Spotlight |
The design and tender phase Harza got some good news during the 15th ICOLD
Congress in Lausanne Switzerland in Mid-1985 as the head of the Chinese Delegation, Vice Premier, Li Edin informed Dr. Yeh they wanted Harza to do consulting work on the Ertan Project. Importantly CHIDI accepted the general layout that Harza had suggested with an underground powerhouse and thin arch dam, which departed from the original scheme of a gravity arch dam and powerhouse at the toe of the dam. The negotiation proceeded in 1986 with a proposal and work scope involving all the project’s major features including the arch dam and powerhouse design, hydraulics and geological aspects and rock mechanics, together with construction considerations. After significant back and forth in the negotiation of the scope of work, agreement was reached with Dr Eugene Chang (Geotechnical Engineer), and Dr. Yeh (arch dam) representing Harza in the negotiation. Of importance to reaching an agreement for the design phase of the work was the prior team building engagements between Chinese and US counterparts, who worked through the feasibility work on a side-by- side basis to a common end goal. The contract was signed by Dr. Chang seven years after Wengler’s first trip to China in 1979. The team building continued during the design phase as engineers from CHIDI came to Chicago to meet with counterpart engineers at Harza, with each guest from the client being provided with office space. One of the most interesting exercises that occurred was the iterative design development on the arch dam along with other project features. Briefly, the dam design evolved to a parabolic arch dam with the base thickness being reduced from 71m to 57m with a corresponding volume of the dam being reduced from 4.79 Mm3 3.83Mm3 1Mmm3
to , thus reducing concrete volume by almost
. The reduction in dam thickness reduced the construction period by one year. Professor Zhang Guangdou of Qinghua University
said to Dr. Yeh that: “the stress analysis of arch dam is a science. The design is an art. And therefore, you are an artist.” Dr Yeh noted that was the first and only time he was called an artist.
Stephen O. Simmons
By the end of 1986, the design of the Ertan Project was complete for tender documents. The overall project layout was accomplished for all the major project features. Harza was then awarded a second contract to help prepare the tender document which was needed to meet World Bank terms for a loan along with the World Bank requirement for international bidding. As part of the exchange and work, three key individuals from Harza, including Dr. Jan Veltrop, Harza’s Chief Engineer (member National Academy of Engineering; President of ICOLD 1988-1991), Dr. Eugene Chang and Ken Leonardson went to Chengdu and stayed for six months working with CHIDI’s designers and draftspersons to prepare contract level drawings, quantities and cost estimates, and specifications sections. Other engineers from Harza joined them periodically to contribute to the development of contract documents. The process was tedious, with all documents going through an internal review by the Chinese government including presentation of a report of all the findings to the Ministry of HydroPower Industry.
12 | February 2025 |
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The construction phase Following the review, the World Bank loan application was
initiated with construction starting in 1991 and ending in 1999. During construction, a Joint Venture of Harza and the Advisory Group of Norway provided support as foreign advisors with 10-20 engineers on-site for the eight-year construction period. There were two boards of experts, one of international experts and the other of domestic experts, along with a Dispute Review Board for resolving disputes between the owner and contractors. Construction was divided into two lots, with Lot 1 being above ground construction and Lot 2 being underground work. With construction underway, the thoroughness of the CHIDI underground exploration programme during the design phase led to the discovery of no major faults or joints during foundation excavation. Construction proceeded smoothly, thanks to the completeness of the CHIDI work.
Successful resolution During construction, one example of a successful
resolution of a genuine problem concerned the diversion tunnel gates in a meeting with project owner, Ertan Hydropower Development Company (EHDC), involving the gates matching the gate slots. The diversion tunnels were 23m wide and the contractor proposed a solution to the dimensional problem of the gates that would have cost US$20M. EHDC, however rejected the contractor’s scheme and produced its own that cost $US200,000. EHDC took responsibility for the solution, thus solving the problem for 1/100 of the initial cost estimate. The scheme worked when implemented. The first 550MW unit went on line in August 1998 while construction continued on the arch dam that was completed in late 1999. Construction continued up to the completion date with claims being processed by the contractor and being resolved by EHDC leading to completion of the project. A dedication by President Jiang Zemin (1993-2003) on one of several visits to the Ertan project demonstrated the importance of this project to economic growth in China. The dedication occurred on 1 December 1999, with many dignitaries from Chengdu and Beijing, along with many reporters to document the completion of this massive project adding 3300MW to the grid. EHDC honored Roman Wengler and Dr. Eugene Chang of Harza as special guests, amongst the dozen or so other members of the Harza team, paying their expenses and recognising their significant contributions to the design of a project with such a profound impact in China.
Construction continues Following Ertan, projects in China reached heights
of 305m for a double curvature thin arch dam at the Jinping-1 Project with 3600MW of installed capacity. Five more arch dams were constructed, all with significantly more installed capacity than Ertan including: Baihetan on the Jinsha River at 289m with 16,000MW installed capacity.
Xiluodu on the Jinsha River at 286m with13,860MW installed capacity.
Wudongde on the Jinsha River at 270m with 10,200MW installed capacity.
Xiaowan on the Lanchang River at 292m with 4200MW installed capacity. Laxiwa on the Yellow River at 250m with 4200MW installed capacity.
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