Prabhakar J. Pise

Abstract: Quantitative estimates of the various soil-pile parameters on lateral pile head displacement, rotation and moment coefficients are presented in dimensionless terms through graphs. The results provide guidelines to predict the lateral response of free-head piles. The illustrative example highlights the utility of the results. These results can also be used to predict the responses of partially restrained head piles.

Abstract: The Paper presents the results of a systematic parametric investigation of the static and dynamic response of single free-head piles embedded in a soil stratum, the modulus of which increases linearly with depth. The study is conducted by means of a dynamic finite-element formulation which accounts for the three-dimensionality of soil deformation while properly reproducing the radiation damping characteristics of the system. The soil is modelled as a linear hysteretic continuum and the excitation consists of a sinusoidally time-varying horizontal force or moment, applied at the pile head. Comprehensive plots of the results are presented in non-dimensional form, for a wide range of the most significant dimensionless groups of problem parameters. For the response of flexible piles, in particular, simple algebraic expressions are developed in terms of the ratio E,/E,, of the pile and soil moduli. These expressions, being valid for several values of Poisson’s ratios of the soil, compare favourably with results from previous studies and are expected to be useful in practical design calculations.

Abstract: An extensive program of laboratory model tests was undertaken to study the effect of slope on p-y curves due to surcharge load in dry sand. The paper concerns the method developed in a series of laboratory model tests to experimentally determine p-y curves. Bending moment curves are differentiated by using curve fitting method of cubic polynomial function. The study includes effect of slope angle and relative density on bending moment, lateral soil resistance, lateral deflection and non-dimensional p-y curves. The non-dimensional p-y curves for piles on sloping ground under surcharge load are developed modifying API RP 2A (2000) method by including a Reduction Factor (R) using the experimental results.

Abstract: Eighteen lateral loading tests were conducted on large-scale steel piles to establish the lateral behaviour of tapered piles in cohesionless soil. Three piles 1.52 m in length with different taper ...

Abstract: Piles have been extensively used for supporting axial loads and lateral loads for variety of structures including high rise buildings, transmission towers, power stations, offshore structures and highway and railway structures. Many transmission towers, high rise buildings and highway and railway bridges are constructed near steep slopes which are supported by pile foundations. These structures may be subjected to large lateral loads such as strong winds or earthquakes. When piles are constructed in sloping ground, the behaviour of piles under lateral load is different from piles in horizontal ground. The present investigation is to study the behaviour of piles on sloping ground under lateral loads. A series of laboratory model test had been carried out on the instrumented pile on horizontal ground, 1V: 2H slope and 1V: 1.5H slope with the relative density of sand at 30%, 45% and 70% and varying embedment length to diameter ratio of 25, 30, and 35. From the experimental results, the behaviour of t...

Abstract: A detailed laboratory experimental model tests was undertaken to study the effect of slope on laterally load pile capacity and p–y curves. The paper concerns the method developed in a series of laboratory model tests (27 lateral load tests) to experimentally determine p–y curves. The study was carried out on horizontal ground and two different types of slope such as, 1 Vertical to 2 Horizontal (1V:2H) and 1 Vertical to 1.5 Horizontal (1V:1.5H) with different relative density of 30, 45 and 70 % and three different pile embedment lengths [length to diameter ratios (L/D) of 25, 30 and 35]. The study includes the effect of ground slope, relative density and embedment length on lateral load capacity, bending moment, lateral soil resistance, lateral deflection and p–y curves. From the study it is concluded that the increase in pile-soil relative stiffness increases the lateral resistance against the lateral load and hence the depth of fixity reduces for increase in relative density. It is also found that the soil resistance increases with increase in the depth of the soil, relative density of the soil and the embedment length of the pile whereas the soil resistance decreases with increase in the slope of the ground surface.