PSI - Issue 44

Romina Sisti et al. / Procedia Structural Integrity 44 (2023) 1848–1855

1851

4

Romina Sisti et al./ Structural Integrity Procedia 00 (2022) 000–000

223 18 224 39 33 135 25 190 58 196 129 127

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Ambiguity Different judgement (only between forms and review) Different judgement (between forms) Accordance of judgement

5%

5%

6%

5%

6%

13%

15%

13%

12%

28%

18%

20%

12%

12%

31%

31%

39%

28%

33%

23%

16%

33%

98%

100%

77%

74%

% of churches

62%

61%

56%

54%

53%

52%

52%

39%

Apse

Dome

Façade

Chapels

Annexes

Transept

Bell tower

Prothyrum

Standing-out elements

Central nave

Lateral naves

Triumphal arch

Fig. 2. Results of the comparison between A-DC forms and the review of photographic documentation. The total number of churches in which each macro element has been analyzed is shown at the top of the relative bar.

This chart helps also in evaluating the weight of ambiguity for each macro-element since not all have the same impact on reaching agreement among technicians. Moreover, the impact of each issue should be compared with the number of cases in which the microelement is present. In the following, and overview is reported describing the main emerged issues for each microelement with the aim of understanding how to reduce this divergence. 3. Façade The first critical issue relating to the façade was observed in churches with a single entrance placed on one of the lateral walls. This generally occurs when the church is part of a masonry aggregate and the wall opposite the altar is adjacent to another building (Fig. 3a). Some technicians mistakenly describe the damage of the lateral wall with the entrance (wall panel in orange color in Fig. 3a) through the collapse mechanisms of the façade, while others, more correctly, use the mechanisms relating to the vertical structures of the principal nave. This difference is generated by the definition given in the user manual of the A-DC form where, based on a functional criterion, the façade is defined as the "wall panel, on which the main entrance is located". This definition contrasts with the identification of macro-elements based on structural and architectural criteria, according to which the façade is the transversal wall that delimits the nave and is usually opposite the position of the altar (wall panels in cyan color in Fig. 3a and in Fig. 3b). In this way it is possible to correctly identify the façade macro-element both in the cases of isolated churches (Fig. 3b) and in the cases of churches adjacent to other buildings (Fig. 3a). Another problem was found in churches with salient façades when the central part of the gable protrudes from the roof. The damage observed in the protruding portion (green portion in Fig. 3c) is sometimes describe through the M2 mechanism (overturning of the gable), other times through the M26 mechanism (standing-out elements). In these cases, the first solution is more convenient, as it allows the M26 mechanism to be used to describe the damage reported by any other standing-out elements. Furthermore, the use of the M2 mechanism is more consistent with the approach used in churches with quadrangular façades (Fig. 3d), where the damage of the top corners is described through this mechanism.

b

c

d

a

Fig. 3. a) Church adjacent to other buildings (grey blocks) with the entrance on a lateral wall. d) Isolated church with the entrance on façade wall panel. c) Church with a salient façade. d) Church with a quadrangular façade.