At the Metropolitan twin towers in San Francisco, the architects wanted to balance the use of glass with a masonry-like material that could be textured. Cost limitations were a key client parameter, which Clark Pacific precast was able to accomodate.

Clark Pacific teamed up with Heller Manus to design and build multi-planed panels. Some panels spanned a distance of 15 feet, made a right angle return for 3 feet, and then extended at another right angle for 5 to 15 feet more. This allowed us to make one piece in place of two or three. A typical flat panel was 4 inches thick by 10'6" tall and 30 feet long with punched window openings.

Approximately 200 of the building's 595 precast panels were multi-planed which allowed the team to shave $300,000 off the cost of building the structure. The budget was very tight but with a brilliant design strategy, Clark Pacific was able to bring the project in on budget.

Seismic concerns also required that the panels to be as light as possible, creating minimal dead loads on the structure. The thin panels were prone to break, which created handling challenges for the project. It required a special rigging for lifting and erection. It took considerable engineering ingenuity on Clark Pacific's part to figure out how to remove the multi-planed panels from their forms, transport and erect them without breaking the pieces.

Not only does the precast turn corners in a multi-planed panel, but the windows do as well. Normally a post would be designed at the corners, but Clark Pacific used a thin mullion which helped to save a lot of caulking. Panel systems, with windows in place, were tested under simulated seismic loads in a full-scale mockup. In an earthquake, the building can drift 4 to 6 inches from floor to floor. With connections performed properly, windows will not pop out.

The beauty of the precast panels along with the confined structural elements at the core of the towers, helped to maximize the scenic views from the towers and create a grandeur that is indicative of San Francisco.