PSI - Issue 44

Devis Sonda et al. / Procedia Structural Integrity 44 (2023) 1188–1195 Devis Sonda et al. / Structural Integrity Procedia 00 (2022) 000 – 000

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Table 3. Different combinations of model parameters and seismic actions analyzed. Analysis ID Model ID Device F eq [kN] Seismic site Importance class

PGA [g]

A-SC20-CA A-SC30-CA B-SC20-CA A-SC30-FA C-SC20-FA C-SC30-FA C-SC50-FA

A A B A C C C

20 30 20 30 20 30 50

Carpi Carpi Carpi

1.5 1.5 1.5 1.0 1.0 1.0 1.0

0.257 0.257 0.257 0.287 0.287 0.287 0.287

Faenza Faenza Faenza Faenza

In the following figures some examples of results of time-history analyses are shown with curves representing values of shear and moment at column base, varying scale factor of seismic input. A first comparison (Figure 4) between the model with CWST dissipative fuse connections (DEV) and hinged connections (HIN) has been made using mean values of the whole set of 7 acceleration time histories. Then, a second comparison (Figure 5) between the model with dissipative fuse connections (DEV) and hinged connections (HIN), has been made using mean values only of the number (N) of acceleration time histories activating the dissipative fuse devices. A blue dot in the curves indicates the first scale factor value for which the device reaches its maximum plastic deformation, ending its dissipative capability, for at least 1 time history.

a

b

c

Fig. 4. A-SC30-FA mean values of 7 TH: column base (a) shear and (b) moment; (c) reduction of values compared to hinged connections.

a

b

c

Fig. 5. A-SC20-CA mean values of N TH: column base (a) shear and (b) moment; (c) reduction of values compared to hinged connections.

In previous figures, it is possible to observe a significant reduction of maximum values due to seismic action (shear and moment) at column base. Curves in Fig. 4c and 5c represent the percentage of reduction of effect of actions at different scale factors applied to the seismic input. The reduction of seismic effects is more significant for the strongest seismic input (Faenza seismic site), that activates the dissipative fuse devices for all the 7 TH. The different analyzed models highlight that, for medium-low seismic intensity, the dissipative fuse devices with lower F eq are more effective.