Trolley Square Mall
- Location: Salt Lake City, UT
- Owner: Scanlon Kemper Bard Companies
- General Contractor: Okland Construction
- Technique(s) Utilized: Micropiles, Soil Nail Wall
Background
Trolley Square is a shopping center located in Salt Lake City. It is composed of barns that were built in 1908 to house the city’s streetcars. The streetcar system was dismantled in 1945, and the barns were converted into a two-story shopping center in 1972. Trolley Square was registered as a historic site by the state of Utah in 1973. It was added to the National Register of Historic Places in 1996. During 2007-2008, the mall underwent a two-phase renovation project which consisted of 160,000 square feet of commons area, retail space, and landscaping improvements and a second phase of renovations including a new 50,000 square foot anchor-tenant building with underground parking.
The renovations included a seismic retrofit program in which Nicholson designed and installed 18 micropiles at five shear walls inside the operational mall. The micropiles, which were installed to depths of about 40 feet, have design loads of 150 kips in compression and 90 kips in tension. The piles were installed in extremely confined areas with low headroom.
In the separate phase of renovations, Nicholson designed and constructed a soil nail retaining wall system of the existing parking structure. In some areas, the existing outside garage walls were left in place and were included in the design of the shoring system. A new, deeper parking structure was installed within the limits of the existing shored garage structure.
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