J. Matthews, A. Crichton, G. Gibson
Glenmaggie Dam is a 37m high concrete gravity dam, which was constructed from 1919 to 1927. A
design review, which was carried out in line with ANCOLD Guidelines, (SMEC 1999) indicated that the dam did not meet the ANCOLD Guidelines for earthquake. This was despite the fact that the dam was stabilised in 1989 by the addition of 70 post-tensioned ground anchors. Faced with the possibility of having to perform a major upgrade to the dam, Southern Rural Water opted to undertake a more detailed assessment of the seismic loads and to carry out further analysis of the dam using the time history method. The time history method uses an accelerogram to model the forces acting on the structure throughout the earthquake and takes into account the continually changing direction of these forces. It can also be used to determine the size of any permanent
displacements caused by the earthquake, which can then be compared to the maximum allowable permanent deformation of the dam to determine if they are acceptable. The study was carried out by GHD Pty Ltd and also utilised updated seismic information for the dam site provided by the Seismology Research Centre and a geological assessment of the local faults by the URS Corporation. This paper discusses the methods used to determine the seismic loads; the techniques used in the study and the outcomes and follows the process from a dam owner’s perspective.
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H. Morrison, J. Leckie, P. Richardson, R Paton
Awoonga Dam is a 40 metre high concrete faced rockfill dam on the Boyne River near Gladstone in Central Queensland. The dam supplies domestic and industrial water to the Gladstone region and the Callide Power Station. Stage 1 will increase FSL by 10 metres to EL 40, which increases storage capacity from 289,000 ML to 777,000 ML. To provide for future industrial growth in the region, the dam design facilitates future raising up to a nominated FSL of EL 62, in a number of stages.
The project consists of:
Significant savings were realised by adopting the alliances project delivery method, resulting in completion 5 months ahead of program and more than 10% under budget.
This paper details development of the project under the alliance and outlines some of the lessons learnt.
D.S. Bowles and Loren R Anderson
Starting a quarrel is like breaching a dam; so drop the matter before a dispute breaks out. Proverbs 17:14 (NIV)
An approach is summarised for presenting the outcomes of traditional engineering assessments and risk assessments to inform non-technical decision makers. The decision justification approach can be adapted to any dam owner’s unique decision context. It includes rating systems for presenting the outcomes from engineering assessments and from applying tolerable risk criteria, including ALARP. Three decision types are addressed: setting tolerable risk goals for individual dams, identifying a risk reduction pathway for a portfolio of dams, and managing residual risk on an on-going basis
Russell Hawken, Peter Buchanan, Doug Connors, Bill Hakin
Dartmouth Regulating Dam is located on the Mitta Mitta River, approximately 8 km downstream of
Dartmouth Dam. The dam is a 23 m high concrete gravity structure with a 60 m long central spillway
section. The dam forms the storage required for regulating releases from the Dartmouth Power
Station back to the Mitta Mitta River, so as to satisfy environmental requirements. Dartmouth
Regulating Dam and Power Station are owned and operated by Southern Hydro Limited, the largest
hydropower generator in Victoria.
To allow greater flexibility in their generation and hence a better response to the peaks in electricity
demand, Southern Hydro investigated the possibility of increasing the full supply level of the dam.
After an initial assessment of the economic benefits a detailed review of raising options was
undertaken, including different proprietary products and conventional spillway gates. Following this
review it was concluded that the Hydroplus System would provide the greatest benefits when all
aspects of the raising were considered, including dam safety, long term reliability, maintenance and
This paper discusses the reasons for the raising of the full supply level, the approvals process
undertaken and the technical issues addressed during the design stage, including the required
modifications to the dam and the appropriate sizing of the Hydroplus Fusegates.
Following the construction of the Snowy Mountains Hydro-Electric Scheme, flows in the Snowy River have been reduced to 1% of their original level at Lake Jindabyne. The Victorian, NSW and Commonwealth Governments have agreed to restore 212 gigalitres per annum (about 21% flows) to the river over a ten-year period and 28% in the longer term. The increased flows will be sourced primarily through water savings projects in Northern Victoria and NSW. This is a case study in learning how to share our precious water resources between environmental, social and economic needs.
R.M. Dawson, A. Orange
Karapiro dam is the last in a line of hydro-electric dams on the Waikato River, in New Zealand’s North Island. Investigations identified a potential deficiency in parts of the dam under seismic loading. Detailed investigations and analysis narrowed the deficiency to a low strength clay seam under the concrete gravity left abutment structure. An innovative approach was taken to solving the stability problems at minimum cost, without lowering the storage lake, which would have had significant environmental and social impacts. The process of design and construction was overviewed by an international board of review.
Construction was completed in three main stages with further investigation and design refinement between. The main contract was completed over about eight months and included detailed concrete mix and pour schedule design to control stress development due to temperature gradients for the 2000 + cubic metres of mass concrete placed. While the extent of work was relatively small, the quality control, programming, and presence of a full reservoir throughout demanded a high degree of communication and co-operation between the Principal, Designer and Constructor. Despite some surprises during construction, the project was completed within budget and formed strong bonds between all those involved. This paper briefly describes the design process, and focuses on construction, from the point of view of the Owner, Constructor and the Designer.