Medigadda barrage undergoes electrical resistivity test for structural integrity

Top officials of the Irrigation Department made it clear that the investigation as well as the rehabilitation would solely be the responsibility of the implementation agency.

Hyderabad: As part of the end- to- end investigation of the Medigadda barrage structures that got underway, the project authorities have opted for electrical resistivity test. It is intended to assess the durability of the concrete structures. The testing process which commenced on Thursday would be completed within a week. Basing on the findings, the final investigation report would be prepared for submission to the government which had already ordered a judicial probe into the sagging of the barrage piers.

The L&T company, which constructed the Medigadda barrage has taken up the electrical resistivity test. Top officials of the Irrigation Department made it clear that the investigation as well as the rehabilitation would solely be the responsibility of the implementation agency.

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As sought by the dam safety experts, the barrage was totally drained and the work area was cleared to facilitate a thorough investigation. A cofferdam was constructed to keep the structure impacted due to sagging of piers at Medigadda free from water. The investigation report would be ready by January 15, they added.

The officials said that the entire length of the barrage would be examined for structural issues by conducting the electrical resistivity test. It is one of the foolproof methods to decide the fate of the structures impacted for any reason, explained the officials. They further added that the State government would take a call on the issues involved in the rehabilitation after a thorough study of the investigation report. Three of the piers would which were impacted in a big way, would be dismantled by adopting the diamond cutting method. The impact of sagging was evident on three more piers also.

Sundilla barrage is leakage free

The electrical resistivity test was conducted first on Sundilla barrage. Pressured grouting was taken up after identifying certain issues. The work has been completed and the barrage was made leakage free. The rehabilitation works on the barrage were done by the implementation agency as part of the contractual obligation.

Tests of the electrical resistivity method would be conducted in Annaram barrage also very soon. The grouting works on the barrage were in progress. The seepage issues identified at places were being addressed. Despite all out efforts being made by the department, provision of ater to the Rabi ayacut this year would be a remote possibility, they clarified.

What is electrical resistivity test?

To put it in simple terms, its like taking an X- Ray of the sub surface. This test is used to evaluate the electrical resistivity of water-saturated concrete.

It will provide a rapid indication of the concrete’s resistance to chloride ion penetration. The process helps in identifying the depths to which the chloride ions penetrate into the concrete indicating the extent affected by corrosion in RCC structures. The tests of chloride permeability are an important aspect helping in assessing the durability of the concrete structures.