Laterally loaded rigid piles with rotational constraints

Abstract

Elastic-plastic, closed-form solutions were developed recently by the author, to capture the nonlinear response of laterally loaded rigid piles. Presented in compact form, the solutions are convenient to use, and sufficiently accurate despite using only two input parameters of the net limiting force per unit length pu along the pile, and a subgrade modulus k. Nevertheless, piles may be subjected to limited cap-restraints or loading below ground surface, which alter the response remarkably.This paper provides explicit expressions for estimating loading capacity of anchored piles and develops new solutions for lateral piles with cap-rotation by stipulating a constant pu or a linear increasing pu (Gibson pu) with depth. Lateral loading capacity Ho (at the tip-yield state and yield at rotation point state) and maximum bending moment Mm (at the tip-yield state) are presented against loading locations, and in form of the lateral capacity Ho-. Mo (applied moment) locus. The capacity is consistent with available solutions for anchored piles, and caissons with either pu profile, allowing a united approach from lateral piles to anchored piles. The new solutions are also presented in charts to highlight the impact of rotational stiffness of pile-cap on nonlinear response, offering a united approach for free-head piles through fixed-head piles.Several advantages of the solutions are identified against the prevalent p-. y curve based approach. To estimate the key parameter pu, values of the resistance factor Np (=ratio of pile-soil limiting resistance over the undrained shear strength su) are deduced using the current expressions against available normalised pile capacity involving the impact of gapping (between pile and soil), pile movement mode, pile slenderness ratio, inclined loading angle (anchored piles) and batter angles (lateral piles). The Np is characterised by: (i) An increase from 5.6-8.6 to 10.14-11.6, as gapping is eliminated around lateral piles and caissons, and from 1.0-6.1 to 2.8-9.8, as translation is converted into rotation mode of footings. (ii) Similar variations with slenderness ratio between anchors and caissons (without gapping), and among anchors, caissons and pipelines (with gapping). And (iii) A reduction with loading angles (anchors) resembling that with batter angles (piles).

Reliability Based Analysis and Optimum Design of Laterally Loaded Piles

“…Evaluate of the lateral load capacity is an important component in the analysis and design of pile foundations subjected to lateral loadings and soil movements. Elastic-plastic solutions for free head and fixed head single laterally loaded piles were developed recently [6,7]. They are subsequently extended to cater for response of pile groups by incorporating p-multipliers.…”

Analysis of piles subjected to lateral soil movements using a three‐dimensional displacement approach

“…Guo presented the impact of loading angle between the horizon and loading direction on the pile behavior. The inclined soil movement can be divided into the vertical and lateral components.…”

“…Chow and Chen and Poulos presented theoretical procedures for analyzing the lateral response of pile groups subjected to soil movements. Recently, Guo has proposed new pile‐soil models that represent the elastic‐plastic response of circular piles subjected to soil movement and lateral loadings.…”

Nonlinear Response of Lateral Piles with Compatible Cap Stiffness and p-Multiplier

“…It may then be 111 calculated using axial stiffness and capacity of a single pile, with due account of the pile group 112 spacing (Mokwa and Duncan 2003 warranted between the piles. In fact the ratio becomes far greater than 4 once plastic deformation 122 is induced (Guo 2013b induced on a pile-head with translation only (FixH) pile; and the design pile-head deflection w g 128 be 1.25 times the w g FixH gained using the FixH solutions (JGJ 1994). The ratios will be used later 129 to determine the stiffness k r .…”