Inside an Integrated Design

A multidiscipline team takes on the complex challenges of the seismic retrofit of a historic teaching and research lab facility on the University of California, San Diego campus.

On the University of California, San Diego campus, York Hall plays a special role in the school’s history and culture. Named for Herbert York, a nuclear physicist who served as the university’s founding chancellor, the mid-century complex designed by Neptune & Thomas Associates comprises four buildings serving undergraduate science education. The west building sits atop thin, hexagonal fan-vaulted columns that form a breezeway under the building and fronts the historically recognized Revelle Plaza, the heart of the historic college.

When the university decided in 2022 to retrofit the 57-year-old complex and its iconic column colonnade to meet the University of California’s seismic policy, the project was both badly needed and complicated. York is still a vibrant part of the biology and chemistry department, active daily from 7 a.m. to 10 p.m. In addition to the aging 300-foot-long column arcade, the façade featured 801 precast concrete fins that were deteriorating in the marine salt air.

“The York Hall buildings were very much in need of seismic retrofit,” said Elisa Pittner, who was UC San Diego’s program manager for the York Hall project (and is now the principal project manager at UCLA). “The west building sits atop columns that make it top-heavy and vulnerable to seismic events, thereby requiring reinforcement.”

The story of the York Hall retrofit provides a distinct example of integrated design at work. The process required engineers, architects, landscape architects, designers, the contractor and university leaders to work together to preserve programming space, keep the classrooms open during construction and preserve the sensitive historic façade while meeting the requirements of the University of California’s seismic policy.

The result was a renovation project delivered on time and 10% under budget. Elements of the process also helped set new standards for the UC system’s next generation of seismic retrofits.

“When you build these teams where everybody has ownership and everybody feels like they have a voice, I feel that they just run better,” Pittner says. “And you get better outcomes and people have more fun.”

The Challenge

Built in 1966, the York Hall four-building complex hosts most of the core undergraduate biology and chemistry classes and teaching laboratory spaces. Keeping the classes, labs and lecture halls open and operational during the seismic retrofit process was a top priority.

“We had to meet a specific seismic performance objective defined by the state of California and the University of California system, while not impacting the historic character of the building,” says LPA Director of Engineering Bryan Seamer. “And we had to keep it functional during construction.”

The classes and lab spaces were a maze of electrical, plumbing, exhaust and fire protection systems, complicated by almost 60 years of add-ons and renovations. Any attempt to move walls would send ripples through the project, forcing evaluations of how the changes would affect systems and the ability to keep the building open and functioning.

The distinctive fan-vaulted columns — supporting a rigid, heavy box structure — presented their own challenge. Any drastic seismic intervention that would alter the look of the historic building was off limits. Each column had its own issues and circumstances; each would need to be analyzed and addressed. The existing concrete fins cladding the complex presented a completely different set of issues (see sidebar).

“To not lose the historical integrity of the building was really, really important,” says LPA Design Director Matthew Porreca. “There was a lot of fear that we would have to do these bigger interventions that would drastically change the visual character of the project.”

The Process

A multidiscipline team was brought together from the start, including LPA’s mechanical, electrical and plumbing teams, as well as landscape architects and civil engineers to help with the connections to the historic plaza and surrounding buildings.

“In general, the integrative design process really is beneficial for highly complex projects, and complexity can come in many different forms,” Seamer says.

From predesign to schematic design, the team met weekly, including the contractor, PCL Construction, early in the design process. Discussions were structured around six basic priorities: seismic, historic, user operations, sustainability, budget and schedule. Every idea was filtered and analyzed through these six priorities. Concepts and different iterations of ideas would receive a red or green dot in each category from each discipline and participant — too many red dots could mean rejection, if the issue couldn’t be addressed.

Every concept had ramifications. A structural option might affect the plumbing and require shutting down the building; another choice might influence the façade. Decisions needed to be made quickly to keep the project on track. Architects were available to help determine the impact on the historic façade, a unique mix of precast concrete, masonry and minimalistic period details.

“Each location needed to be individually reviewed,” LPA Structural Managing Director John Wilson says. “A solution that worked well at one location might take half the campus offline at a different location, which was not acceptable.”

Ultimately, more than 15 different strategies were analyzed. UC San Diego representatives were fully engaged in the process, part of every meeting. They went back to their user groups to share updates and gather feedback for the team. At many points, Porreca was available to quickly illustrate new ideas.

“Matthew is the amazing sketchmeister,” Pittner says. “He can communicate a lot in a few really beautiful, simple sketches.”

PCL Construction and the structural peer review team were also integral members of the team and helped quickly analyze new ideas and provide feedback on cost and buildability.

“Everyone needed to be involved at every step,” Wilson says. “Otherwise, the whole project had potential for substantial setbacks.”

The Project

In a seismic retrofit, engineers often look for the most direct solution to remediate deficiencies and apply the same solution throughout. But that wasn’t going to work for York Hall.

An earlier assessment concluded 12 of the columns would need to be jacketed in steel. But wrap or paint would not hide the influence of the new steel on the visual profile of the colonnade, which made that option unacceptable from a historical perspective.

“The architectural team did a lot of work to understand what it would take to be able to implement the structural strategy without impacting the historic character,” Porreca says.

The team worked hard to design a solution that limited the column work to only four columns, which were replaced entirely to perfectly preserve the historic dimensions. This approach also reduced costs, materials and embodied carbon. The four critical columns were replaced with tightly tied rebar cages with new high-strength concrete cast into custom-built fiberglass molds, designed by a shipbuilder subcontractor to PCL, that perfectly replicated the hexagonal fan-vaulted shape of the column. One column sat directly above the 10-foot diameter utility tunnel that housed the main power supply for a large portion of the campus, requiring engineers to bridge over and around the tunnel with a combination of foundation beams and piers. LPA’s landscape architects and civil engineers helped restore the site to its original state.

During construction, PCL supported three-story sections of the west building on shoring stilts. “That only happened with careful coordination with everyone involved,” Pittner says.

The Results

To even the trained eye, there is little evidence of the structural improvement work done on York Hall. The distinctive minimalist mid-century clean lines and sculptural fan-vaulted columns have been restored to how they looked 50 years ago.

Due to careful and thoughtful project coordination from the entire team, the project came in under budget, which allowed UC San Diego to use contingency funds to address badly needed deferred maintenance and to make minor programming updates.

The project also contributed a new precedent for seismic evaluation to the UC system’s retrofit program. Technical standards developed for the project by LPA’s engineers, and confirmed by the system’s seismic advisory board, provided a new tool for meeting the technical requirements of the policy for upcoming future projects.

For Pittner, the project checked all the boxes for a successful project.

“In the end, it came off exactly the way we said it would,” Pittner says. “Absolutely everybody was happy, which doesn’t happen very often. And the team remembered it as a project that they really enjoyed.”

Sidebar: The Fin Solution

The seismic retrofit of York Hall was complicated by the 801 concrete fins that ring the façade of the distinctive mid-century complex. Weighing about 500 pounds each, the aging fins were deteriorating in La Jolla’s ocean air, and it was unclear what it would take — and how much it would cost — to solidify and repair them.

LPA’s structural engineers and architects came together with the builder to work the problem and design a universal strategy for strengthening the attachments and repairing the cracking concrete. Each fin was analyzed and evaluated. Different repair strategies, grouting and coatings were tested and discarded until a uniform strategy was developed.

Modeling and data visualization helped create “heat maps,” focusing on the four or five aspects of each fin that needed to be repaired. Revit software — a tool typically used for modeling buildings — was employed to create graphic representations of the fins, helping the teams understand and confront issues.

“At the end of the day it was all about mitigating risk and eliminating the unknowns for the contractor to get more accurate bidding,” LPA Structural Managing Director John Wilson says. When crews started working on the fins, they were armed with a step-by-step approach to addressing the repairs. Every detail was addressed, down to the specific grinding wheel to use. An app was created with a map of the specific repairs needed for each fin.

“When it went out to bid, we had basically a full recipe for each of the different interventions they might have to do for the various types of damage,” LPA Director of Structural Engineering Bryan Seamer says. Eventually more than 500 of the fins were repaired without any change orders, preserving the historical façade and helping to deliver the project under budget.