Over time, the joints can crack, allowing water and salt to infiltrate in winter. The salt corrodes the steel reinforcing cables within the concrete. As the strands break, the bridge weakens. We can therefore assess the hidden damage and evaluate the remaining capacity and life of the structure by inspecting the location and amount of rust on the surface. As traffic flow increases and heavier truckloads are permitted, bridges can become obsolete, Hawkins said.
Bridges often have to be updated, and that means replacing the deck beams with stronger ones.
We consider a successful bridge as one with a 50-year service life. Down the road, the ultimate solution lies in building better bridges. For example, the state now incorporates corrosion inhibitors in the concrete to significantly reduce the likelihood of corrosion and increase the service life. Bridges in Illinois are inspected every two years, Hawkins said. Deck beams are fairly easy to replace once they have been identified as bad, so it's mainly a matter of being vigilant.