• Coupled systems mechanics
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• v.3 no.4
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• pp.367-384
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• 2014

The study deals with the physical modeling of a typical single storeyed building frame resting on pile foundation and embedded in cohesive soil mass using the finite element based software SAP-IV. Two groups of piles comprising two and three piles, with series and parallel arrangement thereof, are considered. The slab provided at top and bottom of the frame along with the pile cap is idealized as four noded and two dimensional thin shell elements. The beams and columns of the frame, and piles are modeled using two noded one dimensional beam-column element. The soil is modeled using closely spaced discrete linear springs. A parametric study is carried out to investigate the effect of various parameters of the pile foundation, such as spacing in a group and number of piles in a group, on the response of superstructure. The response considered includes the displacement at the top of the frame and bending moment in columns. The soil-structure interaction effect is found to increase the displacement in the range of 38 -133% and to increase the absolute maximum positive and negative moments in the column in the range of 2-12% and 2-11%. The effect of the soil- structure interaction is observed to be significant for the type of foundation and soil considered in this study. The results obtained are compared further with those of Chore et al. (2010), wherein different idealizations were used for modeling the superstructure frame and sub-structure elements (foundation). While fair agreement is observed in the results in either study, the trend of the results obtained in both studies is also same.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.5-15
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• 2015

The GCP (Granular Compaction Pile) for the improvement objective of soft ground has been frequently studied. However, these studies were the results deduced on the basis of the numerical analysis and the laboratory model tests, and there was no study method to apply the effects of the bulging failure of a flexible pile. In this study, the sensitivity of the load-settlement curves of the uniform and the tapered GCP dependant on the geotechnical parameters estimated from N value of standard penetration test (SPT) was analyzed. It was estimated reasonably that, in the very soft clay soil (N=3 or less), elastic modulus was 700~2000 kPa and Poisson's ratio was 0.40~0.48.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.95-101
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• 2009

As buildings increase in height, lifting plans are becoming increasingly important on construction sites. As a critical piece of load-lifting equipment, the tower crane deserves a well thought-out stability review, since it has a significant impact and is very vulnerable to structural safety disaster. To ensure the structural stability of a tower crane, its lateral support or pile supported foundation designs must include consideration for stability, and pile foundation must be used if site conditions prevent soil from providing the required bearing capacity, or prevent the foundation from being increased to the required extent. Pile supported foundation design requires thorough and systematic review, as more stability parameters need to be considered than with an independent foundation. This paper intends to develop an optimal design algorithm that can minimize associated costs while ensuring the fundamental stability of pile supported foundation design, limiting the scope of research to fixed-type trolley tower cranes using pile supported foundations. The findings herein on pile foundation stability review parameters, process and optimal design are expected to improve the operational efficiency of staff concerned, and reduce the time and efforts required for pile foundation design.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1802-1807
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• 2004

When a construction company builds a high structure, many piles should be driven into the ground by a hammer whose weight is 7,000 Kg in order to make the ground under the structure safe and strong. So, it is essential to determine whether a pile is penetrated into the ground enough to support the weight of the structure since ground characteristics at different locations are different each other. This paper proposes a visual measurement system for pile rebound and penetration movement including vibration using a high-speed line-scan camera and a specially designed mark to recognize two-dimensional motion parameters of the mark using only a line-scan camera. A mark stacking white and black right-angled triangles is used for the measurement, and movement information for vertical distance, horizontal distance and rotational angle is determined simultaneously

• Geomechanics and Engineering
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• v.3 no.1
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• pp.29-43
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• 2011

In this paper a semi-analytical approach is proposed to study the lateral behavior of a piled footing under horizontal loading. As accurate computation of stresses is usually needed at the interface separating the footing (pile) and the soil, this important location should be appropriately modeled as zero-thickness joint element. The piled footing is embedded in elastic soil with either homogeneous modulus or modulus proportional to depth (Gibson's soil). As the pile is the principal element in the piled footing system, a limited parametric study is carried out in order to investigate the influence of footing dimensions and the interface conditions on the lateral behavior of the pile. Hence, the pile behavior is examined through its main governing parameters, namely, the lateral displacement profiles, the bending moments, the shear forces and the soil reactions. The numerical results are presented for Poisson's ratio of 0.2 to represent a large variety of sands and Poisson's ratio of 0.5 to represent undrained clays.

• Geomechanics and Engineering
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• v.7 no.6
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• pp.679-703
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• 2014

This paper investigates nonlinear response of 51 laterally loaded rigid piles in sand. Measured response of each pile test was used to deduce input parameters of modulus of subgrade reaction and the gradient of the linear limiting force profile using elastic-plastic solutions. Normalised load - displacement and/or moment - rotation curves and in some cases bending moment and displacement distributions with depth are provided for all the pile tests, to show the effect of load eccentricity on the nonlinear pile response and pile capacity. The values of modulus of subgrade reaction and the gradient of the linear limiting force profile may be used in the design of laterally loaded rigid piles in sand.

• Structural Engineering and Mechanics
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• v.83 no.3
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• pp.377-386
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• 2022

This paper considers dynamic impedance functions and presents a detailed analysis of the soil plasticity influence on the pile-group foundation dynamic response. A three-dimensional finite element model is proposed, and a calculation method considering the time domain is detailed for the nonlinear dynamic impedance functions. The soil mass is modeled as continuum elastoplastic solid using the Mohr-Coulomb shear failure criterion. The piles are modeled as continuum solids and the slab as a structural plate-type element. Quiet boundaries are implemented to avoid wave reflection on the boundaries. The model and method of analysis are validated by comparison with those published on literature. Numerical results are presented in terms of horizontal and vertical nonlinear dynamic impedances as a function of the shear soil parameters (cohesion and internal friction angle), pile spacing ratio and frequencies of the dynamic signal.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.267-275
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• 2009

The steel pipe of steel-concrete composite piles increases the pile strength and induces the ductile failure by constraining the deformation of the inner concrete. In this research, the load-movement relations and the reinforcement effect by the outer steel pipe in the steel-concrete composite pile were analyzed by performing three-dimensional numerical analyses, which can simulate the yielding behavior of the pile material and the elasto-plastic behavior of soils. The parameters analyzed in the study include three pile materials of steel, concrete and composite, pile diameter and loading direction. As the results, the axial capacity of the composite pile was 1.9 times larger than that of the steel pipe pile and similar with that of the concrete pile. At the allowable movement criteria, the horizontal capacity of the composite pile was 1.46 times larger than that of the steel pile and 1.25 times larger than that of the concrete pile. In addition, the horizontal movement at the pile head of the composite pile was about 78% of that of the steel pile and about 53% of that of the concrete pile, which showed that the movement reduction effect of the composite pile was significant and enables the economical design of drilled shafts.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.366-373
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• 2002

This paper describes the load distribution and settlement of rockbolted-drilled shafts subjected to axial and lateral loads with the view to shortening the embedded depth of the pile shaft. The emphasis was on quantifying the reinforcing effects of rockbolts placed from the shafts to surrounding weathered rocks based on small-scale model tests peformed on instrumented piles. The major influencing parameters on reinforcing drilled shaft behavior are the number, the positions on the shaft, the grade, and the inclination angle at which the rockbolts are placed. The model tests was 1/40 scaled simulations of the behavior of the drilled shafts with varying combinations of the major influencing parameters. The incremental effects of reinforcement based on the various parameters have been weighed against load transfer characteristics before and after rockbolt installations.

• Structural Engineering and Mechanics
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• v.49 no.1
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• pp.95-110
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• 2014

The study deals with physical modeling of space frame-pile foundation and soil system using finite element models. The superstructure frame is analyzed using complete three-dimensional finite element method where the component of the frame such as slab, beam and columns are descretized using 20 node isoparametric continuum elements. Initially, the frame is analyzed assuming the fixed column bases. Later the pile foundation is worked out separately wherein the simplified models of finite elements such as beam and plate element are used for pile and pile cap, respectively. The non-linear behaviour of soil mass is incorporated by idealizing the soil as non-linear springs using p-y curve along the lines similar to that by Georgiadis et al. (1992). For analysis of pile foundation, the non-linearity of soil via p-y curve approach is incorporated using the incremental approach. The interaction analysis is conducted for the parametric study. The non-linearity of soil is further incorporated using iterative approach, i.e., secant modulus approach, in the interaction analysis. The effect the various parameters of the pile foundation such as spacing in a group and configuration of the pile group is evaluated on the response of superstructure owing to non-linearity of the soil. The response included the displacement at the top of the frame and bending moment in columns. The non-linearity of soil increases the top displacement in the range of 7.8%-16.7%. However, its effect is found very marginal on the absolute maximum moment in columns. The hogging moment decreases by 0.005% while sagging moment increases by 0.02%.