Portland State Magazine Fall 2018

25 THE MOOD was festive at the Hyatt Regency Hotel in Kansas City on the evening of July 17, 1981, with some 1,600 guests gathering in the hotel’s atrium for a dance. One of the defining characteristics of the year-old building’s atrium was a series of hanging steel and concrete walkways connecting floors between the hotel’s north and south wings. The weight of spectators on the walkways above the dance proved to be too much and caused them to collapse onto each other and onto the atrium floor, killing 114 people and injuring another 216. It was the deadliest structural failure in the United States until the World Trade Center collapse 20 years later. What happened and why? That’s the question posed to students in Franz Rad’s Forensic Engineering class every spring. It is the only class in the United States devoted entirely to the subject of investigating structural failures. The Hyatt Regency disaster is covered in the class, but there are many, many others covered as well. “A forensic engineer is basically a Sherlock Holmes—a sleuth,” says Rad, professor of civil and environmental engineering. “He’s somebody who looks around to find out what the hell went wrong, express it orally and in writing, and possibly come up with a way to fix it.” The Hyatt Regency tragedy is a classic example of structural failure brought on by a combination of cost-cutting and haste. As Rad tells it, the structural engineer for the project specified that the walkways be supported with steel rods hung from the ceiling. The same rods, each in one continuous line, would hold both the fourth floor walkway and the second floor walkway. The construction company had a different idea: Instead of the lower walkway hanging from the ceiling rods, they proposed it hang from separate rods attached to the upper walkway. The engineer signed off on the design change, which proved to be a fatal mistake; it completely changed the load-bearing characteristics of the structure. The history of building and bridge failure is littered with such examples: • The World Trade Center collapse in 2001. The buildings were designed to survive a plane collision, but not the extreme heat it produced. • The I-35 Mississippi River Bridge collapse in 2007, which killed 13 and injured 145 in Minneapolis. Gusset plates were used that couldn’t withstand the combined effects of age, vibration and overloading. • The Florida International University pedestrian bridge collapse, March 2018, killing six and injuring nine. The bridge cracked and failed in the final phase of construction. The cause is under investigation. • The Morandi Bridge collapse in Genoa, Italy, August 2018, killing 39. The cause is under investigation. RAD STARTED running seminars in failure prevention, attended by scores of practicing engineers, in 1975. He began his current forensic engineering class 14 years ago as a way to fill what he says is a fundamental gap in the way engineering is typically taught. “Engineering schools teach students how to design things. We don’t teach them what can go wrong, and why, and how to learn from it,” he says. Students who take the class—which include professional engineers—spend the term hearing and reading about 50 case studies, then writing reports on each of them. Rad presents some of the case studies, but he also brings in Portland-area engineers, many of whom travel throughout the world as forensic consultants. Rad joined the PSU faculty 47 years ago and is one of the longest-serving professors on campus. He was department chair for nearly a quarter century, as well as founder of the University’s i-STAR seismic testing lab. He says it takes about 20 years of experience to really be able to call oneself a forensic engineer. The class is designed to start that process, and can serve students and engineers even at the beginning stage of their careers. Graduate engineering student Robert Schneidmiller took Rad’s class last spring, then worked for the summer as an intern for a housing firm. “A large part of our work is foundation repair, which is typically the result of poor site preparation or foundation design,” he says. “While we do not perform any forensic investigations, I do try to quickly do a mental analysis for my own benefit and try to figure what happened with the original work.” The people who hire forensic engineers include lawyers involved in lawsuits, architects, builders, commercial property owners, other engineering firms—basically anyone who has a financial interest in finding the cause of a structural problem. Rad has served as a forensic investigator on dozens of cases over the past four decades. Most of the time, they are undramatic— solving the mystery of cracked kitchen tiles, or parking garage drips that stain the paint of expensive cars. They don’t involve injury or loss of life. But sometimes they do, as was the case in 1997, when three construction workers died during the building of a seven-story parking structure at Portland International Airport. The improperly connected steel sections they were working on gave way, killing them instantly. Rad served as a consultant for one of the victim’s law team. The case was settled out of court. Rad also was called to a seafood processing plant in Portland, whose owner was concerned about a wall that seemed to be shifting. When Rad arrived, he saw that a support for a huge concrete beam had cracked—the possible beginning of what could become a disastrous chain reaction. “I told the owner ‘I don’t know when this thing is going to fail, but it could fail as we speak.’ I said. ‘Everybody out!’” The 25 employees working in the plant were evacuated, and a contractor was ordered to quickly install about 100 6x6 timbers to support the concrete beams. The seafood processing operation was moved to a different location for the three months it took to permanently fix the problem. “The owner lost a lot of money, but I can’t take chances,” Rad says. A disaster averted is better than a disaster solved. In either case, it’s just another day in the life of an engineering sleuth.  A Florida International University pedestrian bridge collapsed five days after being installed in March 2018. (Pedro Portal/Miami Herald/TNS via Getty Images)