The I-85 North viaduct that was destroyed by fire on Thursday was last inspected by the state in August 2015. Here are some highlights of the report, which was provided by the Georgia Department of Transportation.
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The results refer not solely to the portion that collapsed but to the much longer bridge of which the collapsed section is a part.
1. The bridge was given a "sufficiency rating" of 78 on a scale of 1-100. This rating reflects the structural adequacy and safety of the bridge (accounting for 55 percent of the rating), whether its design remains adequate for the demands placed on it (also known as "functional obsolescence" and weighted at 30 percent of the rating) and how important the bridge is to the public (15 percent of the rating).
2. The bridge was first built in 1984 and then rebuilt in 1993.
3. The average daily traffic in in 2012 was 199,160. It has been estimated currently at nearly 250,000. The report says that, by 2032, the bridge will be handling nearly 299,000 vehicles per day.
4. The “deck” of the bridge, or the road surface, is concrete that measures 8.5 inches thick.
5. The condition of the deck, superstructure and substructure of the bridge are rated as 7, or “good” condition.
6. The report notes numerous instances of cracking in both the deck and the concrete retaining walls of the bridge. The cracks often are several feet long and typically measure 1/32 or 1/64 of an inch wide.
7. The bridge also shows a few instances of “spalling,” or deterioration of the concrete deck such that some of the concrete has crumbled away, leaving a ragged opening.
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