Precast Offers Ability to Integrate Enclosure Elements in Off-Site Prefabrication Process

While precast can combine several finishes into one panel, which reduces the need for frequent expansion joints and slip joints to account for differential movement, as well as flashing and other moisture management components, precast concrete can also integrate other materials and systems into it. Precast also affords the opportunity for enclosure integration. Examples include insulation, windows, duct work, electrical, etc. When these types of components are installed at the precast manufacturers facility, it saves time and money while improving safety and quality.

Photo courtesy of © JOSH PARTEE 2014

This project takes system integration and prefabrication to a new level. Precast concrete panels included insulation, pre-glazed punched windows, block outs for louvers, LED lighting conduits, light strips, and plenum boxes - all installed at the precast manufacturing facility and then shipped the project site. The 500 precast concrete panels, with light and medium sand blast finishes, were installed in about 5 months.

CASE STUDY: LA LIVE MARRIOTT HOTEL

Designers of the 23-story, mixed-use LA Live Marriott Hotel in bustling downtown Los Angeles originally envisioned the structure with a metal panel and glass curtain wall facade system. When that solution failed to fit their budget and high-performance demands, the owner and design-build team turned to a local precast concrete producer to come up with a better alternative. The facade had to be cost effective, durable, and able to meet continuous insulation requirements, all while complementing the aesthetic design of the structure.

What emerged was an architectural precast concrete enclosure that features 119,000 square feet (11,100 square meters) of composite architectural precast panels, with 6,000 square feet (560 square meters) of architectural precast concrete on the podium. Panels span floor to floor, with punched window openings of varying widths and spacings with aluminum framing and glass, which were pre-assembled into the precast panels and shipped to the job site as single modular units.

The pre-glazed, pre-insulated panels could then be installed immediately upon arrival at the job site without the need for on-site glazing or insulation subcontractors, resulting in additional schedule and cost savings.

Photo courtesy of DPR Construction Project Team

This project used the versatility of precast concrete to create deep recessed windows, which were installed at the precast concrete manufacturer’s facility, to create sunshades reducing the solar heat gain that occurs in this hot environment. Precast concrete was the only exterior option that offered the design flexibility to yield so many different “shade patterns.” This was achieved through protruding sunshade “boxes” around the window openings that had angles varying from 0-15 degrees horizontally and pitched down as well. The precast concrete received a light sand-blast finish.