Fortifying the Castle on the Hill: Seismic Retrofit of UC Berkeley's Historic Bowles Hall

摘要

Bowles Hall is a reinforced concrete building of approximately 55,000 square feet on eight levels. The structure was designed in 1927 as the first residence hall in the University of California system. Designed by the architect George W. Kelham in the Collegiate Gothic style, the building is designated a landmark for the City of Berkeley and is listed in the National Register of Historic Places. A western trace of the Hayward earthquake fault passes underneath two corners of the building. In 2015, the renovation and restoration of the structure plus the construction of an addition was undertaken to revitalize the building's character and usefulness. The new work revises the dormitory room layout to include bathrooms within units, adds wheelchair accessibility, replaces or upgrades all building utilities, restores and protects historic features, corrects life safety deficiencies, restores dining, and adds conference capabilities. The renovation and retrofit are being carried out through a public-private partnership, and the dormitory will re-open as a coeducational "residential college." As described in a recent newspaper article, there will be "new keepers of the castle" (Whiting 2015). The remodel affords the opportunity to address remaining seismic deficiencies. Selective retrofit work had been done in 1977, and measures to accommodate earthquake fault-offset were constructed in 2009. Structural and seismic measures in the current construction include addressing discontinuous structural walls and constructing new building spaces, elevators, and stairways in a way that augments seismic resistance. Non-structural retrofit work includes developing secure attachment of historic tiles on the steeply pitched roofs and providing support for existing historic ceilings in the main dining and common rooms. Challenges of the project include a number of unique structural details, and development of an appropriate analysis strategy for a hillside structure in a location of extreme seismicity.