I Note That the Sufficiency Rating Is 44.12 and the Bridge Is Considered Structural Deficient

Craig, Thank you for the drawings, inspection reports and underwater investigations sent with your two emails of October 31, 2016.

I note that the Sufficiency Rating is 44.12 and the bridge is considered structural deficient. The superstructure has a condition rating of 4, meaning it is in poor condition with advanced section loss, deterioration, and spalling. There are signs of flaws in the original construction, such as poor concrete consolidation resulting in extensive rock pockets and spalling with exposed rebars.

Although the substructure has a condition rating of 5, it also is experiencing signs of distress and scour. Likewise, there seems to have been a rather low grade of concrete specified for certain portions of the substructure. I wish to quote the specification: "... the concrete in the abutments, piers and footings consisted of one part cement, three parts sand and six parts broken stone, ranging in size from 1/4-in. to 2 in. pieces. In the massive portions of these parts of the structure, one-man stone were embedded in this concrete in a quantity not exceeding 30 per cent of the entire volume. The large stone were set at least 6 in. from the surface of the concrete, with a minimum of 4 in. of space between the pieces."

A one-man stone seems to have a variety of definitions depending on the individual, However, generally it means the weight of a stone that can be carried by one man. Of course, depending on his strength this could be stone the size of a bowling ball and beyond that of a basketball. I believe it is obvious that with the concrete mix consisting of six parts of broken stone up to two inches in size, along with 30% of the volume containing stones in size as described above, the concrete is probably of very low strength.

Scour has been taking place at several of the footings and concrete sacks have been installed in those locations to minimize the action. Unfortunately the sacks have been deteriorating and the scour has started again undermining the footing in those areas.

With the structure being over 100 years in service, and in view of the state of deterioration and questionable strength of concrete, I regretfully believe it's life expectancy is nearing the end.

A Happy Thanksgiving to all, Bob