After a lengthy process of preparation, the first significant hydraulic steel structures are being installed by the Whessoe/KGAL team at the 1285MW Xayaburi hydroelectric project in Northern Laos.
Activities leading up to this major milestone included the construction of an on-site manufacturing facility, enabling the production of much larger parts and eradicating the constraints of transportation to site on the public roads.
First to be installed are the navigation lock mitre gates. Each pair is 12m span and 30m deep, with a combined weight of 320 tonnes, complete with integral balancing sluice gates. Each mitre gate leaf was transported the two miles from the manufacturing facility to the navigation lock site in two pieces and assembled at the lock. There are three pairs of mitre gate in the lock, in addition to water feed and fish attraction sluice gates.
Following on close behind the mitre lock gates are the low-level outlet radial gates, located in the lower level of the spillway structure. Each of the four radial gates is 12m span and 16m deep, with a design head of 37m and weighing 400 tonnes each.
All of the gates on the project have been designed by KGAL in the UK, with full seismic assessment to the latest ICOLD requirements. Workshop drawings were prepared by Whessoe in their Manila office and signed off by KGAL before being released for manufacture on site.
"This is a significant step change in the approach to gate manufacture; it is usual for gates to be manufactured off-site and transported long distances to the project," said KGAL Director, Dave Griffiths. "In the case of Xayaburi, Whessoe decided to create an integrated manufacturing facility at the site, complete with CNC machining and painting facilities specifically designed and procured to deal with the large gates on this project."
Xayaburi is the latest in a long line of projects where KGAL and Whessoe engineers have worked together, with relationships established in the 1980s.
Image: Installation of upstream mitre gate leaf