Alexan Arapahoe Square

Alexan Arapahoe Square

This 13 story , 355 unit apartment building includes 8 stories of living units constructed using the Prescient™ framing system over 5 stories of parking constructed with a cast-in-place concrete structure. The 6th floor post-tensioned concrete podium slab capping the concrete portion of the structure was designed to accommodate and transition the non-stacking gravity and lateral loads from the Prescient™ framing system above to the cast-in-place structure below. The podium level also provides support for outdoor amenity spaces including a swimming pool and courtyards complete with outdoor kitchens, pergolas, and many planters.  The depth of bedrock below the building presented a challenge for supporting a building of this size. Bedrock at the project site was determined to be approximately 70 feet below grade making construction of a conventional drilled pier foundation cost prohibitive. At this depth, each pier would require casing for groundwater and collapsing sandy soils, as well as excessive time and material for construction.  To solve this issue, additional soil testing to justify a higher allowable bearing pressure was ordered and a grade-level cast-in-place shallow mat slab foundation was designed to support the heavy loads of this mid-rise structure. This project was designed in coordination with Kephart Architects for Trammel Crow Residential.