PSI - Issue 44

Mariateresa Guadagnuolo et al. / Procedia Structural Integrity 44 (2023) 878–885 M. Guadagnuolo et al. / Structural Integrity Procedia 00 (2022) 000–000

882

5

• In-plane loading: involving eccentric loads and thrusts of arches and vaults. In this paper, attention is paid to the index that refers to vertical actions MQI V . The parameters included represented the rule of art are: • SM: Mechanical characteristics and quality of masonry units; • SD: Dimensions of the masonry units; • SS: Shape of the masonry units; • WC: Level of connection between adjacent wall leaves; • HJ: Horizontality of mortar bed joints; • VJ: Staggering of vertical mortar joints; • MM: Quality of the mortar/interaction between masonry units. For each of them, one of three grades is assigned, Fulfilled—F, Partially Fulfilled—PF, and Not Fulfilled—NF. The combination of the parameters and their respective ratings provides a MQI to different actions. an MQI value for the different actions. Depending to the fulfilling of MM parameter for squared-block masonry a multiplicator factor r v is used. The quality of the mortar is taken into account by two parameters. The first one is the m parameter, which applies a 30% reduction of the MQI values to the mortar in a state of severe degradation. The second one is the g parameter which applies a further 30% reduction to big joints (over 13 mm height). In order to calculate MQI v , the method provides the following formula: ! = ∙ ∙ " ∙ " ∙ ( ! + ! + ! + ! + ! + ! ) (1) The procedure establishes that for each MQI value, a range determines the masonry score for each type of action. The score is A for good quality masonry, B for average quality, and C for inadequate. The results of the MQI v evaluation for the ten masonries are presented in table 2. For each MQI value, a correlation with the main mechanical properties of the masonry was identified (Borri et al. 2020). The parameters f m and E depend on IMQ v , respectively, for type A, B and C masonry, according to the following relationships: #$% = 1.892 ∙ &.()*(,-. ! ) ; #0$1 = 1.444 ∙ &.(23(,-. ! ) ; #41 = 1.055 ∙ &.(56(,-. ! ) (2) #$% = 876 ∙ &.(*((,-. ! ) ; #0$1 = 742.1 ∙ &.(*6(,-. ! ) ; #41 = 608 ∙ &.(*7(,-. ! ) (3) As shown in table 2, for the selected Campania walls made of yellow tuff the MQI v value does not exceed 5, highlighting the poor quality of masonries if referred to the maximum of 10 indicated in the MQI method. It can also be noted that the C-scored masonries are characterized by a f mm value lower than 2 MPa. Indeed, according to the authors' experience (D’Amato et al. 2022), a mortar with f mm under 2 MPa could be considered a mortar in a bad state of conservation.

Table 2. MQI method applied to ten masonry

MQIv (vertical actions)

f mm [MPa]

SCORE

Masonry

SM

SD

SS

WC

HJ

VJ

MM

m

g

M1 M2 M3 M4 M5 M6 M7 M8 M9

F F F

PF

F F F F

PF PF PF PF PF PF PF PF PF PF

PF PF

PF NF PF NF NF NF NF

PF PF NF PF NF PF PF NF PF PF

NO NO NO NO

NO

3.90 2.73 1.05 2.94 0.34 4.50 1.62 1.60 3.60 1.12

B B C B C B C C B C

-

F F

YES YES

2.10 1.80 2.50 1.50 1.50 1.95 3.36 1.47 -

F F

PF

PF

NO

F F

F F

PF

NF

YES

YES

F

F F F F

NO

NO NO NO NO NO

PF

PF

PF

YES

F F F

F

F

F

NO NO

PF PF

PF

PF PF

M10

F

PF

YES