The Colorado Convention Center Expansion project is a 1.4 million square foot expansion of the existing facility. This was a multi-level project, which included a 1,000-car attached parking garage. The light rail and street that ran past the existing building had to be relocated to run under the new structure - directly beneath the parking garage and truck loading dock. There is also a passenger loading/unloading area and a station for the rail line under the garage.

The garage above the street was constructed using precast tees and columns with a cast-in-place topping slab. In order to maintain regular spacing for the columns in the precast section of the garage and still maintain an unobstructed path for the road and light rail, large post-tensioned transfer girders were required to support several of the columns above. The transfer girders allowed for the placement of columns required for the precast design despite the restricted column locations at the street level. Post-tensioning the transfer girders resulted in smaller dimensions than a conventional reinforced concrete design, an important factor given the girders are over 7 feet high and up to 7 feet wide and a larger section would not fit within the space constraints of the building. The girders could not be stressed until after the precast garage was fully erected and the topping slab poured on the truck dock. Temporary columns were placed under the girders to support the load until stressing.

The effective post-tensioning force required for the beams ranged from 2176 to 5457 kips. A multistrand bonded post-tensioning system was installed, utilizing the VSL ES5-19 and ES5-31 anchorage systems with galvanized duct. One significant challenge was the placement of the anchorages, such that stressing access could be obtained after the precast tees were in place. This was compounded by the fact that the slab above had to be in place before stressing could occur. In order to accomplish this, the anchorage placement was closely coordinated with the precast supplier to ensure that no conflicts occurred between the anchorage assemblies and the precast support embeds or the stressing ram and the tees themselves. A slot was blocked out in the slab above to provide access to support the ram during stressing. This configuration allowed two crews to stress the beams after the precast had been fully erected.