Nipigon River Bridge Update

Posted on September 22, 2016

In 2013, a contract was awarded to replace the two lane bridge with a new 4 lane cable-stayed bridge. Newly built westbound lanes were opened to two-way traffic on November 29, 2015. On January 10, 2016, 40 bolts connecting the girder to the shoe plate and the Northwest bearing broke, causing the end of the bridge to raise about 600mm.

Reasons The Bolts Broke:

  • Shoe plate was too flexible creating a "prying action" which increased the force on the two outer rows of bolts. This additional force resulted in the bolt heads/nuts bending, stretching, and eventually breaking.
  • Bearing did not allow for rotation without overloading the bolts. This lack of rotation increased the forces being placed on the bolts, causing the bolts to break.
  • 40 bolts were not properly tightened. Proper tightening keeps the forces in the bolts more consistent when the load on the bridge changes.

Permanent retrofit will now be installed which will allow for components to be inspected, maintained, and replaced with minimum interruption to traffic.

Emergency detour route assessment is underway. Field and geotechnical assessment is needed to move this development forward.

IMPORTANT DATES:

SPRING 2017 - TARGET COMPLETION RETROFIT

FALL 2017 - OPEN BRIDGE TO 4 LANES OF TRAFFIC

EMERGENCY ROUTE PLANNING AND ASSESSMENTS REQUIRE APPROXIMATELY 18 MONTHS TO COMPLETE

All reports now available on-line:

http://www.mto.gov.on.ca/english/highway-bridges/nipigon-bridge/