The permanent north span of the I-5 Skagit River bridge is ready to be put into place Saturday night — an operation that contractor Max J. Kuney says it can accomplish in only 12 hours.
Drivers will be detoured through the Riverside Drive bridge between Mount Vernon and Burlington overnight, from 7 p.m. to 7 a.m., the state Department of Transportation announced today. Traffic will exit I-5 at George Hopper Road to the north, or College Way south of the river, then drive through business districts.
A time-lapse video, available here, shows how over three days,
several weeks, a crane has lifted 160-foot long concrete girders and set them next to I-5, on platforms above the river. Road decks are now being built on the girders. On Saturday night, hydraulic jacks, Teflon pads, and steel rails will be used to slid the 900-ton span several yards upriver, right after the current temporary bridge is detached.
The original north span of the four-span crossing collapsed in May, after an overheight truck load smacked some crossbeams that were between 14 1/2 and 15 1/2 feet high, causing the steel truss to succumb.
The work is happening overnight to reduce the effects on freeway traffic, said DOT spokesman Bart Treece. The bridge carries an average 71,000 vehicles a day. Other overnight closures are likely this fall, when workers cut and replace several of the curved overhead crossbeams, raising them to 18 feet to reduce the risk of truck hits.