PSI - Issue 44

Romina Sisti et al. / Procedia Structural Integrity 44 (2023) 1848–1855 Romina Sisti et al./ Structural Integrity Procedia 00 (2022) 000–000

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2. Comparison between cards relating to the same church compiled by different technicians The analysis reported in this paper was conducted on a set of 225 churches on which two separate surveys were carried out in different phases of the 2016/17 Central Italy seismic sequence because of the worsening of the damage condition. The analyzed database is therefore composed of a total of 450 A-DC forms compiled by different research units: the University of Camerino and the Polytechnic University of Marche, the University of Genova, the University of Napoli Federico II, the University of Padova and the University of Perugia. In particular, 225 survey forms, i.e., those referring to the first of the two forms carried out for each considered church, were filled in the first phase of inspections, whose damage can be traced back to the 24 August shock. On the other hand, the second survey forms were filled in the second phase of surveys whose damage can be traced back to the shocks of the end of October (surveys from 2016/11/01 to 2017/01/18), while 182 in the third and final phase of surveys following the last major shocks of 18 January 2017 (surveys from 2017/01/23 to 2017/05/12). Comparison of the damage section of the forms filled out on the same church during the first and second inspections revealed a great lack of uniformity of judgement regarding the mechanisms considered to be activatable (Fig. 1). Given these large discrepancies, the photos and notes attached to the form of each church of the database were reviewed in detail and if necessary supplemented by additional web searches, comparing what was observed with the results obtained from the analysis of the two forms. Specifically, during the review phase, particular attention was paid to the presence/absence of all the different macro-elements, carefully following the definitions and indications given in the user manual of the A-DC form (Presidenza del Consiglio dei Ministri and Dipartimento della Protezione Civile, 2011), and noting any ambiguities derived from non-standard configuration of the churches. In the case of a shortage of photographic material that did not allow for an accurate assessment, the church was excluded for the purposes of the analysis. In the elaboration of the data of A-DC forms a macro-element was considered to be present when at least one mechanism associated with it, according to what is reported in Table 1, was marked as activatable. The results are shown in Fig. 2, reporting four different cases. In the first case (green color) the presence of the various macro-elements results from both forms and was confirmed by the subsequent review. The second case (pink color) includes churches with forms that report different judgement, while the case in which consistent information emerged from the two forms, but disagreed with what was subsequently assessed by the review of the photos is indicated in red color. Lastly, a further case was identified in yellow color when difficulties were encountered in establishing the presence or absence of the macro-element (ambiguity). Each macro-element will therefore be specifically elaborated in the following paragraphs, with some general considerations and analysis of recurring cases.

222 222 224 18 225 224 35 105 29 26 25 22 121 22 12 163 188 138 220 25 144 55 58 47 185 131 111 115

100%

Accordance of judgement Different judgement

3%

4%

5%

13%

10%

14%

16%

80%

19%

23%

24%

25%

33%

33%

34%

34%

35%

36%

36%

39%

39%

40%

41%

42%

43%

44%

44%

44%

45%

60%

40%

97%

96%

95%

90%

87%

86%

84%

81%

77%

76%

75%

20% % of churches

67%

67%

66%

66%

65%

64%

64%

61%

61%

60%

59%

58%

57%

56%

56%

56%

55%

0%

M1

M2

M3

M4

M5

M6

M7

M8

M9

M10

M11

M12

M13

M14

M15

M16

M17

M18

M19

M20

M21

M22

M23

M24

M25

M26

M27

M28

Fig. 1. Normalized percentage of churches with accordance of judgement for possible mechanisms and different judgement between the two survey forms. For each mechanism, the percentages were calculated with reference to the number of churches in which the mechanism was considered possible in at least one of the two survey forms (number shown at the top of the bar of each mechanism).

Table 1. Association between the macro-elements and the 28 mechanisms of the A-DC form. Macro-element Mechanisms Façade

M1 (overturning), M2 (upper façade overturning), M3 (in-plane mechanisms)

Prothyrum and narthex

M4

Central nave Lateral naves

M5 (transversal mechanism), M6 (in-plane mechanisms), M8 (vaults of the nave), M19 (roof)

M7 (colonnade), M9 (vaults of the lateral naves)

Transept

M10 (overturning), M11 (in-plane mechanisms), M12 (vaults), M20 (roof)

Triumphal arch

M13

Dome Apse

M14 (dome and tambour), M15 (skylight turret)

M16 (overturning), M17 (in-plane mechanisms), M18 (vaults), M21 (roof) M22 (overturning), M23 (in-plane mechanisms), M24 (vaults)

Chapels Annexes

M25 M26

Standing-out elements

Bell tower

M27 (bell tower), M28 (bell cell)