## 2 Analyzed Ceilings  
The following ceiling systems were analyzed: a prefabricated prestressed Smart channel ceiling and Teriva Panel, Teriva Base, Teriva Plus and Teriva Termo ribbed ceilings. The Smart ceiling is a 60 cm wide prestressed concrete slab with five \(60\times 90\) mm air ducts, and reinforcement in the form of six \(\circ\) 9.3 mm rods in the bottom part and two \(\circ\) 6.85 mm rods in the top part. The section of the Smart ceiling is shown in Figure 1. The lateral edges of the prefabricated element are shaped so that after filling them with concrete, a permanent connection will occur, which will ensure proper cooperation between the panels when transferring loads. The most important parameters of the ceiling in question are summarized in Table 1. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline height & 150 mm \\ width & 600 mm \\ transferred loads depending on the span & from 5.0 to 40.0 kN/m\({}^{2}\) \\ prefabricated concrete class & C40/50 \\ span up to & 8.1 m \\ fire resistance & REI 60 \\ weight & 250 kg/m\({}^{2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Basic parameters of the Smart ceiling. Figure 1: Cross-section of the prefabricated prestressed Smart ceiling. 1—prefabricated prestressed slab, 2—stressing cables, 3—concrete laid on site. The Teriva Panel ceiling is a prestressed composite structure with reinforced concrete laid at the construction site. The prefabricated prestressed part consists of a bottom plate 590 mm wide and two ribs. The space between the ribs is filled with foam concrete with a density of 400 kg/m\({}^{3}\), and a 4 cm layer of composite concrete is poured into the whole structure at the construction site. The cross-section through the Teriva Panel ceiling is shown in Figure 2, and its basic parameters are given in Table 2.  
The Teriva Base ceiling system consists of prefabricated truss beams with a concrete foot, three-chamber filling expanded clay, and concrete hollow bricks and concrete overlay laid at the construction site. The cross-section of this ceiling is shown in Figure 3, and the basic parameters are given in Table 3. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline height & 160, 180, 200 mm \\ width & 600 mm \\ transferred loads depending on the span & from 2.0 to 34.4 kN/m\({}^{2}\) \\ prefabricated concrete class & C40/50 \\ span up to & 7.4 m \\ fire resistance & REI 30 \\ weight & 188 kg/m\({}^{2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Basic parameters of the Teriva Panel ceiling. Figure 3: Cross-section of the Teriva Base thick-ribbed ceiling. 1—prefabricated truss beam, 2—filling expanded clay and concrete hollow brick, 3—concrete laid at the construction site. Figure 2: Cross-section of the partially prefabricated prestressed composite Teriva Panel ceiling. 1–prefabricated prestressed slab, 2–stressing cables, 3–concrete laid on site, 4–foam concrete. The Teriva Plus system is similar to the Teriva Base ceiling, but their difference lies in the type of filling. In the Teriva Plus case, the filling is expanded clay and concrete five-chamber hollow bricks in the so-called upper shelf as shown in Figure 4, which remains uncovered after pouring concrete into the ceiling. Thanks to this solution, the height of the complete ceiling is equal to the height of the hollow brick itself. The basic parameters of the Teriva Plus ceiling are summarized in Table 4.  
The Teriva Termo ceiling is characterized by the use of expanded clay and concrete 10-chamber hollow bricks with shifted vertical walls, as shown in Figure 5. This solution eliminates the occurrence of direct thermal bridges between the upper and lower surfaces of the hollow brick, which in turn should improve the thermal properties of the ceiling. The basic parameters of the Teriva Termo ceiling are summarized in Table 5.