The new home of the Berkeley Art Museum and Pacific Film Archive officially “bottomed out” in November, making way for the new home of BAM/PFA to rise along Oxford between Center and Addison Streets in downtown Berkeley, California.
Originally slated to be demolished, a retooled approach to the museum required portions of the landmark New Deal-era UC Press Building – where the signatory copies of the United Nations Charter were printed in 1945 – to remain in place.
Degenkolb Engineers was tasked with developing the structural engineering approach to maintain the building and perimeter walls in place during construction and excavation. To preserve parts of the historic building, including the exterior walls, the project had strict requirements for minimal movement, seismic safety, and differential soil surcharge. Degenkolb and Plant Construction, along with Condon Johnson Associates, developed a streamlined approach to temporarily ‘float’ the Admin block.
The system utilized deep foundations on both sides of the building with steel ‘needle’ girders running across the full width of the building.
To keep the building flat but deflect (sag) the needle girders downward, we used an iterative technique that used jacking, cutting, shimming, and setting back down in a multi-part sequence. This prevented the building from sagging in the same shape as the needle girders, which were expected to deflect up to 4 inches in the middle of the building.
Lateral seismic and soil loads were resisted with a second line of deep foundations and backstay elements on the east side, with capture rods running across the floor plates. This prevented the need for buttresses on the west side of the building, which would have conflicted with the new construction.
Three-dimensional Building Information Modeling (BIM) was used to develop the system, to collaborate with the project team, and most importantly – to weave the temporary elements through historically sensitive areas.
Though our work will not remain in the final building, it was a critical step in the preservation and transformation of this downtown Berkeley landmark. As development continues to honor the past but push forward into the future, we are increasingly tasked with complex Construction Means and Methods projects. These are five-dimensional challenges of space, time and budget to safely and efficiently transform existing sites into new landmarks.
We thank the University of California, Berkeley, and project partners Plant Construction and Condon Johnson Associates. Special thanks to structural engineer of record Forell/Elsesser Engineers.
Stay tuned for more floating buildings and bottoming out parties, including the Presidio Knolls School in San Francisco and the Old Chemistry Building at Stanford University.
*pictures by Alejandro Velarde.