Workers on the Humpback Bridge replacement, located on the George Washington Memorial Parkway just north of Interstate 395 and immediately south of the Columbia Island Marina, are closing in on the final round of safety improvements. In the process, they are preserving the grace of the bridge's original stone arch structure, says Chris Scott, a general manager for Cianbro, Pittsfield, Maine, the construction firm working on the job. Courtesy of Cianbro OLD BRIDGE, NEW IMPROVEMENTS Workers are slated to complete the bridge improvements by the end of this month. Workers on the Humpback Bridge replacement, located on the George Washington
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.