Rehabilitation of Chenderoh dam and spillway

摘要

The Chenderoh dam was constructed during the period 1927―1930 on Perak River in the State of Perak Darul Ridzuan, Malaysia to provide a source of hydroelectric power for the state. It is a 22 m high hollow concrete buttress dam. Over the years modifications have been made to the original dam structure to increase its spillway crest level by 1.7m from elevation 58.8m to 60.5m and its abutment crest walls heights from elevation 67.7 m to 68.9m. In the mid fifties, cracks were observed on the dam particularly in the buttresses and piers and concrete in certain areas was found to have deteriorated. The integrity and safety of the dam was a cause for concern. Measures were taken shortly to monitor the cracks development and the dam performance. Inspection and investigation works were carried out to determine the causes of the cracks and to recheck the design of the dam. The findings did not reveal any unacceptable stress conditions. A feasibility study of rehabilitating the Chenderoh station including the dam was conducted in 1986. The study report concludes among other things that the cracks are due to the cooling strains and drying shrinkage, and are generally of little significance from structural point of view. Nevertheless, recommendations and proposal are made in the report to repair all deteriorated concrete and to seal all the cracks as to restore concrete strength in those affected areas and to inhibit the ingress of water into the areas of reinforcing steel. The recommendations and proposal for the rehabilitation of the Chenderoh dam was accepted and implemented when the decision was made to rehabilitate the Chenderoh power station. The rehabilitation works of the dam were carried out during the period between mid 1995 to end 1996.