The Response of Driven Single Piles Subjected to Combined Loads (original) (raw)
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BEHAVIOR OF LATERALLY LOADED PILES IN COHESIVE SOILS
Pile foundations are often required to resist lateral loading. Lateral loads come from a variety of sources including wind, earthquakes, waves, and ship impacts. So, it is important to know the lateral load resistance capacity of pile foundation. This requires estimation of ultimate loads based on which safe working loads will be assessed and also estimation of pile deflections to ensure that serviceability aspects are accounted in the design Several methods are available for predicting the ultimate lateral resistance to piles in clay soil. However, these methods often produce significantly different ultimate resistance values. This makes it difficult for practicing engineers to effectively select the appropriate method when designing laterally loaded piles in clay soil. In this paper, lateral load behavior of single piles in clay soil was studied, for different L/D ratio by changing the diameter and length of pile. The analysis was carried out by considering free head pile. The influence of soil type, effect of pile length and pile diameter on the pile response was observed and the results obtained by IS2911Part1 (sec2) were compared with the Broms method. Also deflection and lateral load were calculated for a typical pile for various L/D ratio and their results were presented
Dynamic response of laterally loaded piles in clay
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 2006
The behaviour of single piles under lateral dynamic loading is critical, and has been an important field of research since the 1950s. Many analytical or semi-analytical linear and non-linear models are available to estimate the dynamic lateral stiffness, but it is essential to determine the dynamic characteristics of the soil–pile system through full-scale lateral dynamic pile load tests for important structures and for validation of existing models. This paper presents the results of field lateral dynamic load tests conducted on 33 piles of varying types–driven precast concrete, driven cast-in-situ concrete and bored cast-in-situ concrete–at different petrochemical complexes in India. The results indicate that driven precast concrete piles have stiffnesses that are four to five times higher than those of driven cast in situ piles. The lateral stiffness was also estimated using the computer program PILAY for all piles and compared with the stiffness determined from the field tests. ...
Lateral Pile Response Subjected to Different Combination of Loadings
Journal of Engineering Science and Technology Review
Pile-soil interaction has been a subject of interest to many earlier researchers. However, not much work has been done on the effects of structural response of single piles subjected to different combination of axial and lateral loads and hence the respective pile-soil interaction. The main objectives of this paper are to assess the influence of axial load intensities on the lateral single isolated pile response in various pile slenderness ratios. Three-dimensional finite element approach was used to simulate the whole geotechnical system. The finite element included linear elastic model to represent the pile, Mohr-Coulomb to model surrounded soil and 16-nodes interface element to simulate the pile-soil interface. It was found that the lateral deflection is increased with increased the axial load in case of cohesionless soils. While, in case of cohesive soil, reduction in lateral pile displacement is occurred when low axial load is applied (i.e. V less than 4H) and increased when axial load level (i.e. V more than 6H) has been increased.
Modelling and Assessment of a Single Pile Subjected to Lateral Load
Studia Geotechnica et Mechanica, 2018
A three-dimensional finite element technique was used to analyse single pile lateral response subjected to pure lateral load. The main objective of this study is to assess the influence of the pile slenderness ratio on the lateral behaviour of single pile. The lateral single pile response in this assessment considered both lateral pile displacement and lateral soil resistance. As a result, modified p-y curves for lateral single pile response were improved when taking into account the influence lateral load magnitudes, pile cross sectional shape and flexural rigidity of the pile. The finite element method includes linear elastic, Mohr-Coulomb and 16-nodes interface models to represent the pile behaviour, soil performance and interface element, respectively. It can be concluded that the lateral pile deformation and lateral soil resistance because of the lateral load are always influenced by lateral load intensity and soil type as well as a pile slenderness ratio (L/D). The pile under ...
Numerical Evaluation of Pile Response Under Combined Lateral and Axial Loading
Geotechnical and Geological Engineering
Piled foundations are frequently subjected to simultaneous axial and lateral loadings. However, the interaction effects of the one loading on the other are, in most cases, disregarded for the sake of simplicity. With the aim of evaluating this effect, a detailed research work on the response of a single pile under simultaneous application of axial and lateral loading was carried out. A qualitative assessment of the effect was initially attempted and the effect was afterwards quantified, based on the results of an intensive three-dimensional parametric numerical analysis. The influence arising from pile head fixity and the second order phenomenon was examined, while the post-peak behaviour was also considered using a strain hardening/softening constitutive law. Interesting conclusions have been drawn, providing a qualitative and quantitative evaluation of the effect on clayey and sandy soils. It was also found that no loading interaction effect is developed, when ultimate limit state is applied for a piled foundation design. On the contrary, when the serviceability limit state is applied and if the pile capacity in both lateral and axial loading is simultaneously reached, a reduction in the pile axial capacity is observed in the case of clayey soils. On the contrary, in the case of sandy soils the action of a lateral load is leading to an increase of pile axial capacity.
Observed and Computed Response of Piles Under Dynamic Loads
This paper presents a comparison of observed computed response of a single pile. Full scale dynamic pile load tests were conducted on a 450 mm diameter reinforced concrete pile driven 17m in a soil profile of uniform silty sand. Horizontal deflection of the pile at the mud line was measured by applying predetermined horizontal load increments during the static test. The dynamic load tests were conducted to determine the amplitude frequency response of the pile subjected to vertical and horizontal vibrations. The natural frequency of free vibrations in the horizontal direction was also measured. The soil properties were determined by conducting in-situ and laboratory tests. The response of the single piles was calculated and compared with the observed response.
Continuum-based analyses for laterally loaded piles with rectangular and circular cross sections are presented using solutions that can be obtained quickly without requiring any elaborate inputs for the geometry and numerical mesh. The analysis is developed by solving the differential equations governing the displacements of the pile-soil system derived using the variational principles of mechanics. Parametric studies are performed to investigate the influence of the pile cross-sectional shape, soil layering, pile slenderness ratio, and pile-soil modulus ratio on the response of laterally loaded piles in heterogeneous soil in which the soil shear modulus varies continuously or discretely with depth. The results show that piles with the same second moment of inertia have similar lateral-load response. The lateral responses of piles in two-layer systems were mainly affected by the thickness and stiffness of the top soil layer. Soil layering also influences the lateral response of piles in three-layer soil deposits consisting of two thin layers overlying the third layer. Algebraic equations for estimating the pile-head deflection and maximum bending moment are proposed that can be readily used in design. A user-friendly spreadsheet program is developed as a tool to perform calculations of pile response using the analysis. Numerical examples demonstrating the use of the analysis are provided.
RESPONSE OF LATERALLY LOADED SINGLE PILE IN SANDY SOIL
Pile foundations are often required to resist lateral loading. Lateral loads come from a variety of sources including wind, earthquakes, waves, and ship impacts. The lateral capacity of a pile is usually much smaller than the axial capacity and as a result groups of piles are often installed to increase the lateral capacity of the entire foundation system. When vertical or plumb pile groups do not provide sufficient lateral resistance the piles can be battered in order to mobilize some of the higher axial capacity to resist the lateral load. Several methods are available for predicting the ultimate lateral resistance to piles in sandy soil. However, these methods often produce significantly different ultimate resistance values. This makes it difficult for practicing engineers to effectively select the appropriate method when designing laterally loaded piles in sandy soil. In this paper, lateral load behavior of single piles in sandy soil was studied, for different L/D ratio by changing the diameter and length of pile. The analysis was carried out considering long free-head pile. The influence of soil type, effect of pile length and pile diameter on the pile response was observed and the results obtained by IS2911Part1 (sec2) and Matlock & Reese were presented.
On the influence of vertical loads on the lateral response of pile foundation
Computers and Geotechnics, 2014
The influence of vertical loads on the lateral response of group piles installed in sandy soil and connected together by a concrete cap is studied through finite elements analyses. The analyses focus on the five piles in the middle row of 3 Â 5 pile groups. The vertical load is applied by enforcing a vertical displacement equivalent to 2% of the pile diameter through the pile cap prior to the application of the lateral loads. The results have shown that the lateral resistance of the leading pile (pile 1) does not appear to vary considerably with the vertical load. However, the vertical load leads to 23%, 36%, 64%, and 82% increase in the lateral resistance of piles 2-5, respectively. The increase in the lateral pressures in the sand deposit is the major driving factor to contribute the change in the lateral resistance of piles, depending on the position of the pile in the group. The distribution of lateral loads among piles in the group tends to be more uniform when vertical loads were considered leading to a more economical pile foundation design.
Effect of the Non-Linear Behavior of Pile Material on the Response of Laterally Loaded Piles
2001
The main purpose of this study is to assess the lateral response of piles/shafts and the p-y curves for different soil-pile combinations while introducing the effect of the moment-curvature (M-0) relationship of the pile into the soil-pile interaction. Therefore, the equilibrium among soil reaction, pile deflection pattern, pile-head load, and flexural stiffness distribution should be satisfied at any level of loading. The influence of the nonlinear behavior of the pile/drilled shaft material on the nature of the associated p-y curve is presented through strain wedge (SW) model analysis. The SW model allows the assessment of the (soil-pile) modulus of subgrade reaction (i.e. the p-y curve) based on soil and pile properties which includes the pile bending stiffness. Therefore, the assessed modulus of subgrade reaction will be affected by changes in the bending stiffness of the pile or drilled shaft at any pile cross section (via the M-Q relationship). The reduction in pile bending stiffness will affect the pile-head stiffness under varying static or dynamic loading.