PSI - Issue 44

Rebecca Asso et al. / Procedia Structural Integrity 44 (2023) 894–901 Rebecca Asso et al./ Structural Integrity Procedia 00 (2022) 000–000

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one-day time frame is used. The moving mean is a method that evaluates the mean value for a given set of data across a specified time period. Equation (1) depicts the formulation that defines the moving mean.

i z = å i j

i c

= =

µ

(1)

n

Where j and z represent the indices of the measured data domain. Standard scores, also known as z-scores, are statistically used to identify outlier displacements by means of a threshold that provides an acceptable curve of data points. The statistical approach highlights a value based on the difference between the distance from the mean and the standard deviation (Brase and Brase 2013). The expression in Equation (2) determines the standard score.

c µ s -

z

=

(2)

In Figure 5a and Figure 5b are displayed the datasets of the pre-retrofitted and post-retrofitted stages of pile 1.

a) Pre-Retrofitted Pile 1 – Sensor 1

b) Post-Retrofitted Pile 1 – Sensor 1

Figure 5: Correlation of temperature and displacement post-processing

The temperatures that have been processed are evaluated, and one time frame for each dataset is chosen in order to have the same temperature variation (ΔT). The ΔT for the Dataset 1 is found to be 10.43 °C and 10.53 °C for the Dataset 2. Table 1 and Table 2 illustrate the maximum and minimum displacements from both datasets, which are analyzed and compared with the FEM model.

Table 1:Measured displacements of Pile 1

PILE 1

Displacement of Sensor 1

Displacement of Sensor 2

S max [mm]

S min [mm]

ΔS [mm]

S max [mm]

S min [mm]

ΔS [mm]

Pre-retrofitted Structure Post-retrofitted Structure

16.06 21.41

-1.24 11.31

17.3 10.1

24.72 32.65

-4.83 16.11

29.55 16.54