Lateral Pile Load Research Articles

Monotonic and cyclic lateral loading of piles in low- to medium-density chalk

Offshore and other structures often rely on driven piles to carry lateral loads. However, there is currently no established design method to cover lateral loading at chalk sites, which are widespread across Northwest Europe. This paper reports monotonic and cyclic lateral load tests on highly instrumented 508 mm and 1220 mm diameter. open steel piles driven at a well-characterised chalk test site in Kent, UK, for a recent joint industry project that developed new benchmark datasets and analyses, supported by high-quality testing. The ultimate lateral pressures mobilised in the chalk are shown to be relatively low compared to its uniaxial compressive strengths (UCS) due to pile-driving damage, natural fracturing, local yielding and brittleness. Significant gaps opened between the piles and chalk during loading, that led to a substantially softer response on unloading and subsequent reloading, as well as marked axial capacity losses. Reaction curves extracted from the field measurements and applied in a one-dimensional numerical model perform well in reproducing the monotonic lateral tests. As with piles driven in other materials, one-way cyclic lateral loading led to permanent displacement accumulation and stiffness changes that were linked to the cyclic loading parameters. Both effects were more marked under biaxial cyclic lateral loading.

Direct Field Curve Fitting Method to Determine Hardening Soil Parameter for Geotechnical Projects

Abstract In a wide archipelago country like Indonesia, transporting soil samples for laboratory tests are quite a bit of challenge in terms of cost and time as those need to be transported for weeks to nearest big cities. In-situ tests and correlation methods can be used as an alternative solution for preliminary or detailed design beside having on site laboratory. Correlating in-situ test results to hardening soil parameter (e.g. E 50) is common but it is not clear how those should be adjusted for Plaxis input. Two deep excavation projects and a lateral pile load test are used to see the performance of direct field curve fitting method utilizing SPT correlation to HS parameter. From the analysis, using E 50=4000N for clay soils and E 50=2800N for sand soils as upper bound parameters produce the best results with lesser discrepancy with the field measurements compared to calculations with lower bound parameters. For the deep excavation cases (Case 1 and Case 2), calculated lateral displacement results using upper bound parameters overestimates inclinometers measurement for less than 1.5 cm for both cases. For the case of lateral pile load test (Case 3), calculation using upper bound parameters succeed to capture a high detail of unloading-reloading curves similar to the actual measurement. This method can be used as a technique to design geotechnical projects and it proposes a framework for future research regarding a new possibility to establish various E 50 correlations.

Static lateral pile analysis of Dubai sedimentary rock in UAE

Analysis and calculation of lateral pile load capacities using appropriate methods is a challenging task for geotechnical engineers. Primarily, piles in Dubai, UAE, are rock fully socketed with top strata of medium dense to dense silty sand or sedimentary rock resisting lateral loads. In this study, the results of two field pile lateral load tests were chosen for examining different methods used by local geotechnical engineers, where ground lithology constitutes fragile sandstone up to ∼8 m below ground level overlying extremely weak conglomerate/siltstone. Assessing the efficacy of design parameters and analysis methodology is a pivotal aspect in preliminary evaluation of the lateral load capacity of piles. In this research, two commonly adopted approaches (non-linear p–y analysis using the LPile software and finite-element analysis using the Plaxis 3D software) were assessed by comparing them with field test results to predict the lateral load capacity precisely. Design parameters were based on borehole data and laboratory tests near the test location. Even though finite-element analysis predicted better than non-linear p–y analysis, lateral load capacities were underestimated in both piles analysed, which was related to assessment of input parameters. In addition, finite-element analysis was used to back-calculate the elastic modulus of rock that yields lateral deflections of piles close to field test results.

Deriving a p-y curve from lateral pile load tests – Case studies in alluvial OC clays

Estimating lateral pile capacity is one of the most typical works for geotechnical engineers. Although it has been a routine calculation, obtaining reliable results is still challenging, especially when the ground condition is unfamiliar. Fortunately, the lateral pile capacity prediction can be performed by deriving a p-y curve from the load-deformation curve measured during pile testing. In cases where a preliminary test pile exists, fortunately, the p-y curve can be generated easily using a subgrade reaction approach suggested by Davisson and Gill (1963). Two lateral pile load test results were used to show the prospect of this method for practical applications. The field tests were on driven and bored piles with different diameters and lengths embedded in alluvial OC clays at two different sites in Jakarta, Indonesia, where both piles were categorised as long piles. Derivation of p-y curves was performed with a simple spreadsheet. Then, the obtained p-y response was used to estimate the load-deformation curve. Results showed that the back-calculated curve agree well with the measured data. This outcome might be because the p-y curves were directly derived from the field test where the pile experienced in-situ stress, resulting in a more representative of the actual condition.

Soil-structure pile foundation interaction model due to lateral loading

Experimental research on piles, by models and physical tests on a laboratory scale, using materials and sizes that are different from the prototypes. The model is designed, treated, and interpreted the results of observing the response based on similarity using Model theory, but the soil sample cannot be modeled with model theory, giving rise to doubts similarity of the research. This study was conducted to examine the effect of pile-soil interaction on several views of the elastic modulus of the soil due to lateral loads. Laboratory model pile foundations are laterally loaded, on soil samples in a test box. The deflection of the pile foundation is analyzed based on the use of linear, layered, and non-linear modulus of elasticity. A non-linear simulation of the Winkler model with a spring along the depth of the pile was carried out to calibrate the horizontal deflection of the laboratory experimental model. The results showed that the Winkler model's modulus of elasticity was approximately 40% of the pile length, and the non-linear difference between the Winkler and laboratory models was 10.77%, comparisons can be conclusive about the need for similar research on lateral loading of laboratory model piles. The analysis also noted that the surface deflection was determined by winkler’s model elastic modulus analysis with an excess of about 12% to 14% in the first 10% of the pile length.

Assessment of Lateral Load Capacity of Single Pile at Bettiah Site: A Parametric Study

Pile foundations are widely used and accepted approach to transfer superstructure load to a deeper and stronger stratum. This work has been focused on the assessment of the effect of different parameters associated with piles such as pile diameter, pile length, grade of concrete and pile head condition (i.e., free or fixed) on the lateral load capacity. To evaluate the lateral load capacity considering the aforementioned parameters ‘IS Code’ and ‘Matlock and Reese’ methodologies have been utilized. The soil exploration data has been collected from ten different boreholes near to the railway bridge at Bettiah site, Bihar. The results of lateral pile load at different boreholes reflects that the lateral load capacity of pile significantly increased with the increase of pile diameters and grades of concrete. The lateral load capacity of pile was increased approximately by 13%, from both IS Code and Matlock and Reese methods, when the grade of concrete was increased from M25 to M40. It was also found that the condition of pile head also plays a major role in lateral load capacity. The lateral load capacity of pile obtained from IS code method under fixed head condition was found to be higher as compared to free head condition. It has also been observed that the lower values of ultimate lateral load capacity for fixed head and lower values for free head condition was obtained by IS Code as compared to Matlock and Reese method.

Effect of the pile diameter and slope on the undrained lateral response of the Large–Diameter pile

A new p–y curve of the lateral static loading of large diameter piles in cohesive slopes is proposed in this paper, which considers both the size effect and slope inclination. A series of pile size and slope inclination varied three–dimensional finite difference analyses are used to study the behavior of large–diameter pile foundations under lateral loading on cohesive sloping ground. Based on the results of numerical calculations, the pile–soil failure mechanism is discussed for large–diameter piles. Combined with the failure mechanism, nonlinear analytical formulations are derived for the ultimate lateral load and initial stiffness of hyperbolic p–y curves at different depths, which considers both the size effect and slope inclination. The proposed p–y curve is compiled into a program for parametric analysis of pile displacement and bending moment. To verify the proposed p–y curve, it is compared with large–scale foundation lateral loading field test and centrifuge test data to obtain a remarkable result.

Discussion of “Validation of Monotonic and Cyclic p-y Framework by Lateral Pile Load Tests in Stiff, Overconsolidated Clay at the Haga Site” by Youhu Zhang, Knut H. Andersen, Philippe Jeanjean, Kjell Karlsrud, and Torgeir Haugen

Discussion of “Validation of Monotonic and Cyclic p-y Framework by Lateral Pile Load Tests in Stiff, Overconsolidated Clay at the Haga Site” by Youhu Zhang, Knut H. Andersen, Philippe Jeanjean, Kjell Karlsrud, and Torgeir Haugen

Closure to “Validation of Monotonic and Cyclic p-y Framework by Lateral Pile Load Tests in Stiff, Overconsolidated Clay at the Haga Site” by Youhu Zhang, Knut H. Andersen, Philippe Jeanjean, Kjell Karlsrud, and Torgeir Haugen

Closure to “Validation of Monotonic and Cyclic p-y Framework by Lateral Pile Load Tests in Stiff, Overconsolidated Clay at the Haga Site” by Youhu Zhang, Knut H. Andersen, Philippe Jeanjean, Kjell Karlsrud, and Torgeir Haugen

Monotonic laterally loaded pile testing in a stiff glacial clay till at Cowden

This paper describes the results obtained from a field testing campaign on laterally loaded monopiles conducted at Cowden, UK, where the soil consists principally of a heavily overconsolidated glacial till. These tests formed part of the PISA project on the development of improved design methods for monopile foundations for offshore wind turbines. Results obtained for monotonic loading tests on piles of three different diameters (0·273 m, 0·762 m and 2·0 m) are presented. The piles had length-to-diameter ratios (L/D) of between 3 and 10. The tests included the application of monotonic loading incorporating periods of constant load to investigate creep effects, and investigations on the influence of loading rate. Data are presented on measured bending moments and inclinations induced in the piles. Inferred data on lateral displacements of the embedded section of the piles are determined using an optimised structural model. These field data support the development of a new one-dimensional modelling approach for the design of monopile foundations for offshore wind turbines. They also form a unique database of field measurements in an overconsolidated clay, from lateral loading of piles at a vertical distance above the ground surface.

Monotonic laterally loaded pile testing in a dense marine sand at Dunkirk

The results obtained from a field testing campaign on laterally loaded monopiles, conducted at a dense sand site in Dunkirk, northern France are described. These tests formed part of the PISA project on the development of improved design methods for monopile foundations for offshore wind turbines. Results obtained from monotonic loading tests on piles of three different diameters (0·273 m, 0·762 m and 2·0 m) are presented. The piles had length-to-diameter ratios (L/D) of between 3 and 10. The tests consisted principally of the application of monotonic loads, incorporating periods of held constant load to investigate creep effects. The influence of loading rate was also investigated. Data are presented on the overall load–displacement behaviour of each of the test piles. Measured data on bending moments and inclinations induced in the piles are also provided. Inferences are made for the displacements in the embedded length of the piles. These field data will support the development of a new one-dimensional modelling approach for the design of monopile foundations for offshore wind turbines. They also form a unique database of field measurements in a dense sand, from lateral loading of piles at a vertical distance above the ground surface.

Validation of Monotonic and Cyclic p-y Framework by Lateral Pile Load Tests in Stiff, Overconsolidated Clay at the Haga Site

AbstractPile foundations supporting offshore structures, such as jacket platforms and wind turbines, are subjected to cyclic lateral loading. The capacity and deformation of these pile foundations ...

Review on Lateral Stability of Piled Riverine Structures in the Estuaries of Sarawak

Soft soil conditions with very soft and deep silty clay have constantly endangered the stability of the riverine and estuarine structures in Sarawak. There have been many failures of jetties, wharves and bridges in Sarawak. In many cases of failures, the piles were not designed to resist the lateral movement, unless they were included to stabilize unstable slopes or potential landslides. This practice may be due to reasons such as erroneously judging the river bank as stable in slope stability analysis or simply due to the inexperience of designers. Also, when the river bank approaches the limiting stability in its natural state any construction activity on the river bank could result in lateral soil movement. This paper highlights this important geotechnical problem in Sarawak. Then it presents the details of a few failures of estuarine structures. A review of situations causing lateral loading of piles is then presented. The results of the in-soil and in-pile displacement measurements are shown in this paper and it is found that the computation made to compare between field and 3D modeling is agreeable.

Horizontal Displacement Control in Course of Lateral Loading of a Pile in a Slope

Standard procedures concerning axial and lateral capacity testing of foundation piles usually consist of a single loading cycle. Constant load steps or constant settlement increments may be applied in the test. Such a procedure significantly differs from in-situ conditions of pile loading, which can be cyclic – especially in the case of the constructions, which are subject to wind load. Several tests were performed to observe the behaviour of the driven piles subject to fast cyclic loading in horizontal direction (lateral load). The manner in which the load tests were performed made it possible to determine the displacement of the 40×40 cm pile in the least favourable loading scheme, i.e. the lateral load capacity of the pile oriented towards the embankment slope. The piles were originally designed for the foundation of noise barriers along the highway. Some of the piles were broken in course of driving and a cautious check of their behaviour under load was requested before the assembling of the entire structure. Eight load tests were carried out altogether. While selecting the piles for further load tests, the representativeness of the random sample was taken into account. The piles with diverse cross section and length were chosen, on the basis of the previous low strain tests of their integrity. The subsoil around the piles consisted of medium and coarse sands with the density index ID>0.67. The pile heads were free. The points of support of the reference frame to which the sensors were fastened were located at the distance of 0.6 m from the side surface of the pile loaded laterally. In order to assure the independence of measurement, additional control (verifying) geodetic survey of the displacements of the piles subject to the load tests was carried out. The research conducted at Wroclaw University of Technology made it possible to collect and summarize the results of displacement measurements in course of static load testing of driven piles in a slope. Only selected case studies of cyclic loading in horizontal (lateral) pile load tests are presented in the paper.

Construction and verification of a unified p–y curve for laterally loaded piles

Estimation of the lateral pile load capacity is the key design procedure for structures where lateral loads are predominant, such as bridges, tall buildings and offshore platforms. In the process of laterally loaded pile design, the p–y curve method is the mainstream method and preferred by designers compared to the elastic continuum or finite element analysis. The traditional p–y curves are derived from some specific field tests and limited data, which do not reflect the overall conditions. In this study, a unified p–y curve based on the stress increment perspective was constructed by introducing Vesic cavity expansion theory and considering the actual stress state of the surrounding soils. The proposed p–y curve combines the contributions of the expansion-induced soil radial stress increment, vertical stress increment and lateral soil resistance caused by deep pile rotation. To validate the proposed method, case examples of lateral pile load tests in various soil conditions were prepared and used to compare the p–y curves from the test results and proposed methods. The p–y curves calculated from the proposed method show reasonable agreement with measured results and give a good prediction in large deformation analysis.

Impacts of Scour on Lateral Pile Behavior in the Marine Environment

Piles supporting marine structures are subjected to lateral loads due to berthing, mooring forces, waves and current forces. Scour around piles can have significant impact on the lateral loading capacity and hence affect the stability of marine structures. This paper presents the impact of scour on lateral loading of single piles and pile groups installed in coheshionless soils. Finite element modeling and Winkler model were used in the analyses. Different parameters were considered such as scour depth, magnitude of lateral load, pile group arrangement, pile spacing, pile slenderness ratio and pile batter angle. The results showed that global scour has greater impact on lateral pile capacity compared to local scour. Scour has greater impact on lateral loading of pile groups compared to its impact on single piles. Pile groups with side-by-side arrangement exposed to scour are more critical than single piles and piles groups with tandem arrangement due to the combined effect of scour and pile-soil-pile interaction. Some recommendations for scour protection are provided based on pile group arrangement, pile spacing and slenderness ratio

Three dimensional elasto‐plastic interface for embedded beam elements with interaction surface for the analysis of lateral loading of piles

SummaryThis paper presents a numerical formulation for a three dimensional elasto‐plastic interface, which can be coupled with an embedded beam element in order to model its non‐linear interaction with the surrounding solid medium. The formulation is herein implemented for lateral loading of piles but is able to represent soil‐pile interaction phenomena in a general manner for different types of loading conditions or ground movements. The interface is formulated in order to capture localized material plasticity in the soil surrounding the pile within the range of small to moderate lateral displacements. The interface is formulated following two different approaches: (i) in terms of beam degrees of freedoms; and (ii) considering the displacement field of the solid domain. Each of these alternatives has its own advantages and shortcomings, which are discussed in this paper. The paper presents a comparison of the results obtained by means of the present formulation and by other well‐established analysis methods and test results published in the literature. Copyright © 2016 John Wiley & Sons, Ltd.

Embedded beam element with interaction surface for lateral loading of piles

SummaryThis paper presents a numerical formulation of a three dimensional embedded beam element for the modeling of piles, which incorporates an explicit interaction surface between soil and pile. The formulation is herein implemented for lateral loading of piles but is able to represent soil–pile interaction phenomena in a general manner for different types of loading conditions or ground movements. The model assumes perfect adherence between beam and soil along the interaction surface. The paper presents a comparison of the results obtained by means of the present formulation and by means of a previously formulated embedded pile element without interaction surface, as well as reference semi‐analytical solutions and a fully 3D finite element (FE) model. It is seen that the proposed embedded element provides a better convergence behavior than a previously formulated embedded element and is able to reproduce key features of a full 3D FE model. Copyright © 2015 John Wiley & Sons, Ltd.

NUMERICAL MODELING TO EVALUATE PILE HEAD DEFLECTION UNDER THE LATERAL LOAD

The complex behavior of pile head deflection under the lateral load can be studied using various analytical methods and the softwares. Often the lateral pile load testing is carried out in the field to confirm the calculated lateral pile capacity. However, even with the use of sophisticated latest softwares, the accurate deflection of pile head cannot be estimated. Hence an attempt has been made in this paper to evaluate the pile head deflection using the field load-deflection data and the corresponding soil and pile properties. A preliminary mathematical model has been developed using a technique of dimensional analysis (DA) to evaluate pile head deflection under different pile diameters, different pile materials and varying soil conditions. The estimated pile head deflection using DA equation is compared with 14nos. of measured lateral pile load test results conducted at the site. It can be observed from this study that, the dimensional analysis can be used effectively to estimate the pile head deflection. More variables based on more field results can be introduced in the mathematical model to increase the accuracy in the estimation of pile head deflection.

Derivation of p-y Curves from Lateral Pile Load Test Instrument Data

Detailed analysis of a bored pile lateral load test is required to generate the family of non-linear lateral load–displacement curves known as “p-y” curves. Current methods of calculating these curves from test pile data may not make full use of all data (inclinometer, strain gage, head deflection) available. The method outlined below incorporates all available data in formulating a mathematical model of the pile behavior from which p-y curves may be derived.