New Hospital Tower in a complex environment-PPT Presentation

PPT Presentation

Pdf Summary

The UW-Hospital D2 Expansion required a permanent earth-retention system for a three-sided excavation while keeping the loading dock functional and the adjacent roadway open. Work was complicated by existing utilities, building footings, a tower-crane foundation, a tunnel, equipment surcharges, and limited staging space.<br /><br />The permanent system reached a maximum cut of 43 feet 6 inches and used drilled soldier piles, temporary wood lagging, permanent concrete facing, and four levels of tiebacks. Design considerations included utility and crane-foundation conflicts, construction surcharges, corrosion protection, insulation, and waterproofing.<br /><br />Temporary systems on the east and west sides had to accommodate additional obstacles, including a skywalk, existing retaining-wall counterforts and piles, a sanitary sewer, and previous construction. Three-dimensional modeling helped identify tieback conflicts. The east-side system used soldier piles, four tieback levels, double-channel walers, and a support buttress wall. Encountered obstructions and changes in force distribution required redesign during construction.<br /><br />On the west side, excavation reached 23 feet. The work combined soil-nail walls with hollow-bar micropiles and underpinning brackets to support existing footings. Vibration, tight corner clearances, and careful sequencing of footing removal and underpinning were important concerns.<br /><br />The presentation emphasizes coordination, responsiveness, and adapting to unforeseen obstacles as essential to successful excavation and support work.

Keywords

earth-retention system

UW-Hospital D2 Expansion

drilled soldier piles

tiebacks

temporary wood lagging

permanent concrete facing

soil-nail walls

micropiles

underpinning

excavation support