Microsoft West Campus Parking Structure

Location: Redmond

Owner/developer: Microsoft

Project team: GLY Construction, general and concrete contractor; Callison, architect; ABKJ, structural engineer; Cadman, ready-mix supplier

Microsoft’s West Campus Parking Garage, at 1.6 million square feet, reportedly is the second largest underground parking garage in the United States. Its four levels contain 4,637 parking stalls.

Microsoft originally envisioned an above-ground parking garage, but decided to put it underground and top it with a 10-acre green roof with sports fields and a three-building complex containing retail space and offices. The buildings total 156,500 square feet.

The concrete for the garage, 75,755 cubic yards, was poured daily for 10 months. The accelerated deck pours resulted in up to 100,000 square feet of new concrete surface a week.

The garage’s framing consists of a modified Cunningham system with 60-foot spans, post-tensioned beams spaced 25 feet on-center and post-tensioned slabs. Using concrete allowed the design team to reduce the number of interior columns, thus improving user visibility. Concrete also reflects light better than fireproofed steel ceilings, making the garage brighter to its users.

Using concrete allowed the garage to be divided into several independent structures to address long-term shrinkage and durability issues.

The project is targeting LEED silver certification.