PSI - Issue 52

Rakesh Katam et al. / Procedia Structural Integrity 52 (2024) 72–88 Rakesh Katam/ Structural Integrity Procedia 00 (2019) 000 – 000

80

9

B4

Color less

Carbonated

The half-cell potential method is used for the in-service evaluation of reinforcement. By measuring the steel's half cell potential, which indicates the risk of corrosion in the reinforcement of a certain structural element, the behavior of the material can be ascertained. Reinforcing steel corrosion is an electrochemical process. Column A3 in Table 6 has an average measured potential of -314 millivolts and is 1.2 m off the ground. Corrosion may or may not happen because of the element's intermediate corrosion probability. Column B3, on the other hand, is 0.6 m from the ground and has an average measured potential of -373 millivolts. With a less than 90% likelihood, corrosion in this column is highly probable. This suggests that corrosion is highly likely, and prompt corrective action is needed to stop additional damage.

Table 6. Half-cell potential results for different structural elements. Element no. Location ID Avg. measured potential

Probability of corrosion

A3 B3

1.2m from FL 0.6m from FL

-314 -373

Intermediate <90% (High)

According to the findings of the NDT tests (Hussein et al. (2021)), the state of the existing concrete column is variable and necessitates numerical analysis to determine the structural integrity of the present building. The following tests have been carried out to determine the surface hardness, integrity, and depth of carbonation for concrete: RH, UPV, (Gavela et al. (2021)) and carbonation tests. Combining these results will give an idea of the concrete's quality, but if the same test is run on a specific element at different levels, the results may vary at each level, producing multiple results for that element. To avoid these issues and increase safety, average values are considered when analyzing a structure. M15 is the concrete grade considered for the study to understand why the cracks appeared in all columns. A profo-meter and a half-cell potential are employed for rebar identification and corrosion rate. This test provides information on the rebar's location and the corrosion likelihood in the reinforcing steel. The likelihood in this instance ranges from modest to high. Through NDT, we were able to determine the concrete and rebar properties for the numerical analysis. 3.4. Numerical Analysis A 3D numerical model was developed using ETABS to better understand the structure's overall behavior. Three numerical models were made in order to understand the structure's capacity to support loads. The first model was

Fig. 8. Numerical model (a) plan view; (b) 3D view; (c) model analysis.