It is said that necessity is the mother of all invention. If that is the case, then the need for striking, elegant cable-stayed bridges that can span greater lengths and be more easily maintained over the course of longer lives has yielded a significant new invention that may well benefit bridge designers the world over.Driven by a desire to push the design of single-plane cable-stayed bridges beyond their current limits—both in span length and in aesthetic appeal—while still delivering an economic solution that is easy to construct and maintain, FIGG, an engineering firm based in Tallahassee, Florida, has created a novel system for routing stay cables from one end of a bridge deck, through the bridge’s pylon, and then down to the other end of the deck in a way that precludes the possibility of cable-to-cable interactions.The innovation has been employed on two new bridges—the Veterans’ Glass City Skyway Bridge, which carries Interstate 280 across the Maumee River in Toledo, Ohio (see “Ohio DOT Endorses Design for Maumee River Crossing,” Civil Engineering, September 2000, page 12), and the Penobscot Narrows Bridge and Observatory, which carries U.S. Route 1 over the Penobscot River in southeastern (“down east”) Maine near the coastline (see “Observatory to Cap Maine Crossing,” Civil Engineering, April 2025, pages 15–17).The cradle offers benefits both during construction and over the life of the bridges. Most important of all, it permits the use of the largest number of strands within a single stay cable in the world: 156, an increase of more than 70 percent over the second-highest number known to have been used in the United States. It also makes it possible to increase the dista...
