PSI - Issue 29

R. Gagliardo et al. / Procedia Structural Integrity 29 (2020) 48–54 R. Gagliardo, G. Terracciano, L. Cascini, F. Portioli, R. Landolfo/ Structural Integrity Procedia 00 (2019) 000 – 000

52

5

Both associative and non-associative flowrules were considered in the paper. The choice of the flowrule affects the numerical procedure in terms of quality of collapse mechanism and CPU time. In the case of non -associative solution, the fa ilure mode is not affected by block dila tancy, but the CPU time is larger because of the iterative procedure adopted. The value of the base reaction at collapse is equal to 881.75 kN and 898.85 kN in the case of associative and non-associative solutions respectively. The numerical results show the computational ability of the procedure to find the solutionof thenumerical problem in very fewiterationsas showed in theconvergence plot (Fig. 3b) and thehigh speedof calculation (CPUTime in Table 1).

0 100 200 300 400 500 600 700 800 900 1000

Base Reaction - [kN]

0

1

2

3

4

5

6

Iteration number

a)

b)

Fig. 3. (a) Collapse mechanism of the façade subjected to settlement (non-associative solution); (b) convergence plot.

Table 1. Numerical results.

Associative Solution

Non-Associative Solution

Model size (block x contacts)

μ [-]

ρ [kN/m 3 ]

Base Reaction [kN]

CPU Time [s]

Base Reaction [kN]

CPU Time [s]

1873 x 20176

0.60

18.00

881.75

2.68

898.85

23.63

4. Conclusions A numerical procedure for limit analysis of monumental masonry structures subjected to settlement-induced foundation movements was presented in the present conference paper. The model is based on a contact point formulation, assuming infinite compressive strength and zero-tensile strength. The numerical approach was applied to the case studyof a Romanesque church façade, with pointed arch doors and rosewindows. Thefaçadewas involved in a settlement a t half of the base length. The outcomes were presentedand discussed in terms of loss of thereaction a t the baseand crack patternof the façade. Theability of the numerical procedure was discussedconsidering the time of ca lculationand the convergenceof the iterativeprocedurefor the non-associativesolution. Acknowledgements The financial support of PRIN2015 Programme by the Ministry of Education, University and Research (MIUR) is gra tefully acknowledged for funding the research project “Protecting the Cultural Heritage from wa ter -soil interaction rela ted threats” (Prot. No. 2015EAM9S5), which is the ma in framework of the study presented in this article.