Doing More with Less: A Targeted Seismic Approach

A series of case studies illustrating cost-effective, sustainable design solutions that save materials, energy and water.

The Client:
UC San Diego’s four-story York Hall is a distinctive part of a historic section of the campus. A fluted colonnade supports a bar-shaped structure that appears to levitate above a student walkway. The exterior is lined with concrete fins which provide sun shading and define the building’s aesthetic. The structure needed to be retrofitted to meet University of California seismic standards, while preserving its graceful architecture and avoiding disruption of academic life.

Seismic Approach 1 Seismic Approach 2

The Solution:
York was the first UCSD project in a systemwide UC program to assess older buildings, identify seismic risk and prioritize retrofits. Working closely with the UC Seismic Review Board, LPA structural engineers started the project with an effort to analyze and validate the UC system’s process for seismic upgrades, which would inform the entire system’s retrofit program.

After careful study, the LPA design team presented four retrofit options for York Hall, visualized in a decision matrix that compared each solution’s performance relative to six interdependent priorities. UCSD selected a targeted approach, which started with an in-depth investigation of conditions and favored surgical interventions rather than approaches that would cost more, reduce program space and inconvenience stakeholders.

Seismic Approach 3
Footings and shoring supported the building while crews made the surgical improvements.

The LPA team identified two critical elements: the fluted colonnade and the 805 vertical concrete fins. The team replaced four critical columns using fiberglass molds that perfectly replicated the hexagonal fluted tulip shape, while including tightly tied rebar cages within to allow the building to safely resist large earthquakes. An app was created with a user-friendly map of all 805 fins, annotated with the specific deficiency and corresponding repair needed for each fin, allowing contractors in the field to target damaged steel connections.

Overall, the simplified retrofit process resulted in cost savings of about $3 million, which was reallocated to other campus projects. The targeted retrofit approach was also developed as a model for future UCSD seismic retrofits.

“The key innovation was how we helped the client mitigate risk at every step in the process,” said LPA Director of Structural Engineering Bryan Seamer. “By thoroughly understanding UCSD’s multi-faceted needs and leading a process that provided clarity and transparency to the prioritization of those needs, we were able to add confidence to the bidding process, and ultimately save money.”