Ground Motions and Structures - Earthquake Engineering for Structural Design - page 306

306 Earthquake Engineering for Structural Design

Layer
discontinuity

Figure 8.9 Pile foundations (after Bhattacharya et al, 2003)

Therefore, the buckling of piles must be considered.
The pile collapse mechanism is presented in Figure 8.10 (Bhattacharya, 2003). This
collapse mechanism seems to be very attractive for the dissipation of seismic energy.
But, as it was presented before, this form of structural collapse must be avoided, due to
the difficulties of consolidating the damaged piles.

8.3 STRUCTURALRESPONSE

8.3.1BehaviorofStructuresduringGroundMotions

The main effect of the ground motions on a structure is the dynamic nature of the
earthquake loading. As a consequence of time variability, the ground motions are
characterized by the time history of the three ground motion parameters at the level of
foundation, acceleration, velocity and displacement. For the structure subjected to such
ground motions, these actions will propagate through the structure as waves, causing
large oscillations (Fig. 8.11). Therefore, the structural response also varies with time,
involving dynamical movements. The structure performs a series of forced oscillations