I was in the midst of trying to understand what is a viaduct when I traveled to Bethlehem, PA, with my family. One of our activities was to explore the bridges (see also Cage-free Bridges). As we walked the Hill-to-Hill Bridge, my initial reaction was “now here is a viaduct.” I hadn’t reached the point of developing a semi-clear definition for viaduct but looking at the flat roadbed supported by multiple arches over the floodplain, viaduct seemed the most appropriate word for the structure.
As we kept walking, it turned out that the viaduct was only a portion of the Hill-to-Hill Bridge. In fact, it would be more appropriately called the Hill-to-Hill-to-Hill-to-Hill Bridge. There are two approaches to the main span on the south end and three on the north end, including the viaduct and one approach permanently closed to through traffic. When the bridge was built in 1924, there were a total of seven approaches at various points along the main span. With so many components, this structure brings me back to the question of how many is one bridge?
Unlike when I asked this question of the 30th and 31st Street bridges in Pittsburgh, here the main bridge, the intersecting viaduct, and the numerous connections seem to be considered one bridge. They are together called the Hill-to-Hill Bridge while the structure in Pittsburgh has three distinct names (including River Avenue Ramp). Perhaps the deciding factor in whether it is one or more bridges is the original intent. The Hill-to-Hill Bridge was designed as a multifaceted structure whereas the 30th and 31st Street bridges were developed independently.
The best indication of the original intent seems to be the name. The Hill-to-Hill Bridge has a single name whereas the 30th and 31st Street bridges have separate names. The other examples I looked at in 2012 were the Veterans Bridge (Pittsburgh), the Fort Duquesne Bridge (Pittsburgh), and what I called the Jubilee Bridge (London).
The Veterans Bridge joins three approaches into one bridge, all under a single name. Therefore, it is one bridge, not three.
The pedestrian walkway of the Fort Duquesne Bridge was built decades after the vehicular portion but does not have a separate name. Therefore, it is one bridge, not two.
What I called the Jubilee Bridge (despite the photo I took at the time of the dedication plaque stating otherwise) is actually called the Golden Jubilee Bridges. While these bridges share the support structure of the underground’s Hungerford Bridge due to concerns about unexploded WWII bombs in the area, they have separate names. Therefore, it is three bridges, not one nor two.
Other posts in this series:
What is a Bridge? Pittsburgh Edition I (July 18, 2012)
What is a Bridge? Pittsburgh Edition II (July 27, 2012)
What is a Bridge? Chicago Edition I (April 18, 2013)
What is a Bridge? Chicago Edition II (February 1, 2020)
What is a Bridge? Bethlehem Edition II (July 15, 2020)