A Study on Challenges in the Rehabilitation of Large Masonry and Concrete Dams

Abstract

Large dams retain enormous volume of water intended for various purposes. The design, construction, operation and maintenance of these special structures are of paramount importance considering its uses and safety. Safety of the dam is to be ensured throughout its’ life from structural, hydrological and operational perspectives as its failure would be catastrophic. Periodical safety inspections, review on safety, dam health monitoring as well as risk assessments are measures to ensure safety of these large structures. Ageing of dams is a concern in dam safety as there can be inadequacies or deficiencies with respect to structural, hydrological and operational requirements. Revision of relevant codes of practice/standards also may necessitate review and strengthening. As such, these structures are to be rehabilitated to the prevalent standards and maintained healthy to continuously derive the benefits envisaged during construction. Rehabilitation of dams aims to bring it back to a good condition and ensure that it does not pose a risk to the stakeholders downstream. The process involves various systematic procedures such as review of structural design, review of design flood and diagnosis using non-destructive tests to detect possible deterioration in its health, etc. As per recent statistics, more than half of the large dams in India are more than 25 years old. In this paper, a review of aspects such as challenges, considerations as well as various factors involved in the effective implementation of rehabilitation/strengthening is presented. Certain case studies of rehabilitation work undertaken under the on-going Dam Rehabilitation and Improvement Project in India are cited to bring forth the importance of such measures. As dams play crucial role in the prosperity of the nation, they are to be maintained for an endured life without jeopardizing the safety of the structure. In that perspective, rehabilitation of dams or its strengthening process is extremely important.