Evaluation of epoxy grout for roller path repairing
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Date
2014-06-26
Authors
Chen, Jingang
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Abstract
Manitoba Hydro owns and operates 12 river hydroelectric generating stations ans two major control structures. The structures control the flow of water almost exclusively with gate wheels. It is important for the roller paths to remain true to allow uniform distribution of the hydraulic load on the gates to the gate wheels. Manitoba Hydro is currently replacing the distorted steel roller paths at its MacArthur Generating Station.
The purpose of this study was to evaluate the physical properties of high strength proprietary grouts to determine their adequacy for use beneath new roller paths of water control gates which have unusual spacial constraints. Two full size mockups of a portion of an existing guide, with a steel overlay, were utilized in the experimental study.
To investigate the stress-strain distribution in the mockup under specific loading condition, strain gauges were installed on both of the web sides of the embedded steel I-beam: one group of gauges was located just below the flange, the others were located along the mid-hight of the beam web. Force gauges were inserted to measure the pressure between the thin grout layer bottom and the top of the embedded I-beam. A special LVDT (linear variable differential transducer) assembly was made to measure the maximum displacement of grout layer. Mockup samples were subjected to static and cyclic loading procedures at two designated loading points. The grout cylindrical creep tests were conducted at the same time. It included tests at room temperature and at the elevated temperature of 50°C. The initial sustained load was 50% of the ultimate compression strength of the grout cylinder (3"x6"). Once the creep development was observed to become constant, the sustained load was raised up to 70% of ultimate strength and held constant until the end of the test.
The test results indicate that the strength of the proposed grouting material is adequate to resist the required load, both statically and cyclically. Temperature has no significant effects on this specific loading situation. The proposed grouting method is proven to be simple, economic and efficient, therefore, the technique is suitable for roller path repairing.
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Keywords
Grout, Roller path, Water control gates