With the help of special skids and common soap, an Oregon contractor has replaced two bridges in two weekends as part of a $46-million design-build project for the Oregon Dept. of Transportation. Slayden Construction Group Inc., Stayton, broke ground on the project in June 2007 and wrapped it up in January, replacing a total of five 80-year-old bridges along Highway 38 between the towns of Elkton and Drain. Photo: Slayden Mammoet’s system allows new span in Oregon to slide sideways into place atop new bents. The project’s biggest challenge arose on two bridges known as Crossing 3 and Crossing 4.