Client: Alliance Residential Company
Completion Date: 2009
Services:  Existing Structures, Condition Assessment

Summary:

J.R. Harris & Company provided structural engineering services for the vertical expansion and adaptive reuse of the historic Piggly Wiggly Building, now known as TwentyOne 01 Market and formerly Broadstone Lofts, located at the corner of 21st and Market Street in Downtown Denver. Originally constructed in the early 1920s, with a third story added later, the warehouse-style building features a mild reinforced concrete flat slab system with drop panels supported by octagonal columns with capitals, and cast-in-place concrete spread footings. To support the building's transformation into a six-story apartment complex, JRH performed a structural condition assessment of the existing frame and foundations to evaluate their capacity to support three new post-tensioned concrete floors above.

Following the assessment, JRH provided full structural design services for the new construction, including the design of post-tensioned concrete floor systems, new concrete columns, and concrete elevator core walls. The project also required the design of new foundation elements to accommodate wall penetrations at the basement level, allowing for access to a new adjacent parking garage. Construction phase services were also provided to support the successful execution of the additions and modifications to the existing structure.