Active Project Report

The Arden Bridge in central Stevens County was built in 1917 and is a 67 foot long, 24 foot wide, two span concrete “T” beam bridge. Tthe bridge was originally constructed as part of the state highway system. The road is now owned by the county. The county conducted its yearly scour critical inspection after the unusually heavy runoff this spring and discovered a severe scour issue that required closing the structure and calling in a structural engineer to make an assessment of the problem. As a result of the inspection, the sufficiency rating was dropped from 49.31 to 30.06 SD. The inspection also recommended the bridge be closed to traffic and the shoreline access restricted. The issue of immediate concern is the center pier of the bridge which has a spread footing that has been completely undermined, with debris trapped under the footing. On July 26, 2011 the county declared a bridge closure emergency to protect the public. The bridge had been closed to traffic on July 6, 2011 in anticipation of the emergency declaration. The county and structural engineer consultant determined that the bridge needed a full replacement of the structure with a new 80 ft span bridge. The new bridge will meet all current standards and be supported by bearing piles, pile caps and pre-stressed concrete beams to carry the projected 600 daily traffic volume. Some channel work will be required and stream bank protection measures will be installed to mitigate the scour situation. CRAB awarded $650,000 in emergency RATA funding on July 28, 2011