different formulations adopted by each of the existing empirical methods give broadly similar COV values for Qc/Qm ratios, and it is concluded that the database of high-quality pile tests needs to be expanded significantly if the reliabi...

  • Shaft Friction from instrumented displacement piles in an uncemented calcareous sand
    Journal of Geotechnical and Geoenvironmental Engineering, 2012
    Co-Authors: Barry Lehane, James A Schneider, Jit Kheng Lim, G Mortara
    Abstract:

    AbstractThe behavior of displacement piles in uncemented calcareous sand is investigated using field piles instrumented with a sensor that simultaneously records the radial stress and shear stress at specific locations on the pile Shafts. These tests are interpreted with the assistance of data from adjacent self-boring pressuremeter tests and from monotonic and cyclic direct shear interface tests performed on reconstituted samples. The existence of extremely low radial stresses on the pile Shafts is verified. Although dilation during shear is seen to compensate for such low radial stresses, short-term Shaft capacities are much lower than capacities of equivalent piles in siliceous sands. The development of a bonded or welded crust to the pile Shaft was seen to be the primary contributor to the setup observed at the test site; this crust forced failure to take place at a sand-sand rather than a sand-steel interface and also gave rise to higher levels of dilation during monotonic loading. The welded sand cr...

Mei Yin - One of the best experts on this subject based on the ideXlab platform.

  • Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle
    Frontiers of Structural and Civil Engineering, 2021
    Co-Authors: Yi Rui, Nicholas De Battista, Cedric Kechavarzi, Mei Yin
    Abstract:

    In this paper, we present an application of distributed fiber optic sensor (DFOS) technology to measure the strain of a continuous flight auger (CFA) test pile with a central reinforcement bar bundle, during a static load test carried out in London. Being distributed in nature, DFOS gives much more information about the pile performance as compared to traditional point sensors, such as identifying cross-sectional irregularities or other anomalies. The strain profiles recorded along the depth of the piles from the DFOS were used to calculate pile deformation (contraction), Shaft Friction, and tip resistance under various loads. Based on this pile load test, a finite element (FE) analysis was performed using a one-dimensional nonlinear load-transfer model. Calibrated by the Shaft Friction and tip resistance derived from the monitored data, the FE model was able to simulate the pile and soil performance during the load testing with good accuracy. The effect of the reinforcement cage and central reinforcement bar bundle were investigated, and it was found that the addition of a reinforcement cage would reduce the pile settlement by up to 20%.

Yi Rui - One of the best experts on this subject based on the ideXlab platform.

  • Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle
    Frontiers of Structural and Civil Engineering, 2021
    Co-Authors: Yi Rui, Nicholas De Battista, Cedric Kechavarzi, Mei Yin
    Abstract:

    In this paper, we present an application of distributed fiber optic sensor (DFOS) technology to measure the strain of a continuous flight auger (CFA) test pile with a central reinforcement bar bundle, during a static load test carried out in London. Being distributed in nature, DFOS gives much more information about the pile performance as compared to traditional point sensors, such as identifying cross-sectional irregularities or other anomalies. The strain profiles recorded along the depth of the piles from the DFOS were used to calculate pile deformation (contraction), Shaft Friction, and tip resistance under various loads. Based on this pile load test, a finite element (FE) analysis was performed using a one-dimensional nonlinear load-transfer model. Calibrated by the Shaft Friction and tip resistance derived from the monitored data, the FE model was able to simulate the pile and soil performance during the load testing with good accuracy. The effect of the reinforcement cage and central reinforcement bar bundle were investigated, and it was found that the addition of a reinforcement cage would reduce the pile settlement by up to 20%.

Nicholas De Battista - One of the best experts on this subject based on the ideXlab platform.

  • Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle
    Frontiers of Structural and Civil Engineering, 2021
    Co-Authors: Yi Rui, Nicholas De Battista, Cedric Kechavarzi, Mei Yin
    Abstract:

    In this paper, we present an application of distributed fiber optic sensor (DFOS) technology to measure the strain of a continuous flight auger (CFA) test pile with a central reinforcement bar bundle, during a static load test carried out in London. Being distributed in nature, DFOS gives much more information about the pile performance as compared to traditional point sensors, such as identifying cross-sectional irregularities or other anomalies. The strain profiles recorded along the depth of the piles from the DFOS were used to calculate pile deformation (contraction), Shaft Friction, and tip resistance under various loads. Based on this pile load test, a finite element (FE) analysis was performed using a one-dimensional nonlinear load-transfer model. Calibrated by the Shaft Friction and tip resistance derived from the monitored data, the FE model was able to simulate the pile and soil performance during the load testing with good accuracy. The effect of the reinforcement cage and central reinforcement bar bundle were investigated, and it was found that the addition of a reinforcement cage would reduce the pile settlement by up to 20%.

Cedric Kechavarzi - One of the best experts on this subject based on the ideXlab platform.

  • Distributed fiber optic monitoring of a CFA pile with a central reinforcement bar bundle
    Frontiers of Structural and Civil Engineering, 2021
    Co-Authors: Yi Rui, Nicholas De Battista, Cedric Kechavarzi, Mei Yin
    Abstract:

    In this paper, we present an application of distributed fiber optic sensor (DFOS) technology to measure the strain of a continuous flight auger (CFA) test pile with a central reinforcement bar bundle, during a static load test carried out in London. Being distributed in nature, DFOS gives much more information about the pile performance as compared to traditional point sensors, such as identifying cross-sectional irregularities or other anomalies. The strain profiles recorded along the depth of the piles from the DFOS were used to calculate pile deformation (contraction), Shaft Friction, and tip resistance under various loads. Based on this pile load test, a finite element (FE) analysis was performed using a one-dimensional nonlinear load-transfer model. Calibrated by the Shaft Friction and tip resistance derived from the monitored data, the FE model was able to simulate the pile and soil performance during the load testing with good accuracy. The effect of the reinforcement cage and central reinforcement bar bundle were investigated, and it was found that the addition of a reinforcement cage would reduce the pile settlement by up to 20%.