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$35M Project Protects UCSD Centerpiece from Earthquakes

CONSTRUCTION: York Hall Seismic Retrofit to be Completed in Fall

A $35 million project to strengthen one of the oldest buildings on the University of California San Diego’s Torrey Pines campus to protect it from earthquakes is wrapping up with completion expected in the fall.

Built in 1966 in the Revelle College neighborhood of UC San Diego, the 134,000-square-foot York Hall was one of the original structures on campus and is a centerpiece of the university.

Bryan Seamer
Director, Structural Engineering
LPA, Inc.

“It’s a really heavily used building that’s booked from early in the morning until late at night,” said Bryan Seamer, director of structural engineering at LPA, an Irving engineering company that designed the project.

Consisting of four connected buildings, York Hall also “is the heart of our campus,” said Elisa Pittner, UC San Diego project manager.

Elisa Pittner
Project Manager
University of California San Diego

Although not listed on an historic register, York Hall “contributes to the historic character of our campus,” Pittner said. “We do select architects and designers, who propose how they would do this without interfering with that historic character, not just the building, but the overall Revelle College character.”

Work on the project began in 2020, and this year, it received awards from the Structural Engineering Association of San Diego and the Structural Engineering Association of Southern California, an industry trade group.

‘An Elephant on Chicken Legs’

With 36 elaborate, ornate columns, including four that needed to be completely rebuilt using steel rebar wire and fiberglass molds, and with masonry walls that weren’t designed to withstand a major quake, the seismic retrofit proved especially challenging.

“The more significant and challenging part of the retrofit was that the western wing of York Hall is a very unique design where there’s these two stories of classroom space above an exterior arcade with these really striking, beautiful columns,” Seamer said. “It’s really this iconic piece of architecture on campus. There’s a lot of stress on those columns to be able to resist an earthquake trying to shake the whole building back and forth.”

Seamer said that the four ornate columns that had to be rebuilt weren’t designed to absorb rocking motions that would occur in the upper parts of the building during an earthquake.

Consider the building to be like “an elephant standing on chicken legs” and how hard it would be for that elephant to stay standing, Seamer said. “The geometry of those columns is unique.”

To recreate the look, molds were cast of the four existing columns to be replaced, then taken to a boat manufacturer to make fiberglass forms, said Michael Gibbons, construction project manager of PCL Services, the general contractor.

Michael Gibbons
Construction Project Manager
PCL Services

“We basically cast a mold of the existing column on the building and essentially, like paper mâché, took that mold off and then took it down to the boat manufacturer where they were able to fiberglass it,” Gibbons said. “Then it was reinforced to withstand the loads of the concrete, finished up and shipped to the job site where it was bolted into place.”

At the same time, steel skeletons were put in place of the old columns, which were demolished. The fiberglass forms were bolted to the steel skeletons, which were filled with fresh concrete poured through holes that were drilled in the floor, Gibbons said.

While the new columns were being made, the building was supported by temporary foundations.

Seamer said that typically, the column forms would be made of wood, but that wouldn’t work in this case because of the flared design of the columns.

In addition to the columns, York Hall is ringed with what Seamer described as vertical fins that needed attention because they had deteriorated in the salt air environment of the campus.

“We developed a menu of different types of repairs to the body of the fins, to the base, the top, and the connection to make sure that they’re robustly tied to the buildings for generations so there’s no risk of them falling,” Seamer said.

Part of the work also involved adding concrete shear walls in part of the building by projecting wet concrete against steel rebar webbing in front of existing walls made of six-inch to eight-inch masonry blocks.

“We added somewhere between 6 to 8 inches, on average, or new concrete directly adjacent to those original walls,” Seamer said.

In addition to the seismic retrofit of the overall York Hall building, a number of deferred maintenance projects were included.

Among them was adding a new roof to the York Hall auditorium, repaving an exterior plaza, and waterproofing much of the roof.

“The hardest part of the job was really just coordinating the work in an occupied building,” Gibbons said.

UC SAN DIEGO

Established: 1960
Campus: La Jolla
Chancellor: Pradeep Khosla
Business: higher education, research and healthcare
Enrollment: 43,000
Website: www.ucsd.edu
Contact: 858-534-2230
Notable: UC San Diego is ranked among the best public research universities in the world.

Despite the challenge to replicating them, York Hall’s unique columns remain true to their original design. Photo courtesy UC San Diego
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