Influences of Pile Group Effects on Wave Forces on an Offshore Bridge Pile-Cap Foundation

In the construction projects, a pile group foundation is often utilized. The group of bored piles is usually installed relatively close to each other and joined at the top by a pile cap to hold up the loads. In other hand, a fast estimation of the groups of piles capacities are needed in the preliminary design and in other conditions of projects, such as a supervisor of projects want to estimate the capacities of the group of piles. The purpose of this research is to study the correlations of groups of piles efficiencies with the number of piles and to compare the groups of piles capacities with the single piles capacities. Furthermore, this study is aimed to make a fast estimation of groups of piles capacities using proposed graphical method.The piles efficiencies are calculated using several methods, such as Simplified Analysis, Converse-Labare [1][2], Los Angeles Group, Seiler - Keeney, Das, and Sayed - Baker. In order to calculate the groups of piles capacities, the capacities of single piles are needed. The singles piles capacities are taken from graphical method proposed by Djarwanti et al. (2015a and 2015b). Three graphical methods utilized are derived from the Briaud et al. (1985) , Reese and Wright (1977), and Reese O’Neill method. Moreover, the proposed graphical method is applied in the case study. The case study takes palace in Graha Indoland Condotel Inside Yogyakarta Construction Project.The pile efficiency graph is recommended for this research since the value of pile efficiency could be easily taken. The value of pile efficiency for Graha Indoland Condotel Inside using Simplified Analysis, Converse - Labare, Los Angeles Group, Seiler – Keeney, Das, and Sayed – Baker are 1,75; 0,89; 0,94; 0,99; 4,00; 1,56 respectively. Meanwhile the value of pile group capacity with the value of pile group efficiency more than 1, showed that the pile group capacity based on the efficiency is bigger than the one based on single down pattern.

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Lateral Load Capacity and Passive Resistance of Full-Scale Pile Group and Cap

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1736-04 ◽

2000 ◽

Vol 1736 (1) ◽

pp. 24-32 ◽

Cited By ~ 5

Author(s):

Kyle M. Rollins ◽

Andrew E. Sparks ◽

Kris T. Peterson

Keyword(s):

Load Capacity ◽

Pile Group ◽

Lateral Load ◽

Full Scale ◽

Dynamic Resistance ◽

Back Side ◽

Passive Resistance ◽

Passive Pressure ◽

Pile Cap ◽

Measured Resistance

Static and dynamic (statnamic) lateral load tests were performed on a full-scale 3 × 3 pile group driven in saturated low-plasticity silts and clays. The 324-mm outside diameter steel pipe piles were attached to a reinforced concrete pile cap (2.74 m square in plan and 1.21 m high), which created an essentially fixed-head end constraint. A gravel backfill was compacted in place on the back side of the cap. Lateral resistance was therefore provided by pile-soil-pile interaction as well as by base friction and passive pressure on the cap. In this case, passive resistance contributed about 40 percent of the measured static capacity. The measured resistance was compared with that computed by several techniques. The log-spiral method provided the best agreement with measured resistance. Estimates of passive pressure computed using the Rankine or GROUP p-y curve methods significantly underestimated the resistance, whereas the Coulomb method overestimated resistance. The wall movement required to fully mobilize passive resistance in the dense gravel backfill was approximately 0.06 times the wall height, which is in good agreement with design recommendations. The p-multipliers developed for the free-head pile group provided reasonable estimates of the pile-soil-pile resistance for the fixed-head pile group. Default p-multipliers in the program GROUP led to a 35 percent overestimate of pile capacity. Overall dynamic resistance was typically 100 to 125 percent higher than static; however, dynamic passive pressure resistance was over 200 percent higher than static.

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A variational approach for the analysis of pile group–pile cap interaction

Géotechnique ◽

10.1680/geot.2000.50.4.349 ◽

2000 ◽

Vol 50 (4) ◽

pp. 349-357 ◽

Cited By ~ 26

Author(s):

W. Y. Shen ◽

Y. K. Chow ◽

K. Y. Yong

Keyword(s):

Variational Approach ◽

Pile Group ◽

Pile Cap ◽

Group Pile

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An experimental investigation into pile group-layered soil interaction

The Journal of Strain Analysis for Engineering Design ◽

10.1243/03093247v315371 ◽

1996 ◽

Vol 31 (5) ◽

pp. 371-375

Author(s):

K Chandrashekhara ◽

S Joseph Antony ◽

J Mallikarjuna Reddy

Keyword(s):

Numerical Solutions ◽

Interaction Analysis ◽

Pile Group ◽

Layered Soil ◽

Single Pile ◽

Photoelastic Method ◽

Soil Medium ◽

Interaction Factor ◽

Pile Cap ◽

Soil Interface

An interaction analysis of an axially loaded single pile and pile group with and without a pile cap in a layered soil medium has been investigated using the two-dimensional photoelastic method. A study of the pile or pile group behaviour has been made, varying the pile cap thickness as well as the embedded length of the pile in the hard stratum. The shear stress distribution along the pile-soil interface, non-dimensionalized settlement values of the single pile and the interaction factor for the pile group have been presented. Wherever possible, the results of the present analysis have been compared with available numerical solutions.

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Experimental and Numerical Study of Laterally Loaded Pile Groups with Pile Caps at Variable Elevations

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1736-02 ◽

2000 ◽

Vol 1736 (1) ◽

pp. 12-18 ◽

Cited By ~ 2

Author(s):

Michael C. McVay ◽

Limin Zhang ◽

Sangjoon Han ◽

Peter Lai

Keyword(s):

Numerical Study ◽

Ground Surface ◽

Pile Group ◽

Special Device ◽

Pile Groups ◽

Finite Element Program ◽

Lateral Resistance ◽

Pile Cap ◽

Element Program ◽

Pile Caps

A series of lateral load tests were performed on 3×3 and 4×4 pile groups in loose and medium-dense sands in the centrifuge with their caps located at variable heights to the ground surface. Four cases were considered: Case 1, pile caps located above the ground surface; Case 2, bottom of pile cap in contact with the ground surface; Case 3, top of pile cap at the ground surface elevation; and Case 4, top of pile cap buried one cap thickness below ground surface. All tests with the exception of Case 1 of the 4×4 group had their pile tips located at the same elevation. A special device, which was capable of both driving the piles and raining sand on the group in flight, had to be constructed to perform the tests without stopping the centrifuge (spinning at 45 g). The tests revealed that lowering the pile cap elevation increased the lateral resistance of the pile group anywhere from 50 to 250 percent. The experimental results were subsequently modeled with the bridge foundation-superstructure finite element program FLPIER, which did a good job of predicting all the cases for different load levels without the need for soil–pile cap interaction springs (i.e., p-y springs attached to the cap). The analyses suggest that the increase in lateral resistance with lower cap elevations may be due to the lower center of rotation of the pile group. However, it should be noted that this study was for pile caps embedded in loose sand and not dense sands or at significant depths. The experiments also revealed a slight effect for the case of the pile cap embedded in sand with a footprint wider than the pile row. In that case the size of the passive soil wedge in front of the pile group, and consequently the group’s lateral resistance, increased.

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Effect of Seabed Slope on Offshore Pile Lateral Behaviour Under Wave Force

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 1 ◽

10.1115/omae2010-21164 ◽

2010 ◽

Author(s):

Sathyanarayanan Dhandapani ◽

Muthukkumaran Kasinathan

Keyword(s):

Finite Element ◽

Vertical Direction ◽

Pile Group ◽

Element Model ◽

Wave Force ◽

Wave Forces ◽

Extreme Conditions ◽

Offshore Platforms ◽

Wave Loads ◽

Offshore Structure

Fixed offshore platforms supported by pile foundations are required to resist dynamic lateral loading due to wave forces. The response of a jacket offshore tower is affected by the flexibility and nonlinear behavior of the supporting piles. In this study, a typical fixed offshore platform is chosen, and dynamic wave analysis is performed on it. Analysis has been performed for normal environmental conditions and extreme conditions. For the foundation, the deflections and reactions at regular intervals along the vertical direction from the seabed have been found out from the dynamic analysis, and the results have been compared for normal and extreme conditions. The aim of this study is to investigate the effects of the combined lateral and vertical loads on pile group foundation of a fixed offshore structure and the effects of seabed slope on the pile responses. To provide a more accurate and effective design for offshore pile foundation systems under axial structural loads and lateral wave loads, a finite element model which is modelled in FLAC3D is employed herein to determine the soil structure interaction under similar loading conditions. Three dimensional modelling and the analyses are done using FLAC3D — a finite element package.

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Dynamic Lateral Pile‐Group Effects

Journal of Geotechnical Engineering ◽

10.1061/(asce)0733-9410(1983)109:10(1267) ◽

1983 ◽

Vol 109 (10) ◽

pp. 1267-1285 ◽

Cited By ~ 7

Author(s):

Takaaki Kagawa

Keyword(s):

Pile Group ◽

Group Effects

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Fracture and Damage Mechanism of RC Pile Group Foundation under Low Reversed Cyclic Loading

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.452-453.665 ◽

2010 ◽

Vol 452-453 ◽

pp. 665-668

Author(s):

Mi Zhou ◽

Yue Zhang ◽

Wan Cheng Yuan

Keyword(s):

Damping Ratio ◽

Damage Model ◽

Damage Index ◽

Pile Group ◽

Element Model ◽

Damage Mechanism ◽

Loading Path ◽

Bond Slip ◽

Long Span ◽

Pile Cap

This document explains and demonstrates experimental activity on 4 scale-models of elevated pile cap foundation belonging to a long span continuous bridge. The foundation was composed of 9 piles, pile cap and pier and the special soil box was built to consider soil-pile-superstructure interaction. According to the test result, the development rule of the failure mode, the failure form, the load-displacement hysteretic loops and the plastic hinges mechanism etc. for specimens were summarized. Moreover, the energy dissipation capacity and the viscous damping ratio were gained. The test also provided the data to quantitatively assessment the positive effect of steel protective pipe for RC pile. Fiber beam-column finite element model considering the modified Park-Ang damage index was built in OpenSees. This damage model was proposed to consider the loading path, the pronounced pinching effect of concrete and bond-slip of the reinforcing bars in the paper. In calculation strength degradation and stiffness degradation effects were both embodied. The skeleton curves of test and numerical analysis are both consistent by comparing.

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