A public library is a symbol of equality and opportunity. Its doors are open to everyone; its contents free to all who want to learn. Many major cities across the United States count their public libraries as a centerpiece to their architectural character, and for many people a visit to the library may be their first introduction to architecture. The new San Diego Central Library is an example of one of these inspirational architectural centerpieces open to everyone.
The 504,000-square-foot building has two levels of underground parking and nine above-ground occupied floors to house 1.25 million books, 400 public computers, meeting rooms, study areas, gallery space, a 400-student charter school on two floors, central offices to serve the 35-branch library system, and a nearly 4,000-square-foot reading room enclosed with three-story-high concrete, glass and steel walls. The library building includes 28,000 cubic yards of structural, cast-in-place architectural concrete and an additional 15,000 cubic yards of non-architectural structural concrete.
Concrete work on the building is just winding down, and the new library will open to the public in July 2013. Concrete subcontractor on the project was Morley Construction Company’s concrete group out of San Diego, Calif. Morley spent nearly 18 months on site, averaging 70 employees on the job.
The project is an epic accomplishment in concrete construction. Unique elements include roof cantilevers exceeding 11 feet, hybrid structural systems, 6-foot-square and larger mass concrete columns, and a 46-foot-tall and 70-foot-wide concrete gravity arch. “Even the guys who have been at Morley a long time refer to it as a landmark project in their careers,” shares Sean Fleming, project manager with Morley Construction Company. “It will be an iconic structure for the city, and its domed silhouette is sure to become a signature of the San Diego skyline.”
Getting the job
Planning for the new library began in 1995, when the city of San Diego began earmarking the funds it needed to replace its 1950s-era main library to serve the city’s growing population. The city hired architect Rob Wellington Quigley to design a building that would serve not only as a shelter for books but a community gathering space and architectural focal point for the downtown area. Over the next 15 years the city and non-profit enthusiast groups garnered the $185 million needed for construction while plans were completed and permitted. In 2010 Turner was hired on as general contractor and initiated the bidding process for a concrete subcontractor and other trades.
Turner utilized a best value bidding process to award all trades in the public bid. Morley was one of eight prequalified concrete subcontractors to submit a proposal. Different aspects of the project bid were weighed, including 50 percent for price, 30 percent for relative experience, and 5 percent each for categories of EMR rating, small business and local participation, company stability, and management team experience. “Morley’s combination of competitive pricing and high marks in team experience, safety record and small business partnering secured the award,” Fleming says.
An open structure
The library was structurally designed to provide open floor plans throughout the building with lots of natural daylighting. “As you walk the floors of the library, for instance through where the stacks will be, there is very little interruption of the space,” Fleming says. “Even though you’re in this expansive concrete structure, what might appear imposing on the plans is in fact open and airy.”
This open effect was achieved through the use of Special Moment-Resisting Frame (SMRF) concrete beams and columns incorporated with conventional waffle slab floor plates, which all but eliminated the need for shear walls throughout the building. Typical SMRF beams are upturned 5 feet deep by 27 inches wide, while the SMRF columns range in size, up to 75 inches square. The SMRF beams and columns are located along the structure’s perimeter to create rigidity in the planes of the building facades. This design strategy allows the interior of the library to be supported by much smaller gravity columns, only 30 inches square.