Lawrence Berkeley National Laboratory’s business is “providing scientific solutions to the world.” The institution’s impressive achievements include the discovery of sixteen new elements, the identification of good and bad cholesterol, and confirmation of the Big Bang theory. But when LBNL identified the need to seismically upgrade two of its aging structures; it relied on the problem-solving abilities of Nibbi Brothers and its subcontractors to handle the technically complex job.
LBNL’s “Seismic and Structural Safety Upgrades of Buildings, Phase I” project was a $17 million DOE (Department of Energy) line item project to correct the existing structural deficiencies in Buildings 50 and 74. The objective was to improve building performance in an earthquake by raising the U.C. Seismic Safety Rating of the buildings from “poor” to “good”, the highest available rating.
Retrofitting Building 50 required steel and concrete upgrades, including new foundation system, soil anchors, new concrete footings, and a new 16” cast-in-place wall to reinforce the existing concrete walls. Construction of Building 50, which houses the LBNL upper management, a clean room, the Lobby Museum and Auditorium, was accomplished while the building was occupied. Auditorium upgrades included seismic bracing and replacement of the ceiling and walls.
The structural upgrades on Building 74 involved replacing the steel bracing, strengthening the roof collector beam connections, installing new supports and grade beams, building new shear walls, strengthening weakened diaphragms, and removing the interior retaining wall surcharge. The building, which houses offices and labs, was unoccupied during construction.
In addition, exterior work included renovation of roofing and waterproofing as well as the addition of new windows and painting. The foundation system included new screw piles and new concrete footings. Construction was phased throughout the duration of the project as tenant relocation was needed within Building 50. Extensive asbestos & lead abatement was performed in both buildings. Specially trained workers and supervisors were fielded for demolition work in potentially radioactive areas.