Sears Tower
The Sears Tower took roughly three years and $150 million to build. The
builders broke ground in
August 1970 and set the first section of steel for the bundled tubes in place in June
1971.
Starting with a hole 100 feet deep, builders laid the foundation of 200 circular caissons
set into the
bedrock. Prefabricated steel in 15-foot by 25-foot sections - called "Christmas
Trees" were put into
place, rising at a rate of about two floors a week. Four derrick cranes moved higher with
each floor to lift
the "Christmas Trees" into position.
The builders put enough concrete into the building to make an eight-lane highway five
miles long. Some
2 million cubic feet of concrete went into the foundation and all of the floor slabs.
Special elevators were
created to take the concrete mixed on site to heights above.
When it took too much time for workers on the upper floors to go down and eat their meals
at ground
level, special kitchens were created to feed them on two floors part way up. Practically
the only thing
that could stop construction was the wind, which blew so hard at the highest points that
the workers
could not even stand up, much less move across the beams.
By May 3, 1973, the last beam was put into place. It was signed by 12,000 construction
workers,
Sears employees, and Chicagoans who wanted their names on the world's tallest building.
Sears Tower Timeline
