Registration is free - RSVPs are due May 6 for lunch
Presentation Title: Block 76 (City Creek Center) Excavation Support and Lessons Learned
Presenter: Rick Deschamps, Ph.D., P.E., vice president of Nicholson Construction Company
The City Creek Center Block 76 Project included the demolition and redevelopment of an entire city block for mixed use retail, office and residential properties directly adjacent to Historic Temple Square in Salt Lake City, Utah. Excavation was carried out 65 ft below street grade and as much as 50 ft directly below adjacent buildings supported by shallow foundations. Movements of the earth retention system and adjacent buildings were monitored in real time using automated equipment which complemented the traditional suite of geotechnical instrumentation. In the areas immediately adjacent to the existing buildings greater than 10 stories, anchored diaphragm walls were employed. Areas of the site not supported by diaphragm walls used a soil nail wall system. Jet grouting was used as an alternate for water cutoff in lieu of dewatering to mitigate water inflow along the North and East sides of project. In total, the earth retention scope included 45,000 sq. ft of diaphragm wall, 104,000 sq. ft of soil nail wall, micropile underpinning of three buildings, and high capacity auger cast pile foundations. This paper provides an overall description of the Block 76 project. A detailed account is provided of the technical and commercial lessons learned. The project provided a unique example of how an owner can receive best overall value by accepting some technical risk up front. Benefit was gained by allowing the contractor to reduce contingencies within the bid from unknowns on a fast-track project.
