Civil engineering

Summer 2024’s record heat is creating problems for transportation infrastructure, from roads to rails. New York’s Third Avenue Bridge, which swings open for ship traffic on the Harlem River, was stuck for hours after its metal expanded in the heat and it couldn’t close. Roads have buckled on hot days in several states, including Washington and Wisconsin. Amtrak warned passengers to prepare for heat-related problems hours before a daylong outage between New York and New Jersey; the risks to power lines and rails during high temperatures are a growing source of delays for the train system. It doesn’t help that the worsening heat is hitting a U.S. infrastructure system that’s already in trouble. The American Society of Civil Engineers gave U.S. infrastructure an overall grade of C- in its latest national Infrastructure Report Card, released in 2021. While there has been some improvement – about 7.5% of U.S. bridges were in poor condition, compar...

“Can you name the truck with four-wheel drive, smells like a steak, and seats 35?” Back in 1998, “The Simpsons” joked about the Canyonero, an SUV so big that they were obviously kidding. At that time, it was preposterous to think anyone would drive something that was “12 yards long, two lanes wide, 65 tons of American Pride.” In 2024, that joke isn’t far from reality. And our reality is one where more pedestrians and bicyclists are getting killed on U.S. streets than at any time in the past 45 years – over 1,000 bicyclists and 7,500 pedestrians in 2022 alone. Vehicle size is a big part of this problem. A recent paper by urban economist Justin Tyndall found that increasing the front-end height of a vehicle by roughly 4 inches (10 centimeters) increases the chance of a pedestrian fatality by 22%. The risk increases by 31% for female pedestrians or those over 65 years, and by 81% for children. It’s hard to argue with physics...

Heavy rainfall generated widespread flooding. in the Upper Midwest in late June 2024, putting at least one aging dam at risk. In southern Minnesota, the Blue Earth River cut a path around the Rapidan Dam in Rapidan Township, about 15 miles south of Mankato, on June 24, putting the structure at imminent risk of failing. Officials warned local residents that if the dam burst, the river could rise by 2 feet, but said that evacuations were not needed. This event comes a year after flooding in Vermont collapsed at least one dam and threatened others. Hiba Baroud, associate professor and associate chair in the department of civil and environmental engineering at Vanderbilt University, explains how flooding stresses dams in a changing climate. How serious is the risk when water flows over or around a dam? These conditions can result in erosion, which subsequently could lead to a dam breach or failure and a sudden, uncontrolled release of impounded water. The risk reflects the combin...