PSI - Issue 78

Riccardo Raimondo Milanesi et al. / Procedia Structural Integrity 78 (2026) 1374–1381

1376

exectued boundary condition to study the influence of such a detail. The masonry mortar bed-joint had a thickness of approximately 1 cm, and the mortar head-joints had been barely filled to resemble the Italian construction techniques of the 1960s-1980s. The specimens can gather into batches with the difference reported in Table 1. Batch 1 can be defined as the reference batch for a 13 cm thick infill, batch 2 studied the influence of poorly executed top boundary condition, batch 3 is focused on the influence of openings, with (3b) and without (3a) sprandler, batch 4 is referred to 9 cm thick masonry panels. Table 1. Summary of the detail of each specimen and tests performed. Specimen Top Boundary condition Thickness (masonry + plaster) Lateral edges Opening In Plane test Max IP drift* Out-of Plane test Max OOP PFA* Batch (year)

T1 T2 T3 T4 T5 T6 T7 T8 T9

Filled Filled Filled Filled Filled

12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled 12+1=13 cm Filled

No No No No No No No

Yes Yes Yes No No Yes Yes No No Yes Yes No Yes Yes No Yes Yes No No

1.00% No 0.30% Yes 0.65% Yes

---

1 (2021)

2.50g 1.50g 2.75g 1.00g 1.25g 1.75g 0.50g 1.50g 2.00g 1.50g 2.00g 0.20g 1.80g 0.50g --- --- --- ---

--- ---

Yes Yes

12+1=13 cm Gap (about 2 cm) No

Poorly executed Poorly executed Poorly executed Poorly executed

1.50% No 0.65% Yes

2 (2022)

--- ---

Yes Yes

12+1=13 cm Gap (about 2 cm) No

T10 T11 T12 T13 T14 T15 T16 T17 T18 T19

Yes Yes Yes Yes Yes Yes No No No

Filled Filled Filled Filled Filled Filled Filled Filled Filled Filled

1.00% No 0.50% Yes 1.00% No 0.50% Yes 1.25% No 0.65% Yes --- Yes --- Yes

3° (2023) 3b (2023) 4 (2024)

8+1=9 cm 8+1=9 cm 8+1=9 cm 8+1=9 cm

Filled Filled Filled

--- ---

Yes Yes

Gap (about 2 cm) No

* Nominal values The testing procedure within every batch consisted of one specimen tested only in‑plane up to collapse, one panel tested only out‑of‑plane up to collapse, and the remaining infill (two infills in Batch 1 only) tested in‑plane up to a defined damage level a nd, subsequently, out‑of‑plane until collapse. When the batches include a specimen restrained on only two edges (top and bottom), the infill is subjected only to out‑of‑plane testing. Table 1 summarizes the nominal in‑plane drift and maximum out‑of‑plane nominal PFA attained for each specimen. A comprehensive characterization of the masonry infill materials was performed for each batch. The compressive strength of the clay units was measured under both vertical loading (perpendicular to the holes, f b ) and lateral loading (parallel to the holes, f b ′) in accordance with EN 772 - 1 (CEN, 2015), while mortar flexural strength (f fl ) and compressive strength (f m ) were determined following EN 1015 - 11 (CEN, 2019). Masonry compressive tests were carried out on 77 × 77 cm wallets (three units by three units) according to EN 1052 - 1 (CEN, 2001) in both the vertical (f vert ) and lateral (f lat ) directions. The elastic moduli in these directions (E v , E lat ) were evaluated at a stress level equal to one third of the corresponding peak strength. Diagonal compression tests on specimens, conforming to ASTM E519 - 02 (ASTM, 2002), provided values for diagonal tensile strength (f t ) and shear modulus (G). Initial shear strength (f v0 ) and friction coefficient (μ) were obtained from triplet tests (three -unit specimens) under varying horizontal precompression levels and conducted parallel to the bed joints in line with EN 1052 - 3 (CEN, 2007). Finally, four-point bending tests on masonry wallettes, performed according to EN 1052 - 2 (CEN, 2016), provided flexural resistance in both vertical (parallel to the bed joints, f x1 ) and horizontal (perpendicular to the bed joints, f x2 ) orientations. For each direction, six specimens were tested under monotonic displacement control using a servo-hydraulic actuator, with three specimens loaded on the plastered face and three on the unplastered face, thereby capturing the influence of plaster position on flexural performance. Figure 1 illustrates the configuration used for both in-plane and out-of-plane testing. Quasi-static cyclic in-plane loads were applied to the frame’s top beam by a servo -hydraulic actuator anchored to a rigid steel reaction frame, while four inclined braces prevented any out-of-plane motion of the frame nodes. During these tests, the shaking table served as a fixed strong floor under active control. For out-of-plane testing, the actuator was detached and the existing out-of-plane restraints remained in place as ground motions were imposed by the shaking table. Specimens were securely fastened to the table to eliminate any relative movement between their foundation beam and the table surface.