This 902,000-gsf concrete structure includes a 17-story residential tower containing more than 500 residential units. The design also called for constructing and connecting the building’s three basement levels to those of an adjacent residential building to create large floor plates of parking. But with the site’s water table just 18 ft below grade, creating 65-ft-deep structural connections would require breaking waterproofing seals to cut new vehicle access openings in the existing building, then restoring the waterproofing measures.

The project team developed a system of below-grade expansion joints, incidental water mitigation drains, and other measures to create dry, structurally sound spaces for the garages. The team also applied its construction ingenuity to install a large glass-clad escalator with no center support to connect the 35-ft-deep below-grade grocery store level to the street-level grand entrance. Because the escalator was too heavy for a tower crane, the team added reinforcement to the structural slab above to support air tuggers that hoisted and set the escalator.

BIM, laser scanning and other technology tools played key role in coordinating 1177 Market Street’s many features, and increasing installation efficiency while also lowering costs. They include an 80-ft-tall open-air portal connecting the busy Market Street thoroughfare to the building’s interior plaza that was constructed by formwork tables supported from the building’s columns with no temporary supports down to grade. Even the complex round marble benches imported from Italy were carefully modeled to ensure the correct support substrate was in place prior to their arrival.