Micropiles systems present significant advantages for the construction in seismic areas, mainly flexibility, ductility and capacity to withstand extension forces. Micropiles can be used as foundation support for new structures as well as a new solution for seismic retrofitting of structures, which have suffered seismic damage. This thesis presents a study of static and dynamic behaviour of single micropile and dynamic behaviour of micropile groups against lateral loading. Analyses were carried out using 3-D nonlinear finite element program, ABAQUS. The soil behavior was assumed as elastoplastic with modified Drucker-Prager/Cap plasticity model and Rayliegh damping. In order to study of static behaviour of single micropile, the effect of parameters such as sliding and gapping between soil and micropile, nonlinearity of soil and soil modulus of elasticity is investigated. In studying dynamic behaviour of single micropile, the effects of mass and frequency of superstructure are considered. Dynamic behaviour of group of micropiles is studied taking into account effects of spacing of micropiles, number of micropiles in group, position of micropiles in group, inclination of micropiles, connection between cap and micropiles, embeddement of tip of micropiles in stiff substratum and depth based-increasing soil stiffness.
