Design, improperly tightened bolts named as factors in Nipigon Bridge failure
A combination of design and installation deficiencies of several key components caused a bridge in northwestern Ontario to fail over the winter, severing a critical Trans-Canada Highway link, reports have found.
Two engineering reports, released Thursday, found that improperly tightened bolts on one portion of the Nipigon Bridge snapped, causing the steel decking to lift about 60 centimetres.
Other factors that contributed to the failure were the design of the shoe plate and its flexibility and a lack of rotation in the bearing.
The bridge failure last January, 42 days after it opened, caused up to 1,300 trucks — carrying an estimated $100 million worth of goods — to detour each day for several weeks.


