## 3 Seismic Behavior of Micropiles
### Behavior of MPs in Association with Seismic Dampers
The results showed that the differences between the two directions (length vs. width of the isolator) were not that important; however, the number of lead cores played a significant role in increasing damping value [29]. Thus, increasing the damping value by using a method different than interfering to the base isolator structure, as using MPs, might be an interesting idea. MPs can also provide a stiff base, which is usually recommended for base isolators [8]; also, such a combined solution can be very useful for retrofitting existing structures and especially historical ones; as modifying the superstructure is not allowed in such cases (historical structures) or it can be difficult; a combination of MPs and base isolators can provide the solution, as MPs help in increasing the foundation capacity, soil stabilization, and potential benefit in both kinematic and inertial interactions, while base isolators decouple the superstructure. Finally, the structure is retrofitted from geotechnical and seismic points of view, also by using MPs with the base isolators, the necessity of using large diameter base isolators might be reduced, depending on the way that MPs can help the base isolators. One example of seismic retrofitting with base isolators is St. [PERSON] church in Romania, where base isolators were installed under an historical masonry church [30]. Additionally, this was suggested and studied numerically by [PERSON] [31], who confirmed the suitability of base isolators in such cases, without intervention to the structural system  
To summarize, combining MPs with seismic dampers may positively influence the double enhancement of seismic dampers; these enhancements provide decoupling and increase damping value. Seismic dampers can do both, or mainly decoupling (for base isolators); here, MPs can either help in increasing damping value, which develops these basic base isolators from only a decoupling solution into a decoupling + increasing damping value solution. This also means that they can be used to optimize the base isolators, after taking into consideration the increase in damping value that they potentially provide. Alternatively, they can influence the decoupling phenomenon itself, indirectly by influencing the input motion, which may also lead to an optimization in the base isolator size [8; 22; 27]. This need to be further studied in detail to understand the influence of MPs on these two aspects. To better illustrate the idea of combining MPs with seismic dampers, the following figures are presented, starting with Figures 8-10, which present some typical details for base isolator attachment [20; 32; 33], and then Figures 11-13, which also present some typical details for MP connections to a structure (new or existing) [1]; and finally, Figures 14-16, which present new proposed details for combining MPs with seismic dampers; these three proposed details can be used for new structures as well as for existing structures. These are details proposed by the authors and they need extensive research in order to know their behavior and whether it is actually beneficial or efficient for seismic resilience applications. For achieving this, the authors start with the validation of the proposed connection from a structural point of view, completion of the understanding of the seismic behavior of MPs and MPed structures with the notes drawn by this paper, and continue with experimental tests and suitable numerical tests for these models. Figure 11: MP connection to a new structure (new reinforced concrete footing)—typical detail (after [1]). Figure 12: MP connection to a new/existing structure (new/existing reinforced concrete footing)—typical detail (after [1]). Figure 10: Base isolator system attachment to steel superstructure and concrete substructure—typical detail (after [20; 32; 23]). Figure 13: MP connection to a new/existing steel base frame—typical detail (after [1]). Figure 16: New proposed detail for combing MPs with BIS (new/existing steel base frame).