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The
George A. Roberts Engineering Hall is built into a steep hillside with the three exposed
sides featuring five stories of architectural exposed cast-in-place exterior walls. It
houses sophisticated optics equipment for materials science research, including five
electron microscopes. Built into a steep hillside and sitting only 50' from and active CSX
railroad line, soil vibrations pose a major structural problem. In addition, Roberts Hall
sits just below Hamerschlag Hall, the signature building and tower of Carnegie Mellon
University. Both the hill and Hamerschlag Hall are retained by permanent double-sleeved
soil anchors and shotcrete with movement monitoring points.
 
Based on the need to provide a stable
scientific environment, and to act as an architectural "base" for the historic
Hamerschlag Hall, a one-way concrete structure, with continuous concrete for the west
(downslope) facade and stair towers, was chosen. The facade provides a solid mass that
deadens vibration through the one-way slabs at 33'-0" x 22'-0" bay spans. The
contractor formed the walls and stair tower from six crane points on the rugged slope,
using HDO plywood and PERI KGE-240 climbing form system. All were placed predominantly
during the harsh winter of 1995-1996 that resulted in 75 inches of snow.
The design process examined alternative
systems to stabilize the hill, including the use of the building. With assistance from a
team of consultants, it was determined that the structure should be independent of the
hill stabilization to reduce earth-borne vibration into the structure. Roberts Hall was
built standing four feet free of the retaining wall. The one-way slabs actually move in
reverse wave of the train, reducing vibration for laboratory equipment. Concrete enabled a
wide means of control to achieve structural requirements of the program in the most cost
effective way. Roberts Hall is a demonstration of 1990's materials and concrete systems
used to establish a rich architectural dialogue in rhythm and form. |
