Trial mix programme and full-scale trials for Olivenhain RCC dam, USA

The RCC placement at Olivenhain dam was successfully completed in October 2002 in the USA. Some 900,000 m 3 of RCC was placed in seven months making it one of the fastest RCC dams so far constructed. The dam is a straight-gravity structure, 97 m high and 778 m long and is part of the San Diego County Water Authority's Emergency Storage Project for the San Diego region of California to provide water for the area in the event of a severe earthquake or drought. An extensive trial mix programme was conducted by the Contractor, Kiewit Pacific Co., in parallel with that being undertaken by the Designer, to try to simplify the method of construction. In addition, prior to the start of placement of the RCC in the critical dam section in the main valley, a series of full-scale trials were constructed in different parts of the Project. The paper describes the objectives of the different stages of the trial mix programme. Details of the construction of the different full-scale trials are also included as are details of the training programmes developed for the different activities associated with the RCC method of construction. The quantity of RCC placed at Olivenhain in full-scale trials, prior to start placing RCC in the main dam, was considerably more than usual. Rather than this being initially planned, the main reason was the design of the dam itself, which included two shaping blocks as replacement for poor foundations. These were utilised as full-scale trials. Nevertheless, the paper shows that the trials were an excellent opportunity to allow all of those involved with the construction of the dam to get some way up the "learning curve" before the start of RCC placement in the main dam body.