In 1991 the Landis family established the Landis Lectureship in honor of Donald Landis, a 1952 alumnus of the University of Pittsburgh. Since then twelve world-class structural engineers have come to the campus to present relevant lectures. This year, in honor of my retirement, I had the privilege of presenting the Landis Lecture.
Since I had been asked to focus on the insight that a long career generates, I titled the talk “Eight Decades of Gathering Wisdom”. I defined wisdom as the subconscious memory of thousands of relative experiences that have been properly evaluated and then discussed three traits that I believe are essential for a successful engineer – focus, judgment, and creativity.
The Florida International University pedestrian bridge collapse is an appropriate illustration of the consequence of losing focus. Proposed initially as a conventional bridge like the one Pitt has over Forbes Avenue in Oakland, a collection of non-engineers converted the design into an icon of public art, completely ignoring basic engineering principles.
Six days after high-fives celebrating the successful installation of the first component of this signature structure, it collapsed onto a busy highway, killing six persons, and demonstrating forever what happens when a design team loses focus.
The other highly publicized structural failure in 2018 is the TransBay Transit Center in San Francisco. Completed and put into service in August, it is an impressive six-level structure one small city block wide and one thousand four hundred feet long.
In mid-September a workman reported cracks in two girders spanning Fremont Street. Since a battery of hydraulic jacks have been in place blocking the busy street and holding up the girders.
The available information regarding the design is troubling to anyone knowledgeable about structural design. The girders in question are steel plate girders, each eight feet deep and spanning eighty-five feet.
The questionable design decisions include the girder flange thickness (four inches), a difficult butt weld at the most highly stressed area in the girder, failure to stress relieve the weld, addition of a massive concentrated load at mid-span, magnification of the high stress by cutting a large hole in the flange, and flame-cutting a weld access hole at the same point. This is a classic example of poor judgment, compounded six times.
Fortunately these bad examples were rare occurrences; the civil engineering profession had thousands of successes for every failure. I then used one recent success to illustrate creativity.
The Bayonne Bridge was the longest steel arch bridge in the world when it was opened in 1931. The recent advent of massive container ships has threatened to make the bridge obsolete, as it limits access to the Newark-Elizabeth container terminal, largest on the eastern seaboard.
The estimated cost of demolishing the bridge and replacing it with one with adequate clearance was more than could be justified. Fortunately some unidentified independent thinker eventually pointed out that there was nothing wrong with the bridge; it was the deck that was the problem. Why not just raise the deck? Excellent idea, one that could be implemented well less than a billion dollars. And a perfect example of creativity!
Pulling together this lecture was an humbling experience, particularly when I considered the stature of the previous lecturers. Nonetheless I enjoyed it and am honored that I was given this opportunity.