PSI - Issue 78

Giada Frappa et al. / Procedia Structural Integrity 78 (2026) 17–24

19

All the walls, including those of the elevator core, have a thickness of 120 mm and a length of 6.76 m. Their reinforcement consists of a mesh of ϕ 8 mm bars arranged at 250 mm spacing in both the vertical and horizontal directions, with a concrete cover of 21 mm. The beams are precast prestressed RC elements with lateral corbels to support floor units. Structurally, they behave as simply supported beams in the X direction. The beam cross-section is tapered at the ends to facilitate the connection with the columns (Fig. 3), while the depth is constant and corresponds to the floor thickness (450 mm). The main interior beam exhibit a constant inverted T-section with a bottom flange width of 1040 mm and a top flange width of 800 mm (Fig. 4a). The perimeter beams are quite similar, but exhibit a L-section instead of inverted T one and have bottom and top flange widths of 920 mm and 800 mm, respectively. Longitudinal non-prestressed reinforcement (indicated as black circles in Fig. 4) consists of 16 mm and 26 mm diameter bars, while prestressing tendons (white circles) have a diameter of 0.6 inches (15.24 mm). The prestressing load on each tendon i s 185 kN . Transverse reinforcement includes 8 mm diameter stirrups and additional bent bars or stirrup holders with diameters of 10 mm or 12 mm. In the Y direction, only perimeter RC tie beams are present. These have cross-sections of 400 × 450 mm² at the first-floor level and 300 × 450 mm² at roof level, and are anchored to the primary beams via mechanical connections.

(a)

(b) Fig. 3. Longitudinal vertical (a) and horizontal (b) sections of the central beams. In the horizontal section, on the left side the bottom reinforcement, and the right side the top reinforcement (from documents provided by Resia Municipality).

(a) (b) Fig. 4. Cross section along the span (left) and at the support point (right) for: (a) central beam; (b) perimeter beam (from documents provided by Resia Municipality). Floor systems at the first and attic levels consist of one-way RC hollow-core slab panels spanning in the Y direction. These precast elements are 450 mm deep and have nominal widths of 1.80 m or 2.40 m (Fig. 5), depending on their location. The slabs are supported by the main beams previously described. The ground floor system is composed of precast prestressed RC Π -section elements.

(a) (b) Fig. 5. Cross section for (a) slab 1800 mm wide; (b) slab 2400 mm wide (from documents provided by Resia Municipality).