Howard Hanson Dam Additional Water Supply Project - Fish Passage Facility Reaction Plane Strengthening, King County, Washington

Howard Hanson Dam (HHD) is located on the Green River in western Washington and is a 230-foot-high rock fill dam. The existing outlet tunnel is 900 ft long, with a 19 ft semi-horseshoe shaped cross section, which is concrete lined. A Fish Passage F acility is being constructed adjacent to the existing outlet tower and outlet tunnel. To date, the excavation has progressed from elevation 1150 to 1074 feet and the front section of the Fish Passage Facility has been constructed and is being used as cof ferdam to keep the excavation separated from the reservoir. This work includes rock excavation, slope support, and slope stability instrumentation in accordance with contract drawings and specifications. Work shall be undertaken to excavate, through blas ting or mechanical methods, two discrete rock columns from existing excavation slopes. Rock columns are 12 feet x 60 feet x 76 feet high and 3 feet x 6 feet x 65 feet high of intact rock, respectively. Both rock columns are immediately adjacent to existi ng dam structures which must be protected from damage associated with excavation operations. Exposed faces on both columns are currently supported with #9 and #11 rock dowels (passive) and six inches of fiber reinforced shotcrete. The larger column is al so capped by a six inch concrete slab. Both the existing reinforcement and concrete slab will be demolished as part of the rock excavation. Freshly exposed rock slopes shall be supported with shotcrete, welded wire fabric, reinforced shotcrete grade beam s, and post tensioned rock anchors. Slope support shall be installed in 10 foot lifts as the excavation progresses. Slope stability instrumentation shall be installed both before excavation commences and concurrently with excavation. Instrumentation inc ludes a piezometer, an inclinometer, and three multipoint borehole extensometers.
Project is open to both large and small business. The North American Industry Classification System (NAICS) Code is 237990 with a size standard of $31million. For the purposes of this procurement, a firm is a small business if its annual average gross revenue, taken for the last 3 fiscal years, does not exceed $31million. For information concerning NAICS and SBA size standards, go to http://www.sba.g ov/. Issue of th e solicitation will be in electronic format only. No disks or hard copy will be available. Follow the registration procedures at this site to receive notification of solicitation/amendment posting. Pursuant to Federal Acquisition Regula tions (FAR), the solicitation will be available for download no earlier than 15 days following the posting of this synopsis. There is no technical information available until the issue of the solicitation via the Internet.