A few key quotes from the report.

Quote Originally Posted by Teng Report from 1969
The fact that no catastrophic failure has occurred so far must be attributed to the load distributing effect of the corrugated steel deck and most likely also the absence of heavy eccentric loading. These conditions, however, cannot be relied upon indefinitely.
It is our understanding that there are annual bicycle and running events held around the Sylvan Island recreation area. Groups of runners can cause unusual vibrations in a structure, and that is a concern on these old shaky spans.
After inspecting this bridge and noting the extensive deterioration that has occurred, Missman concurs that closing this bridge to all access was an appropriate decision made by the City in April of 2013. Several members on both spans show significant corrosion, which has reduced the capacity of the bridge to safely carry pedestrian and bicycle traffic. One specific area of serious concern to note, are the bottom chord members near the abutments. These tie bars have over 50% section loss, and are a main load carrying members of the trusses. These are primary tension members, and are considered fracture critical. By definition, if any one of these members were to fail, there would be a catastrophic failure to the structure.
I am glad Harris brought up aesthetic considerations for the new bridge. I don't think a modern style truss bridge (like the one at Sunderbruch) would look appropriate given the setting. However, I realize they don't make bridges like they used to. Todays prefab bridges use welding as the preferred method of joining members vs gusset plates and rivets from 100 years ago which gives the structure a clean and streamlined appearance. It is not a deal breaker for me, but would be icing on the cake if the new bridge could incorporate some of the old world style (rivets, rust, the exaggerated truss profile and tunnel like "airy" form of long slender members).