Books You Should Read: Why Buildings Fall Down [Hackaday]

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People with long commutes usually come up with tricks to stay focused and alert and avoid the dangerous tendency to zone out during the drive. One trick I used to use was keeping mental track of the various construction projects I’d pass by on my way to work, noticing which piers on a new highway overpass were nearing completion, or watching steelworkers put together the complex rebar endoskeletons of a new stretch of roadway.

One project I loved to watch back in the 80s was a new high-rise going in right next to the highway, which fascinated me because of the construction method. Rather than putting together a steel frame, laying out decking, and covering each floor with concrete, the workers seemed to be fabricating each floor at ground level and then jacking them up on the vertical steel columns. I was fascinated by this because every time I passed by the floors were in a different position, spreading out vertically as the building grew.

And then one day, it just wasn’t there anymore. Where there had been columns stretching nine stories into the city sky with concrete slabs lined up ready to be jacked up into their final positions, there was just an enormous hole in the ground with a ghastly gray cloud of concrete dust rising from it. It was April 23, 1987, and what was once going to be a luxury apartment building called L’Ambience Plaza in Bridgeport, Connecticut lay pancaked into the ground, entombing the bodies of 28 construction workers.

House of Cards

The collapse of L’Ambience Plaza is just one of the many case studies contained in “Why Buildings Fall Down,” a book that Matthys Levy and Mario Salvadori wrote in 1992. I stumbled upon the book not that long after it came out, and was instantly drawn to it because of my connection to the L’Ambience Plaza collapse; the job I was commuting to that day was actually as an emergency medical technician for an ambulance company in a neighboring city, so many of my friends were down in that hole trying to rescue construction workers as I was passing by, and I actually went to the scene later that day to volunteer my services. By the time I read this book I was already out of the EMS business and far more interested in the engineering aspects of what went wrong that day, and this book provided a detailed case study on L’Ambience Plaza that satisfied my curiosity about what happened that day, as well as more than a dozen other structural failures, most of which also resulted in at least some loss of life.

Each case study in the book is accompanied by simple but excellent diagrams by Kevin Woest that make it easy to understand the root cause of each failure. For L’Ambience Plaza, the threaded jack rods were found to pass through slots in the steel lifting frames rather than holes, which would have prevented them from slipping out and starting the progressive collapse that took the building down. The diagrams make this quite clear, and it’s easy to see why the mechanism was built the way it was; feeding a 1-1/4″ threaded rod through a hole is much harder to accomplish on a job site than slipping the lifting nut into a slot. But it’s also easy to see how that nut could slip out of the slot and cause a lot of trouble in the process.