Received: 20 September 2017 Revised: 10 September 2018 Accepted: 12 September 2018 DOI: 10.1002/nag.2863 RESEARCH ARTICLE Analysis of lateral loading of pile groups using embedded beam elements with interaction surface Diego F. Turello 1,4 Federico Pinto 1,2 Pablo J. Sánchez 3,4 1 Universidad Nacional de Córdoba - FCEFyN - CONICET, Av. Velez Sarsfield 1611, CP:5000, Córdoba, Argentina 2 DIT UNC-CONICET, Av. Velez Sarsfield 1611, CP:5000, Córdoba, Argentina 3 CIMEC UNL-CONICET, RN N ◦ 168, Km 0, Paraje El Pozo, CP:3000, Santa Fe, Argentina 4 GIMNI-UTN-FRSF, Lavaise 610, CP:3000, Santa Fe, Argentina Correspondence Federico Pinto, Universidad Nacional de Córdoba - FCEFyN-IDIT UNC-CONICET, Casilla de Correo 916, Córdoba, Argentina. Email: fpinto@unc.edu.ar Funding information SECyT UNC, Grant/Award Number: 05/M282; CONICET, Grant/Award Number: PIP 2013-2015 631; European Unions Seventh Framework Programme (FP/2007-2013)/ERC, Grant/Award Number: 320815 Summary The numerical simulation of soil-pile interaction problems, by means of full 3D finite element models, involves a large number of degrees of freedom (DOF) and difficulties during the mesh generation process. In order to reduce the unknowns and simplify and properly analyze such class of geotechnical prob- lems, the so-called embedded beam elements (EBE) have recently been devel- oped. In a preceding contribution of the authors, an improved EBE formulation, which brings into play the soil-pile interaction surface, was proposed with the aim to localize material plasticity in the soil surrounding the pile. This embed- ded beam model couples two different finite elements, each described by distinct kinematics (ie, solid and beam). The coupling is incorporated in the formulation by means of kinematical constrains established over the solid and beam dis- placement fields on the interaction surface. One of the main advantages of the embedded elements is that the addition of beams structural members immersed within the 3D soil model does not represent a constraint for the solid mesh, which can be adopted independently from the beam mesh. In this paper, the lat- eral loading of pile groups is studied by means of the proposed EBE approach with elasto-plastic interfaces. In order to represent a rigid cap, a master node and a special set of kinematical restrictions are incorporated into the formulation. The paper presents results obtained by means of the present formulation com- pared against other well-established analysis methods and test results published in the literature, for both elastic and elasto-plastic cases. KEYWORDS elasto-plastic interface, embedded beams elements, lateral loading, pile groups, soil-pile interaction 1 INTRODUCTION The mechanical response of lateral loading of piles, and specially pile groups, depends on several factors, such as soil-structure interaction phenomenon that develops at the interface, the relative stiffness between pile and soil, and the range and type of loadings. In the case of pile groups, pile-soil-pile interaction effects have to particularly be accounted for in the analysis. According to Randolph, 1 this phenomenology strongly depends upon the pile spacing within the cap, which is the distance between pile centers. In the case of lateral loading of pile groups, the stiffness imposed by the cap in the pile heads introduces axial effects that need to be accounted for, as the cap couples both deformation modes (ie, lateral and axial). Int J Numer Anal Methods Geomech. 2018;1–21. wileyonlinelibrary.com/journal/nag © 2018 John Wiley & Sons, Ltd. 1