The Lower Bridge crossed the river between 10th Avenue on the Minneapolis side of the river to 2nd Avenue on the Saint Anthony side of the river. This bridge was built in 1874 as part of the agreement where the cities of Minneapolis and Saint Anthony agreed to merge. The Lower Bridge was a deck truss bridge built on a series of masonry piers, and crossed the river on a diagonal. This bridge deteriorated to the point where it was closed in 1934, and it was removed in 1943. One bridge pier still exists sitting in the water near the east edge of the river near the University steam plant.
The issue with the Lower Bridge is that it was designed for pedestrian and wagon traffic typical in the late 1800s. It could did not hold up to the pounding from automobiles, and it could not support heavy trucks. The structure was also too light to support street cars. The growing city needed another river crossing. In fact, as Central Avenue was becoming the center of commerce north of the river, and the new highway 65 was planned to follow Lyndale Avenue and Central Avenue, it turns out that the Lower Bridge was not in the best location.
To meet these needs, the City of Minneapolis started the process of building a new bridge that would connect from Third Avenue on the downtown side of the river to Central Avenue on the north side of the river. The bridge was designed in-house by Frederick Cappelen, a famous city bridge engineer. The bridge was started in 1916 and was finished in June of 1918. The curves in the bridge were dictated by the rock in the upper level of the Saint Anthony falls. The bridge needed good rock, and had to avoid locations where the rock was fractured. Once piers were built, large wooden structures called falsework was erected to support the arches while they were built. Once the arches were completed, the falsework was removed, and the spandrels and deck was installed.
As a result of its location on the edge of the falls, the bridge was known as the Saint Anthony Falls Bridge when it first opened. That name fell out of favor, and the bridge is now known simply as the Third Avenue Bridge. The Saint Anthony Falls name has since been applied to the new I-35W bridge. The Third Avenue Bridge is the longest S-curve shaped concrete arch bridge in the world. The bridge was marked as highway MN-65 until the mid-2000s.
By the 1970s, the Third Avenue Bridge had deteriorated badly. There was a debate whether it could be saved. The goal was to save the bridge since it is such a magnificent structure. However, if that was cost prohibitive, a new bridge would be needed. As it turned out, it was decided to replace everything from the arches up including the spandrels, deck, and guardrails. Once construction was underway, it was found that the bridge was in even worse condition that expected. At that point, it is likely that it would have been cheaper to abandon the project and tear the bridge down, but the city decided to continue with the project and refurbish the bridge. The rebuilt bridge opened in late 1980.
The photo above was taken late in the evening in the spring of 2005. The low angle light from the sun was able to get in behind the concrete supports and light up the inside of the bridge. The photo below is another image taken during the golden hour just before sunset. Here, we see the bridge bathed in yellowish sunlight while the buildings in the background appear to be in black and white due to being in the shade. This photo won the 2012 Othmar H. Ammann Award for best photo.