The Florida Keys are connected to the mainland by U.S. 1, a narrow, 18-mile-long ribbon of two-lane highway sandwiched between the Atlantic Ocean and Everglades National Park. The Jewfish Creek Bridge rehabilitation—a four-year, $148 million Florida Department of Transportation project to reconstruct about seven miles of U.S. 1 where it enters Key Largo—required special attention to many environmental issues and constraints.
The National Institute of Standards and Technology awarded MISTRAS Software & Systems and its university partners $6.9 million under its new Technology Innovation Program for development and research of advanced technologies to enable monitoring and inspection of the structural health of bridges, roadways, and water systems. MISTRAS and its partners plan to develop a system for continuously monitoring the structural health of bridges using wireless sensors that obtain energy to power them from their structural vibration and wind.
An effective collaboration between architects, engineers, transportation officials, historic preservationists, and members of the community will provide the town of Norridgewock, Maine, a "modern" historic bridge. The new Norridgewock Bridge will incorporate key aspects of the old structure's design and will join the Depot Street Bridge in Oregon as the only modern concrete tied-arch bridges in the United States.
At the end of November 2008, a 397-ton wooden bridge was positioned over the A7 national trunk road near Akkerwinde in Sneek (the Netherlands), completing the first phase of a unique project. Prior to being transported with self-propelled modular transporters from the nearby assembly site to its destination, the whole bridge was lifted to a height of more than 16 feet using Enerpac's hydraulic computer-controlled Synchronous Lift System.
HC Bridge Maine, LLC recently announced that construction was completed on the High Road Bridge over Long Run Creek in Lockport Township, Ill., three months ahead of schedule. The structure is the first permanent highway installation of Hybrid-Composite Beams (HCBs), developed by the HC Bridge Company, LLC. HCBs comprise three main sub-components: a fiber-reinforced plastic shell, concrete compression reinforcement, and steel tension reinforcement.
Barry LePatner wrote in the Dec. 8, 2008, Bridges e-newsletter ("Report on I-35W collapse raises new concerns) of "a story out of Georgia in which reports identifying several bridges as hazardous" being "thrown away," ostensibly by an employee of the Georgia Department of Transportation. Would you or Mr. LePatner please provide me a copy of this "story," as I do not believe such an incident as described ever occurred? If, as I suspect, he was referring to a matter that occurred in January in which an internally initiated investigation determined two department bridge inspectors had falsified certain documents, allow me to provide a factual accounting.
It's been more than a year since the collapse of the I-35W Bridge in Minneapolis. And now, the National Transportation Safety Board has concluded from its investigation that the steel gusset plates originally designed in the mid-1960s to reinforce the bridge's joints were half an inch too thin; and that the probable causes for the collapse were additional modifications to the original design, which added substantial weight to the bridge, and the weight added by construction materials placed on the bridge by a contractor just prior to the collapse. That's it. And if you're thinking, "Surely, there was more to the collapse than that," you are right.
The question you need to ask isn't, "Is steel or concrete better for building bridges?" Every time out, we all need to ask, "What's best for this particular bridge?"
