Micropiles are reinforced grouted piles that have
small diameters commonly not higher than 30 cm. They are
widely used for slope stabilization, controlling structural
settlement, and in some cases, as retaining structures. Also, they
are used for resisting dynamic uplift loads, seismic retrofit mainly
in restrictive and low headroom areas, and retrofitting of
historical monuments. The main goal of this research is to
develop a finite element model that can capture the different
aspects of seismic behavior of multi-story structure supported
with deep foundation via using of micropiles. Also, a main target
for the executing numerical modelling is to show the influence of
the surrounding soil on this system and vice versa. Firstly, a
representative two-dimensional finite element model is conducted
to represent the soil-structure interaction system under seismic
excitation supported with proper boundary conditions in PLAXIS
2D V20 for dynamic analysis based on previous recommendations
considering the nonlinear soil behavior. The behavior of
micropiles is studied and verified using previous results. Based on
these models, the effect of lateral dynamic loads on the response
of a structure with different foundation types is investigated. Also,
a wide range of parametric studies, considering structure
properties, earthquake magnitude, micropile diameter, micropile
length, and the number of micropiles, have been carried out in
order to investigate the actual interaction between soil, substructure, and superstructures. The study results showed that the
seismic response of the structure is highly affected by the
properties of the sub-surface soil layer. Consequently and
similarly, analysis results established that underpinning using
micropiles is an efficient technique for controlling the seismic
response of existing structures.
Seismic response of multi-story structure with multiple tuned mass friction dampers