PSI - Issue 78

Emanuele Brunesi et al. / Procedia Structural Integrity 78 (2026) 161–168

165

3. Results of laboratory testing As discussed above, three full-scale building tests were undertaken, and this Section aims at providing a brief and concise overview of obtained results and observed performance/damage modes, partly because of page/space limits. In light of this, Figure 6 highlights how the connections between the different precast elements significantly affect the response of this type of structural systems, thus driving its hysteretic response and overall seismic capacity. More in detail, Figure 6 shows a clear example of the extensive damage undergone by one of the four three-way connections between the ground-floor stability wall and the corresponding transverse walls. The connectors embedded in the niche of the lateral walls were pulled and bent permanently (towards the opposite side) by the counterpart anchors installed into the sockets of the stability wall, owing to shear transfer mechanisms in the precast wall-elements of this portion of the structure. It is particularly noteworthy that also the latter connectors (i.e. the ones embedded in the sockets of the stability wall) were abruptly bent upwards, which caused the hook at their ends to become straight and the three wall panels to get completely disconnected. As a result of the above, a 38% strength reduction was observed, which implies that the specimen was unable to withstand any further load of relevance, as confirmed by the gap opening between the transverse and stability walls. A very similar outcome was obtained by pseudo-static cyclic testing (Figure 7), although the accumulation of displacements following connection failure was less pronounced simply because the test was brought to a halt much earlier, soon after the steel connectors got heavily damaged and disconnected.

Fig. 6. Hysteretic response of the dynamically tested precast specimen and outwardly-upwardly bent steel hooks in a wall connection.

Fig. 7. Hysteretic response of the pseudo-statically tested precast specimen and deformed shape corresponding to the last testing stage.

The above damage mechanisms can be gathered from both deformed shape of the full-scale building specimen at the last stage of pseudo-static cyclic testing as well as hysteretic base shear versus top displacement response curves that, interestingly, show damage and subsequent reduction of capacity owing to issues of connection failure for a very similar displacement level. At the same time, it is worth mentioning that differences in base shear are ascribed partly to a different force distribution along the floors (i.e. assumed to be triangular during pseudo-static cyclic testing) and mostly to the fact that the interface fabric felt layer initially placed between the first-storey slab panels and the ground-