PSI - Issue 44

Carlo Vienni et al. / Procedia Structural Integrity 44 (2023) 2270–2277 Vienni et al. / Structural Integrity Procedia 00 (2022) 000–000

2275

6

a

b

c

d

Fig. 4. (a) Strength; (b) stiffness; (c) displacement amplification coefficient; (d) wall’s thickness influence on strength amplification coefficient .

The equivalent parameters of compressive strength f c,R and tensile strength f t,R to be applied to reinforced masonry can be calculated using the following formulations:

(1) (2)

where f c,URM and f t,URM are resistances of unreinforced masonry, f t,pl is the tensile strength of CRM plaster obtained from the load at the first cracking of coupons subjected to clamping-grid tests, t pl is the overall thickness of plaster (i.e. 30+30=60 mm) and t URM the wall thickness. The correction coefficients applied to formulations (1) and (2) have been calibrated by numerical regression to minimize the difference between amplification coefficients obtained through the FEMmodel and analytical procedure. The average difference between the values obtained through the two procedures is less than 5%. In Table 4 an example of the application of analytical formulations for brick masonry walls is shown and the differences with numerical results in terms of strength and stiffness amplification coefficients are pointed out.

Table 4. Application of analytical formulations for brick masonry walls. Masonry type Compression v=σ/fc α V = V RM /V URM Numerical α V = V RM /V URM Analytical

α K = K RM /K URM Numerical

α V = K RM /K URM Analytical

Δ [%]

Δ [%]

0,05 0,15 0,30 0,50 0,75

1,01 1,28 1,34 1,45 1,53

1,00 1,22 1,35 1,36 1,59

1% 5%

-

-

-

1,42 1,51 1,41

1,41 1,41 1,41

1% 7% 0%

Existing brick t=250mm

-1%

7%

-4%

-

-

-