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WOODSIDE DIVISION 5 Part of a 400-acre master planned residential community, which deeded 300 acres to King County as dedicated open space and developed 100 acres for 474 single-family homes. Division 5 was one division of the total of six in which Sajasa participated during the entire build-out of the new community. Spot Light "Star Wars" rock excavation Problem Division 5, which encompassed a 27-acre 115 residential lot plat, encountered approximately 10,000 CY of rock over a very large area of the Division. The rock quality varied from weathered siltstone to extremely hard rock that, in the geotechnical consultant’s opinion, would require blasting. The permit process for blasting, if allowed, would delay scheduled completion. Solution Test holes were dug with "Star Wars" mounted on our 140,000-pound Cat 245 excavator to identify rock location, quality and quantity. “Star Wars” is a special earth mover application with five rippers mounted on the back of a tough rock bucket. To our knowledge, it is the only one in the Northwest. A planned sequence was developed to facilitate trench excavation with minimal delay to pipe laying operations. In areas of extremely hard rock, "Star Wars" was utilized in tandem with a 10,000 ft-lb Rammer hydraulic breaker mounted on a 95,000-pound Hitachi EX450 excavator to pre-dig rock in advance of utility installation. In areas of less competent rock that could be dug without significant delay, the Cat 245 with "Star Wars" was used on it's own. Results Although the rock excavation added nearly 2 months of additional excavation time, the original schedule was met, because a thorough assessment of the rock and related schedule impact had been performed. This allowed Sajasa to utilize the right equipment and sequence the work to optimize the production schedule. Acknowledgements
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