HYDRAULIC AND STRUCTURAL ASSESSMENT OF THE RAVI SYPHON STRUCTURE FOR UP GRADATION

Abstract

The canal system in District Lahore and Kasur Irrigation Divisions have been suffering from shortage of water for a long time, due to reduction in capacity of Ravi Syphon (4200 Cs) as compared to design capacity (4853 Cs) at BRBD Link Canal which is outlived being a 70 years old structure. Irrigation Department carried out an underwater inspection of the Ravi Syphon with the help of divers in 2007.About 33% of the overall length could only be examined due to limitations and constraints. The inspection of Ravi Syphon structure is carried out recently though out the length of barrels (100%) by Irrigation Department and consultant whereas I supervise the inspection of barrels as Sub Divisional Officer, Ravi Syphon. Underwater and dry inspection of barrels were done through divers and recorded the images and videos for assessment of heath of structure. The results of underwater inspection revealed that the concrete face has been eroded at the syphon inlet leaving coarse aggregate exposed and in some places reinforcement steel bars are exposed. Many of the barrel joints were found to be leaked. Traverse joints in all five barrels were found to be in poor condition. Cracks in the concrete of the five barrels were observed. Two large holes were found in one of the barrels. Water stops are exposed at many places. In this research repairing of existing barrels is recommended by using sprayed concrete (shotcreting or guniting) for the top and sides of the barrel with reinforced concrete at the base. The proposed thickness of sprayed concrete is 2 inches (50 mm) and that of reinforced concrete is 4 inches (100 mm). Repairing of the damaged upstream bed protection is essential and proposed that scour holes should be rock filled.