PSI - Issue 11

Francesca Giulia Carozzi et al. / Procedia Structural Integrity 11 (2018) 355–362 F.G. Carozzi et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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Fig. 4. Localization of the LVDTs

5. Experimental results The experimental results are reported in Table 3. - is the maximum load applied on the diagonal, - represents the maximum shear stress. This value was computed according to ASTM E519-10: = 0.707 Where is the cross section transversal area computed as = ℎ+ 2 ( =1). - ΔLVDT is the relative displacement recorded by the four LVDTs

- The “pseudo - ductility” factor is computed as the ratio between the displacement reached at the peak load and the one reached at the end of the elastic phase. For the control sample and the reinforced with G-TRM and cG-TRM systems the values were computed with the average values recorded by the LVDTs, one parameter for the tension and one for the compression were analyzed. On the contrary it was not possible to evaluate the average value for the G TRM-NSM sample due to the different behavior of the two sides that present different reinforcement systems. For this reason two values are reported for tension and two for compression.

Table 3 – Experimental results

[kN] [MPa]

ΔLVDT1 [mm]

ΔLVDT2* [mm]

ΔLVDT3* [mm]

ΔLVDT4 [mm]

Pseudo-ductility factor [-] tension compression

Sample

DW_control DW_G-TRM DW_cG-TRM

32.07 113.57 130.59 54.91

0.07 0.26 0.30 0.13

4.56 2,43 2.38 0.55

-0.15 -1.13 -1.44 -0.11

-0.37 -1.84 -0.97 -1.29

4.58 2,43 1.77 2.81

16.36 31.86 11.05

2.63 7.27 3.87

DW_G-TRM-NSM

11.90 / 32.14

4.60 / 1.22

*negative values indicate compression The DW_control wall failed due to diagonal tensile cracking located in the vertical and horizontal mortar joints. 5a shows the load-displacement curves for the four LVDTs up to the maximum load. Two load cycles were applied, the first one in the elastic phase, at a load equal to 15 kN, the second one after the appearance of the tensile diagonal and to 0.2 mm in the compressive one. After the re-load cycle, there is an important cracking phase that reached a displacement in the tensile diagonal equal to 4.5 mm in correspondence of the maximum load. The cracks opening at the peak load generated a vertical drop in the load, with a residual displacement of about 4.3 mm. The load increased