 Water
Tower Place
Water Tower Place in Chicago was the tallest reinforced concrete
building in the world from 1975 to 1990, when it was surpassed in height by 311
South Wacker Drive, also in Chicago. Water Tower Place is 76 stories, 859 feet
tall and contains concrete with a strength of up to 9,000 psi. Named after
the Chicago Water Tower, the building was designed by Loebl, Schlossman, Dart
& Hackl. The commercial construction company who built Water Tower Place was
Inland-Robbins Co. A conventional design was used for the bottom 12 floors and
a tubular design for the top 64 stories, using lightweight and normal weight concrete,
as well as high strength concrete. Water Tower Place could not have been
built before the mid-1970s because concrete made before then would not have supported
the massive structure. In the 1950s, any concrete with a compressive strength
of 5,000 psi was considered high-strength. That definition changed in the 1960s,
when high-strength concrete was anywhere between 6,000 and 7,500 psi. It wasn't
until the early 1970s that concrete with a strength of 9,000 psi, the strength
of some of the concrete used on Water Tower Place, was developed. Advancements
in improving concrete's strength have continued to improve the material even beyond
the time Water Tower Place was created; modern concrete can reach strengths approaching
20,000 psi.  Only
some of the cement in Water Tower Place is a strength of 9,000 psi. Concrete contractors
used 11 different mixes, varying from 3,000 psi for the slabs to 9,000 psi for
the columns. The structural system of the building consists of reinforced concrete
on the outside with steel columns on the inside and steel slabs topped with composite
concrete. At 2/3 the height of the tallest steel building when it was built, Water
Tower Place serves as an example of how cement's abilities make it a strong rival
of steel.
Not only is the building composed of concrete, but concrete also
lies underneath the building site. Construction was delayed unexpectedly for several
weeks when the commercial construction company discovered a stream running under
the building site. They resolved the problem by creating a giant concrete dome
to plug the water so that construction could continue. Even though taller
buildings have been built since 1975, Water Tower Place, which remains fully operational
today, marked a major milestone for commercial construction companies in the advancement
of high-strength concrete and the new capabilities this innovation afforded.
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