When I talked to Elaine Gregory McCluskey recently at her office at Fermilab in Batavia, Ill., and explained I was working on a story about engineering experiments at the Pruitt-Igoe housing project in the 1970s, she was bewildered. Why, why was I writing about Pruitt Igoe almost four decades after the place had been obliterated?
Well, here goes. In 1976, McCluskey was an undergraduate in the engineering school at Washington University. She, and two colleagues, Ronald Gardiner and James Vosper, also Washington U. engineering students, had been asked to assist in a plan by their professors to perform “full scale destructive testing of an 11-story reinforced concrete structure.”
That structure was a piece of the gigantic puzzle that was originally the Captain Wendell O. Pruitt Homes and the William L. Igoe Apartments, Pruitt-Igoe. It was located on 57 acres on the northwestern edge of downtown at the intersection of Jefferson and Cass.
The answer to Gregory’s very good question has a number of facets. First, Pruitt-Igoe has been in the news once again in St. Louis. Developer Paul McKee’s interest in this property has been keen. And the federal government is interested because it needs space on which to relocate the National Geospatial Intelligence Agency, which has outgrown its facilities in South St. Louis, across Second Street from Lyon Park.
Those are the major players, but other things have transpired. An international competition was initiated three years ago by preservationist Michael Allen calling for comprehensive designs for the site, and “The Pruitt-Igoe Myth,” a movie released in 2012, offered a frank discussion of reasons for the decline and fall of the housing project. Last year, New York-based artist Mary Miss and others toured the site with an eye toward urban revivification as a constituent of art.
And despite the passage of almost four decades, Pruitt-Igoe continues to be regarded by some as the final nail in modernism’s Corbusian coffin. Postmodernist pundit Christopher Jencks, indeed, called the end of the project “the day Modern architecture died.”
In any event, to provide a broad, general answer to McCluskey’s query: Pruitt-Igoe has never gone away, and that is the reason I’m writing about it again. But there is another reason for writing about the engineering students’ experiments: The results may have brought a few rays of positive light to shine upon a project steeped in doom. In other words, it’s a way to sew up a small silk purse made from a colossal sow’s ear.
Learning about structures
When the three students first stepped onto housing project site in 1976, scattered evidence remained of what was intended to have been a model residential complex. It opened for residents in 1954 and almost in no time it began its slide, eventually to become a most notorious housing project experiment.
Gardiner, McCluskey and Vosper led the charge not to test the viability of Pruitt-Igoe as a dwelling place for a massive poverty-stricken population but to apply physical testing to discover how strong buildings built to accommodate all sorts of populations should be constructed. The destruction-focused testing concentrated on one of the last vandalized and vacant towers of the complex. These experiments led, as Gardiner wrote in the report to the National Science Foundation, which funded the experiment, “to an opportunity to learn more about real-world properties on this kind of structure.”
In addition to the NSF. both the McDonnell Douglas Corp. and the Boeing Co. – rivals in the aerospace business -- provided equipment, personnel and, one must assume, encouragement. Gardiner wrote that the testing was based on the vision of Theodore V. Galambos, who at that time chair of the civil engineering department at Washington University, and David S. Hatcher, a professor in the department.
Pruitt-Igoe history
The Pruitt-Igoe housing project was finished after many turns of governmental screws and the applications of value engineering to beat the band. There were 33 formidably constructed buildings of 11 stories each.
At first, in the mid-‘50s, Pruitt-Igoe was considered a new Canaan in the subsidized housing world – clean, airy, efficient, designed by a firm with impeccable credentials (Hellmuth, Yamasaki and Leinweber, St. Louis). Minoru Yamasaki was the lead architect. He would go on to design the brilliant terminal building at Lambert Field as well as the tragic World Trade Center in New York.
Pruitt-Igoe was distinguished initially by being constructed of first-class materials and by plans to set it in what was shown in renderings as parkland. Its promise was better housing and a better environment than most of its tenants ever experienced. The project was trumpeted as a triumph of design and community planning. It was pretty to think that, but ultimately wildly, heartbreakingly wrong.
One way or another, it all fell down, in fact and in Humpty-Dumptian metaphor. Today the site is a tangled and abandoned dystopic Eden, impenetrable in places, as fascinating as it is troubling, retrospectively sickening.
Destructive testing
But in 1976, the remains presented a great opportunity for Gardiner, McCluskey and Vosper -- and for science. All three engineers have had successful careers – Gardiner and Vosper in aerospace at McDonnell Douglas and Boeing, and McCluskey, now at the Fermi National Accelerator. But then they were summoned to participate in a series of experiments at Pruitt-Igoe. In a report to the National Science Foundation, Gardiner described a building that remained “a rare opportunity to perform full scale destructive testing of an eleven-story reinforced concrete structure.”
Mark Holly, also a Boeing engineer, read something I wrote about Pruitt-Igoe and introduced me to this extraordinary experiment.
“Pruitt-Igoe,” Holly said, “represented an opportunity to collect real data from a real building.” Originally I thought surely these experiments had something to do with the seismic hazards facing St. Louis because of its proximity to the Reelfoot Rift, in the confines of which the New Madrid Seismic Zone lies. Not so, Gardiner explained. In wide ranging and generous emails, he said, “The interest in this project was not so much driven by the seismic instability of our area, but rather by the unusual opportunity to study a representative modern reinforced-concrete structure, both non-destructively and destructively.
“To make the project even more valuable,” he continued, “we had available design drawing for the structure. Not too many owners are going to volunteer their costly structures for this type of testing.”
Dual goals
There were two objectives, Gardiner explained. One was to investigate the on-site structural dimensions and material properties of the structure. That part of the study, presented in an abstract published by the Sever Institute of Technology at Washington U., and written by Gardiner and Professor Hatcher, concluded “that variations of dimensions and properties of the structure investigated are generally similar to those of other buildings, and that the average strength of the members exceed the design strength.”
The second part, Gardiner said, was to study how much the building moved under small amplitude testing and to observe structural damage and the degradation of the dynamic characteristics due to large amplitude shaking tests.
David Marshall, an engineer also retired from the Boeing Co. after 35 years, came from Boeing to work on this project and became one of the leaders.
“Dr. Galambos said that this was a good opportunity to test the strength of relatively new building techniques,” Marshall said.
The Pruitt-Igoe buildings were large and almost entirely standardized. Gardiner said, “Dr. Galambos and Dr. Hatcher proposed to study one of the 45 by 50 foot towers that anchored each end of the structures. To facilitate the effort, [one of the tower structures] was separated from the center of the building using jack-hammers. The center portion of the building and the tower at the other end were then dropped by explosives, broken apart and carted away.”
The builders of Pruitt-Igoe created steel reinforced concrete columns and beam. They then put cinderblocks between columns around the periphery of the building and a façade of brick was installed on the outside.
Marshall said, “The idea was we would follow a procedure common in the aircraft industry, and that was to make a modal survey of the building. A couple of frequencies were selected to establish the first and second vibration modes in the building so that the effects of shaking could be measured.”
Marshall said that the contractor directing the main demolition effort on the other buildings lent the services of a crane to the research project. A description of what was done is below, and many of them were Herculean. All the materials for the shaking mechanism – steel, iron, ball bearings, hydraulic pump and water for heat exchange – had to either be carried up by hand or hoisted up to the roof then dropped through a hole cut in it. The actual mechanism was on the 11th floor.
According to Marshall, "A steel plate was put down on the floor and a batch of ball bearings were put on the plate. An 8 by 8 by 1 ½-foot steel box was put down on the ball bearings and then filled with 60,000 pounds of rented lead. ... We had to remove the lead and reinstall it when we changed from the east-west direction to the north-south direction. ... A large mass such as that has a lot of inertia so a lot of force had to be generated to move the mass and then a lot of force in the opposite direction to stop the moving mass and pull it back."
Appliances and junk left behind had to be heaved out of the building by hand before shaking could begin.
The building sways
“A hydraulic cylinder four feet long was put in place -- one end of it was attached to the box and the other end was braced against a column” Marshall said. When activated, this assembly shook the building, alternately in north-south and east-west directions.
Elaine Gregory McCluskey, James R. Vosper, Ronald A. Gardiner, David Marshall and Mark Holly were extraordinarily generous with their memories and their time. Individually and together they provided much of the information on the Pruitt-Igoe experiment and qualify as co-authors of this story.
“Because of the inertia of the contents of the box, when you tried to move it, it would push back, but as you accelerated and pulled back, and as you changed how fast you did that, you hit the resonance of the building, which then would start to sway.
“The farthest we got was 39 inches,” Marshall said. “I walked around in the building as the shaking was going on: It was hard to walk,” he said. All this was being measured, including the seismic energy transmitted into the ground. No seismic effects in the ground were detected.
Jim Vosper recalled that, at this point, cracks came in the corners, and one could see the movement of the building. “Spectators could see falling concrete. Some brick veneer separated from the concrete. Soon, the cracks in the building occurred with greater frequency and concrete would break away.” A stairway on one side zigzagged up floor to floor, and as the building was shaken it stiffened that side of the building. In the east-west direction the motion was straight in line with the force applied, but the north-south direction would cause the building to twist.
“Finally one column cracked completely through and the reinforcing steel bent – still attached to the building.”
Opportunity in failure
For years, observers have ticked off problems that had nothing to do with the external appearance of the buildings. The elevators stopped at every other floor, so residents, many of them elderly, had to walk up or down stairs to get to their dwellings. There was no provision made for children to play safely outside. The apartments were all the same, so there was no individuality, and the rough concrete walls and cheap wallboard were not attractive. Vandalism was home grown. The project became a center of dope use and dealing. Although all of that contributed to the failure of Pruitt-Igoe, so did a shocking lack of maintenance and supervision.
Ironically, “[t]he social failure of the housing complex led directly to the availability of the building and to this opportunity to learn more about real-world properties on this kind of structure,” Gardiner said.
But there was more, as Jim Vosper noted.
“This was research that could go to the improvement of places for people.”
