Morley designed random plywood patterns for every column form including the various “block-out kits” inset within the column forms to create T- and L-shaped columns. Also employing the random pattern design requirement were the walls, exterior beams, exposed decks and concrete gravity arch. Plywood sheets were cut to 4x4 and 3x6 or smaller and arranged to create a random pattern. “It was a request we had never done before and many thought it couldn’t be done. I took it as a challenge and personally designed nearly every pattern you see on the job. I started with the columns and walls and moved on to the gravity arch. The end result truly looks random, but it all had to be preplanned,” Fleming says. “We came up with elaborate coding plans for the plywood layouts, almost like a paint-by-number drawing, to identify pieces so they could be pre-cut and assembled in the correct order on the jobsite.”
Because this project had a large number of column types, Fleming created a column numbering system and floor-by-floor column placing plan to streamline the column forming process. “One column form could be responsible for creating six different shapes, so we had to minimize the handling,” he says.
Every column type was coded by color and given a designation by letter and sometimes number as well to identify the shape and any kits required to modify the shapes. The forming crews then had precise direction on column placement order. Since column forms were to be reused from bay to bay, instructions were given specifying the orientation the column was to be turned to achieve an even higher degree of randomness.
The forms were all double-layered plywood and backscrewed, or finish nailed, with the first layer a shop-grade and the fascia layer being Olympic Panel’s Barrier Film, a white malamine overlaid plywood. “There was no water absorption into the face of the panel so it gave us a bright color when compared side-by-side with other architectural-grade plywood products,” Fleming says about the decision to use the Barrier Film product.
Morley pushed the boundaries on the tie hole pattern in the columns, too. With 15-foot spacing between the floors and the architect’s request for a uniform appearance in the tie pattern, Morley needed spacing that would be divisible by 15. Three-foot spacing was too tight for the architect, so they pushed form tie spacing to 5 feet on center. “We challenged a lot of our vendors with that request, but we found ways to make it work, such as increasing the size and reducing spacing of walers and utilizing lots of dry ties,” Fleming says.
Morley crews applied the same random pattern styling to exposed beams, walls and the gravity arch. “Getting the random pattern in the arch was challenging because we were working with square seams in a curved form and had to figure out how to line up tie holes and keep them at least 12 inches from a seam,” Fleming explains.
The result was worth the effort. “It really is a special effect of sorts when you look at it,” Fleming says. “With so much of the architectural concrete in the world today you can immediately see a distinct pattern in the tie holes, lines and seams, and your eye automatically follows those man-made patterns. But because this building has so many random seams everywhere, when you look at it your eye moves constantly. Rather than appearing mechanical, it looks organic.”
As the concrete work on the library project winds down, it’s evident that the architect’s vision for a structure that will serve as a centerpiece to the city’s character and community activity has come to life. And it’s a building that embraces its construction and materials.
“The design allows for everyone to see the way the building is built, that is to say that the materials used to build it and various components used to make the building run and function are visibly expressed, not hidden. It’s honest to the trades, and being builders we can really appreciate that,” Fleming says.
That means exposed steel, mechanicals, and design and structural elements composed of concrete both inside and out. It proves the San Diego Central Library is not only a centerpiece for the city, but also a concrete structure that serves as an example of the opportunities cast-in-place concrete can offer the architectural design community.
San Diego Central Library
Concrete contractor: Morley Construction Company, San Diego, Calif.
General contractor: Turner Construction Company
Design Architect: Rob Wellington Quigley, San Diego