The new Lowry Avenue Bridge will be a basket handle arch bridge. As an arch bridge, it will have two large arches that rise nearly 200 feet above the river. A basket handle arch has the two arches tilted towards each other such that they meet high over the center of the bridge. The 450 foot long main span deck will be suspended under the arch using cables. One interesting feature of the new bridge is that the arches rise up from the river level rather than starting at the level of the deck as in traditional arch designs. The traffic lanes will go through the two arches, but the sidewalks will curve around the outside of the arches.
The basket handle arch design is relatively rare in the US. There are several signature basket handle arch bridges in Asia, notably in Japan. There are no other such bridges in Minnesota or anywhere along the Mississippi River. Interestingly, there is a Lowry Bridge in the United Kingdom, and it also happens to be a basket handle arch bridge.
The remainder of the bridge spans will be concrete of either the prestressed or post-tensioned design. There will be a smaller pier on the east side of the river to allow for a short span to accommodate a future regional trail to cross under the bridge. The west end of the bridge will also have a pier, and then the west abutment will be next to that pier. This is to allow the abutment to be removed at some point in the future to allow for the bridge to be extended to Washington Avenue. This is to provide for the possibility of the land on the west side of the river to be redeveloped and not be divided by the current earthen embankment. The goal is to someday removed that embankment and possibly create a park.
The first bridge at this location was built in 1887. A new bridge was built in 1905 featuring 5 steel truss spans. That bridge carried traffic for 51 years until it was deemed to be unsound. The truss spans were replaced in 1958 with 5 new steel trusses, this time, built much heavier. The new trusses were also wider to allow 4 lanes of traffic. In addition, the 1905 era bridge piers were widened, reinforced, and built 20 feet taller to allow river navigation under the bridge in anticipation of barge traffic on this section of the river with the completion of the locks at Saint Anthony Falls in the 1960s. The 1958 structure was found to have a problem with a pier shifting, resulting in the bridge being closed in 2008 and being demolished in 2009.
Click here for complete coverage of the 1958 era Lowry Avenue Bridge.
As of June 2009, the 1958 era bridge has been dismantled, but its piers remain in the river channel. A test piling is being sunk into the river to verify the design of the piers. Construction on the bridge is planned to begin in late summer or early fall of 2009, which completion in late summer or early fall of 2011.
Update—the new Lowry Bridge opened on the afternoon of Saturday, October 27, 2012, following a public open house and a short parade. Despite being a year behind schedule and millions over budget, the massive structure is set to become the centerpiece of a riverfront redevelopment now that the Port of Minneapolis is set to close. I have many dozen photos to put up someday, so please check back for updates.