Suppose you were given the job of raising the Norway Opera House five feet into the air. How would you do it?
To make the project more challenging, you cannot damage the building in the process. Also, the shops on the ground level must remain open so shoppers can visit them as the building rises.
Impossible? Not at all. In the mid 1800s, the city of Chicago needed to raise, not one, but dozens of buildings, many of which were taller and wider and heavier than our Opera House.
In its early days, the Windy City was not windy, it was muddy, sitting, as it did, on a boggy area next to Lake Michigan. As a village, this was inconvenient.
By the 1850s, Chicago had grown into a thriving city of more than 100,000. Because its elevation was about the same as Lake Michigan, it lacked natural drainage. What had been an inconvenience as a village, was a deadly problem as a city. Standing pools of muddy water and a lack of sanitation led to diseases such as typhoid fever, dysentery, and cholera. What was needed was a sewer system, but the city was so low, there was no way to install one.
The solution? Raise the entire city and install a sewer system at the old ground level.
By placing jackscrews under a building and having men turn them slowly at the same time, a building could be lifted and a new foundation built under it.
A jackscrew (also referred to as a jack screw or a screw jack) consists of a threaded rod in a threaded shaft. When the rod is turned, it slowly unscrews from the shaft, pushing upward as it goes. They don’t lift quickly, but they lift with a lot of power.
Early in 1858, the first place to get the treatment was a four story, 70-foot long, 750-ton brick building. Two hundred jackscrews were positioned under it and lifted it six feet two inches without causing any damage.
Many other buildings were raised that year, some as high as 14 feet.
The following year, efforts continued, including a fashionable, six-story hotel that was lifted six feet. It stayed open during the process, and not a single pane of glass was broken. One guest said that the ground-floor windows, which were at eye level when he checked in, were over his head when he checked out.
Work of this sort went on for a number of years. One of the greatest achievements was the lifting of an entire block.
Six thousand jackscrews were placed under a one-acre area of buildings, and over a four day period, the buildings, including the sidewalks, were lifted as one. Businesses on the block stayed open during the project.
All in all, the raising of Chicago was a feat that would have made even ancient Egyptians stop and take notice.
Sadly, many of the buildings that were laboriously raised in the 1850s and 60s were destroyed in the Great Chicago Fire of 1871.
Comments are not available on this story.
Send questions/comments to the editors.
