Ground Motions and Structures - Earthquake Engineering for Structural Design - page 313

Ground Motions and Structures 313

Figure 8.15 Continuous shear-beam model (Gioncu and Mazzolani, 2002)

8.3.2 CapacityTriad:Stiffness,Strength, Ductility,plusRobustness

In order to evaluate the response of structures during earthquakes, the best method is
to use a dynamic analysis for the time history representation of seismic loading,
obtained from a recorded ground motions (ASCE, 2005). However, this methodology
has the disadvantage to consider just the structural behavior for a given level of
seismic loading, without the representation of the structure collapse. In this situation,
the nonlinear static procedure is the best way to evaluate the structural response. This
procedure is intended to provide a simplified approach for directly determining the
nonlinear response behavior of a structure at different levels of lateral loads, ranging
from the initial elastic response through the development of a failure mechanism and
the initiation of collapse (Fig. 8.17). The role played in the seismic analysis by the
triad of capacities (stiffness, strength and ductility) plus robustness is illustrated in the
following.