| Building Type: |
Institutional |
| Original Structure Type: |
Concrete |
| Retrofit System Type: |
Steel |
| Year of Retrofit: |
2002 |
| Uploaded by: |
Private |
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Wurster Hall-School of Environmental Design
Wurster Hall, originally built in 1964, is a four story U shaped building with a 10 story tower on its north side. The original structural scheme was cast-in-place reinforced concrete floors, walls and columns with a pre-cast concrete exterior cladding and sunshades. An in-depth study in 1997 found that the ten-story tower lacked sufficient strength in the east-west direction and its discontinuous shear walls were likely to fail during a seismic event. The U-shaped plan of the building with its reentrant corners also created high lateral stresses in floor slabs. Additionally the interior and exterior gravity columns were in danger of collapse from the expected displacement and building drifts during an earthquake. In order to prevent collapse of the existing pre-cast façade columns, a series of steel columns were added on the interior of the façade to act as secondary gravity supports if the existing columns failed under earthquake stresses. The interior columns were strengthened by carbon fiber wrapping. To brace the north tower and provide additional occupiable space, two tube-like concrete structures were constructed on the east and west sides of the building with new drilled pier foundations underneath. Collector beams were built at each floor to tie the tube structure buttresses together with the existing tower structure to ensure that they would act compositely. The sunshades were also strengthened throughout the building to prevent failure. A unique feature of the retrofit was the use of fly ash (a by-product of coal burning that increases the concrete durability and is environmentally sustainable) in all concrete retrofit elements.
This University of California Berkeley building was retrofitted as a part of the SAFER Program (Seismic Action for Facilities Enhancement & Renewal) which systematically reviewed, prioritized, and constructed building retrofits for all UC Berkeley owned and operated buildings.
Retrofit Engineer: Forell/Elsesser Engineers
Retrofit Architect: Anshen and Allen
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