Weight distribution is another engineering challenge because of the density of the books and the shifting loads that occur when they are moved throughout the stacks from time to time. An average book weighs about 12 ounces. The San Diego Public Library houses about 2.8 million books throughout its system. The central library has the biggest and heaviest collection.
The library is designed to accommodate more than 1.2 million books, reference documents and other materials.
WEIGHTY TOMES
To deal with the problem of weight distribution, the engineer designed special columns and flooring for the building's structural concrete frame. The columns are smaller than is typical for office use, but they contain significantly more reinforcing steel. The rounded columns, which have a range in size and diameter, are reinforced with No. 18 rebar. Each column has 19 tons of rebar per lift—from the top of one slab to the bottom of another.
Waffle slabs—concrete slabs that resemble waffles on their lower surface to increase strength in both directions—are used in the flooring. “If you went into parking structures years ago, you'd see the indented waffle slabs overhead,” Vann says. “The slabs are actually formed in large waffle-like pans to create the gaps.”
Waffle slabs for all areas in the library that might house books are designed for a minimum of 150 psf live load.
The building team is aiming for LEED certification from the U.S. Green Building Council's rating system called Leadership in Energy and Environmental Design.
Green features include solar photovoltaic panels to produce electricity, water-efficient landscaping and an overall water-use reduction of 40% from state standards. More than 50% of all site waste is being diverted from landfills for recycling, while adhesives and paints contain no volatile organic compounds. SC Engineers is the mechanical consultant, and LSW Engineers is the electrical consultant. Both of the firms are based in San Diego.
FUNDING MIX
The library is being financed largely through a state library grant, state and city redevelopment funds, private donations—including a $20-million pledge from Qualcomm founder Irwin Jacobs—and $20 million from the San Diego Unified School District to lease space for a charter school. San Diego taxpayers might have to cover about $35 million, says Quigley.
The final product will have free Wi-Fi access and 500 parking spaces, including 250 across the street and 250 more in a 129,000-sq-ft, underground garage. The 76,000-sq-ft charter high school will occupy the building's sixth and seventh floors.
The project is located in San Diego's up-and-coming East Village neighborhood, near Petco Park, the home of the San Diego Padres.
