Design and supplying erection system for steel linings of Pressure and Surge Shafts of UmaOya HPP Project

OmaOya project is a multipurpose development project (water transmission between two basin, generating electric Power and Flood Control) in Sri Lanka that is under execution by Farab Company. Waterways of this project contain a Pressure Shaft with rare height of 620m and a Surge Shaft of 140m height. Because of technical necessity (critical path of the project and safety of erection personnel against rock fall from shaft wall), design and supplying of Erection System was ordered to DSDA. An Innovative solution patented by DSDA that contrary to usual practice (transporting the segment from top to bottom and erection from bottom to top), the segment of steel lining are transported from bottom of shaft upward and are welded to each other hanging to a saddle on top of the shaft. . During erection, all personnel are safely inside the steel lining protected from falling stones and water splash. The erection of this steel lining is done successfully in 2017 to 2018 within its time frame.