PSI - Issue 64

Isabella Mazzatura et al. / Procedia Structural Integrity 64 (2024) 114–121 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

118

5

Configuration I Configuration II Configuration III Configuration IV

200

180

160

Linear regression y=-35.397+138.74x y=-40.99+148.05x y=-39.325+141.8x y=-47.064+131.09x y=-44.517+142.37x

140

Configuration I Configuration II Configuration III Configuration IV All configurations

120

100

Heigth [cm]

80

60

40

20

0

-2

-1

0

1

2

3

4

Error [cm]

Fig. 5. Linear regression in between error and height of the ducts for the four Configurations. The red line represents the regression of the data considered all together (all the configurations, all the concrete covers, alle the walls).

3.2. Influence of the concrete cover depth

The other investigated parameter is the concrete cover depth. Table 2 shows the main statistical parameters of the location error of the duct. Both the mean and the median, and both the standard deviation and the interquartile range are given. Fig. 6 shows the histograms of the error considering a bins’ amplitude of 1 cm. The distributions are approximately normal for every configuration, and also the statistical parameters are similar for 15 and 25 cm concrete cover. The potential influence of the concrete cover depth is assessed by relating the errors and the average height at which the duct is located. As Fig. 7 shows, the two cases result in a very similar regression line. The maximum accuracy of the instrument is at a height between 141 cm and 145 cm for both cover thickness, and a clear trend can be identified. Therefore, also in this case the relative vertical position of the duct seems to be a factor of influence even stronger than the concrete cover depth.

Table 2. Statistical parameters of the location error considering 15 cm and 25 cm concrete cover. Configuration Wall Concrete Cover Mean (cm) St. Dev. (cm)

Median (cm)

IQR (cm)

All All

All All

E1 E2

0.54 0.67

1.41 1.56

0.5 0.5

2.0 2.5