Experimental Methods in Earthquake Engineering - Dynamic Behavior of Concrete and Seismic Engineering - page 178

Figure 5.3. Typical structures tested at ELSA
As the deck has been modeled, the piers can be put side to side, which allows a
reduced space. In addition to horizontal jacks, vertical jacks can be seen at the front
of the piers, where they apply the vertical loading due to the weight of the deck. On
the right in Figure 5.3 is a real size 4-storey frame in a configuration including a
filled in wall which was tested in the same period.
5.3. Continuous pseudo-dynamic method
5.3.1. Continuous method principle
The conventional PSD method requires considerable implementation time. The
structure is stopped when it reaches the specified displacement, so the reaction force
can be measured. The break, which can be about several seconds long, harms the
regularity of the loading and causes interfering relaxation phenomena inside the
structure. With the continuous PSD method [MAG 98], [MAG 00], the movement of
the jacks is not deliberately stopped; therefore, it can follow the specified
displacement quite accurately, because it no longer includes any discontinuity. The
load can now be measured for each sampling period of the control system and the
motion equations are immediately integrated, at the same frequency, to continuously
provide a new displacement target. To achieve this goal, it has been necessary to