DBM Completes Excavation Support at Fred Hutchinson Cancer Research Center Phase IV - Public Health Sciences Building

Job Location: Fred Hutchinson Cancer Research Center Phase 4A, Seattle, WA

Project Owner: Fred Hutchinson Cancer Research Center

Project Description: DBM Contractors, Inc. recently completed the excavation support for the continuing expansion of the Fred Hutchinson Cancer Research Center. The project site for the new Phase IV – Public Health Sciences Building comprises a full city block adjacent to the existing FHCRC facilities. When complete in the winter of 2003 the five story structure will include 360,000 square feet of new offices and research labs as well as three levels of underground parking.

DBM has recently completed shoring for the 48 foot deep excavation under contract with Turner Construction Company. DBM’s $2.3 million contract included installing 300 soldier piles/secant piles, more than 500 permanent and temporary tieback anchors, and approximately 34,000 square feet of timber lagging. During design of the shoring system challenges included providing more than 11,000 square feet of “permanent” excavation support and a secant pile cutoff wall. The “permanent” excavation support installed at the east end of the project site is designed to withstand lateral earth pressure to accommodate construction of a future expansion. The system also includes a 475 foot-long secant pile cutoff wall along the Lake Union side of the project. The secant wall required installation of 99 structurally reinforced piles 36 inches in diameter and 98 lean concrete 36-inch diameter infill piles. DBM also installed 32 five-foot diameter drilled shafts averaging 55 feet deep to provide foundation support for the new structure. Site conditions that included remnants of foundations from previous structures, areas of contaminated materials, and areas of glass backfill from previous construction activities contributed to the complexity of the excavation support system.

Other team members include: CTI, Inc., excavation contractor; Zimmer Gunsal Frasca Partnership, architect; KPFF Consulting Engineers, civil engineers; and URS Corporation, geotechnical engineer.

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