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Gerald C. Ratner Athletics Center
at the University of Chicago
Project
of The Year: Overall
The Gerald C. Athletics Center at the University of Chicago
represents a couple firsts.
It is the first athletics facility built on the Hyde Park
campus is more than 50 years.
And, the structure is reportedly the first asymmetrically
supported splayed-cable building in Chicago and possibly the
first in the country.
Cables Support Loads
The three-dimensional configuration of the structural system
has multiple levels of fore-stay cables that splay and support
loads in three directions.
The structural system for the gymnasium and natatorium features
tapered composite masts, each supporting and stabilized by
15 splaying cables, nine fore-stay cables and six back-stay
cables. They, in turn, support the flattened S-shaped roof
girders.
From the building interior, the system achieves architect
Cesar Pelli's goal of creating a delicate and uniform roof
structure with minimal structural depth.
Settlement of the masts could affect cable tension and unfavorably
redistribute loads throughout the structure - a concern with
any cable-stayed structure.
The issue was of particular significance with the Ratner center
given the soft clay layer near the surface at the project
site.
Ground improvements were necessary to transfer the masts'
gravity loads - almost 2 million lbs. per mast - to a suitable
soil stratum. The improvements were achieved through the use
of triple-fluid jet grouting, an erosion-replacement grouting
technique developed in Europe about 30 years ago and used
for the first time in Chicago.
Since the Chicago Department of Buildings reviewed the project
for a building permit shortly after the terrorist attacks
of Sept. 11, 2001, the city required the structural engineers
to review the structure's redundancy closely.
The city established its own criteria because redundancy for
this type of structure does not have precedent. This included
requiring investigating instantaneous cable failure.
The high-water table complicated the foundation design of
the pool and basement. Since water cut-offs were not an economically
viable option, the water table's hydrostatic pressure on the
basement slab is resisted by the weight of 30-in.-thick concrete
slabs.
Needed Facilities
The program - which included three dominant large-volume
spaces and natural light - drove the plan and architecture.
The primary elements included the following:
Competition natatorium with nine-lane pool and seating
for 350
Competition gymnasium with seating for 2,000 people,
one full-size competition basketball/volleyball court convertible
to two practice/recreation courts
12,500-sq.-ft. fitness center with multi-level cardiovascular
and weight training areas, dance studio and multi-purpose
room
Hall of Fame with juice bar and seating area with bay window
views of the natatorium
Building's Design Goals
The university sought a building to serve fitness, recreation
and competition activities for the university and neighborhood.
The building signals that the university is committed to
a healthy body, competition and fun. It is hoped the design
will help entice students who have traditionally regarded
the University of Chicago for lacking social life.
The Ratner site is located next to Amos Alonzo Staff Field,
which is used for baseball, football, soccer and tennis.
The university wanted the Ratner building to be a beacon
for the campus and to maximize the visibility of an athletic
facility.
The cable-supported structure opens the interior spaces
for free movement and natural light. Visible throughout
the 350-acre campus, the 120-ft.-tall masts soar above any
building except for Rockefeller Chapel.
This solution reduced the weight, quantity and cost of materials
used, allowed a 160-ft. span over the large volume spaces
using beams that are 33-in. deep - instead of the 8-ft.
that would be required by a typical structure - and also
created drama.
Transparency and volumetric drama throughout the building
generate excitement.
Visitors enter the rotunda where the Hall of Fame is located.
They immediately know they are in an athletic setting with
Jay Berwanger's Heisman Trophy, the first ever given, displayed.
Visible are the fields to the west, fitness activities above
and in front and the recreation gymnasium and natatorium
to the left and right. The glass walls that enclose the
main circulation system foster the experience of participation
in surrounding activities and provides orientation.
The jury said, "This project was challenging from the
get-go. A call came from the city two days after the Sept.
11, 2001, terrorist attacks in New York to review the project
and make sure it satisfied requirements. The result is a
very, very exciting place. It's quite the talk of the campus.
The facility is a beacon for 55th and Ellis avenues."
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