Vertical loads effect on the lateral pile group resistance in sand

Abstract

Vertical loads effect on the lateral response of a 3×5 pile group embedded in sand is studied through a two-dimensional finite element analysis. The soil-pile interaction in three-dimensional type is idealized in the two-dimensional analysis using soil-pile interaction springs with a hysteretic nonlinear load displacement relationship. Vertical loads inducing a vertical pile head displacement of 0.1-pile diameter increase the lateral resistance of the single pile at a 60 mm lateral deflection by 8%. Vertical loads inducing the same vertical displacement applied to a pile group spaced at 3.92-pile diameter increase the overall lateral resistance by 9%. The effect on individual piles, however, depends on the pile position. The vertical load decreases the lateral resistance of the leading pile (pile 1) by 10% and increases the lateral resistances of piles 2, 3, 4, and 5 by 9%, 14%, 17%, and 35%, respectively. Vertical loads applied to the pile group increase the confining pressures in the sand deposit confined by the piles but the rate of increase in those outside the group is relatively small, resulting in the difference in a balance of lateral soil pressures acting at the back of and in front of the individual pile.

Kinematic and inertial forces in pile foundations under seismic loading

“…of 10 m. The fixed-base natural frequency of the structure is denoted by f str.fixed and is given by ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi k str: =m str: p =2p. Moment curvature relationships of the pile and the structural column are idealized with bilinear curves, whose parameters are obtained from standard sectional analysis given the material and sectional properties [35][36][37]. To investigate kinematic interaction, only the soil-pile subsystem (without the superstructure) was considered.…”

“…In addition to the conventional assumption of hyperbolic relationship assigned for each shear spring for monotonic initial loading, the model uses the extended Masing rule to reproduce more realistic hysteresis loop for cyclic loading [45][46][47]. The multi-shear mechanism soil model is now widely used in design practice, especially for designing geotechnical structures in port and harbors in Japan [34][35][36][37]. The core of the modeling is briefly introduced:…”

Lateral Response of a Single Pile under Combined Axial and Lateral Cyclic Loading in Sandy Soil

“…This would lead to an erroneous design, as pile foundations for several types of structures are subjected to simultaneous vertical and lateral loading. The separate consideration of the vertical and lateral loading therefore cannot be expected to account properly for the pile behavior [1][2][3][4]. The methods of analysis commonly used in predicting the response of a single pile are the elastic half space method, and the nonlinear subgrade reaction method.…”

Contribution to the design methodologies of piled raft foundations under combined loadings

“…analyses on single 27 piles and based on their results they reported an increase on the lateral load pile capacity in 28 sandy soils and a decrease in clayey soils as a result of the action of a vertical load. A 29 simplified numerical simulation of soil-pile interaction led Hussien et al (2012Hussien et al ( , 2014 to the 30 conclusion of a limited increase in the lateral capacity of free-head piles in sandy soil. 31…”