Sensor Placement Strategies for the Seismic Monitoring of Complex Vaulted Structures of the Modern Architectural Heritage

Table 2

Modal properties of Hall B and classification of the main vibration modes, considering the presence of the infill walls.

Mode	Frequency	Mass fraction			Mode classification
	Hz	x	y	z
1	1.770	0.119	0.000	0.000	1st bending X: vault
2	1.937	0.001	0.000	0.000	2nd bending X: vault
4	2.203	0.000	0.082	0.000	1st bending Y: front tympanum
7	2.660	0.000	0.017	0.002	2nd bending Y: vault and aspe
9	2.863	0.000	0.156	0.000	3rd bending Y: pounding between the apse and the vault
11	2.927	0.000	0.195	0.000	4th bending Y: vault and apse
17	3.452	0.230	0.000	0.000	Aspe mechanism
26	3.981	0.246	0.000	0.000	Vault and fanned elements
32	4.507	0.000	0.001	0.003	Vault and fanned elements
39	4.945	0.000	0.040	0.011	Apse and tympanum
47	5.379	0.000	0.058	0.010	Apse and tympanum
50	5.505	0.125	0.000	0.000	Vault
53	5.694	0.000	0.000	0.000	Tympanums mechanism
66	6.306	0.000	0.005	0.561	Vault
97	7.297	0.007	0.000	0.000	Vault and apse