Issue 29

L. Contrafatto et alii, Frattura ed Integrità Strutturale, 29 (2014) 196-208; DOI: 10.3221/IGF-ESIS.29.17

assumed, on the basis of the experimental evidence. The cubic function in Fig. 15, depending only on two constitutive parameters, was selected.

40

Experimental Mohr-Coulomb SDA

30

20

10

PULL-OUT FORCE [kN]

0

0

1

2

3

4

5

DISPLACEMENT [mm]

Figure 14 : SDA simulation by code FracSDA8 of test B-10-3. Pull-out force and stress distribution at the peak load.

5 du f

t

0

   

   

2

3

 

0     du du   t

0     du du   t

du du





f

5

4.5

1.4

t

0       t

 

0



 

f

if

du du

0

t

t



0

1.9 t  Figure 15 : Bond slip model. Interface stress versus shear slip. t if du du  f

Table 3 reports the parameters value assumed in the calculations. The predictions were once again accurate, both in the estimation of the pull-out strength and in the prediction of the failure mechanism. For example, in Fig. 16 the results concerning test B-14-10 are reported. The maximum value of parameters in Table 3 were used. The steel bar rupture and the corresponding anchor strength are correctly reproduced, as it can be observed by the comparison between pictures 16 and 5.

Initial Tangent Stiffness 5 f t /  d u 0 [N/mm 3 ]

Shear Slip d u 0 [mm]

Constant

1.9 f t

[N/mm 2 ]

Basalt

50000 20000 11000

35 ÷ 50

0.1 ÷ 1 0.1 ÷ 1 0.1 ÷ 1

Limestone Sandstone

15

2 ÷ 5

Table 3 : Bond slip model parameters

205