5035 Coliseum is a mixed-use development highlighting how large-format retail and high-density residential living can coexist in a dense urban context. Located in Los Angeles, CA, the project delivers 800 purpose-built rental units above a ground-level Costco warehouse, which is supported by five levels of below-grade parking. The development posed unique structural challenges, each requiring innovative performance-driven solutions to balance functionality, constructability, and cost.
To accommodate Costco’s large-format retail floorplate, the structure demanded unconventional 40-foot column grids, deviating from the typical 30-foot spans used in residential construction. Costco’s specifications require very heavy loading and stringent deflection requirements for the tall storage racks in their warehouse. Our team addressed this challenge with a post-tensioned slab system at the below grade and above grade podium levels. This allowed for the required long spans without compromising constructability.
The integration of heavy retail loading and stringent deflection requirements added further complexity to the structural design. Working with these constraints, we developed a robust solution that replaced an earlier deep-beam system with a thicker flat slab supported by elongated below grade columns. This design met Costco’s performance standards, but also reduced excavation depth by over two feet, leading to substantial savings in shoring, foundations, and basement wall construction.
With under four months to complete a full redesign and secure City approvals, our team collaborated closely with the City plan checker and project expediter. The result was a clear, coordinated structural submission approved on first review, keeping the project on schedule and moving forward.