PSI - Issue 44

Elisabetta Maria Ruggeri et al. / Procedia Structural Integrity 44 (2023) 464–471 E. Ruggeri, G. D’Arenzo, D. Li Cavoli, R. Cottonaro, M. Fossetti/Structural Integrity Procedia 00 (2022) 000–000

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LVDT was used to measure the uplift of the perpendicular wall in correspondence of the hold-down. The horizontal displacement on the top of the wall was obtained by subtracting the horizontal displacement of the HEB 220 from the top horizontal displacement of the shear wall. A steel structure system was used to avoid the out-of-plane movements of the wall.

Fig. 3. Test set-up of the two configurations: (a) SW, (b) SW+PW.

Monotonic tests were performed in displacement control with the imposed displacement increasing at a constant rate of 0.15 mm/sec, see Figure 4 (a) (EN594 2011). The standard procedure prescribed by EN 12512 (EN12512 2005) was followed in the cyclic tests, see Figure 4 (b). All tests were performed without applying any vertical load in order to study the lateral behavior of the system using fewer parameters. Mechanical properties of monotonically and cyclically tested shear walls were evaluated according to EN 12512 (EN12512 2005). Mechanical parameters evaluated from the load-displacement curves of monotonic tests and from the backbone curves of the cyclic tests are the yielding load F y , the yielding displacement V y , the maximum load F max , the maximum displacement V max , the ultimate load F ult , the ultimate displacement V ult , the ductility D and the elastic stiffness K el , which was calculated as the slope between 10% and 40% of the maximum load. Mechanical parameters evaluated from cyclic hysteresis loops of the cyclically tested walls are the dissipated energy E d , the Equivalent Viscou s Damping υ eq , and the impairment of strength between first and third cycle Δ F 1-3 . Cyclic tests were conducted considering a rate between 0.5 and 2.5 mm/sec, depending on the displacement level. All the mechanical parameters obtained from the tests are provided in the next section.

Fig. 4. Loading protocol for (a) monotonic and (b) cyclic tests.

4. Results and discussion In this section experimental results are presented. As expected, the CLT wall panels behaved almost as rigid bodies during the testing. Most of the panel deflections occurred as a result of the deformation in the joints connecting the walls to the steel foundation. Figure 5 (a) and (b) show the failure mechanisms of the SW configuration and SW+PW configuration, respectively. The shear wall systems moved with a predominant rocking mechanism and reached the failure in the hold-downs, due to the relatively low aspect ratio of the walls.