|
Key Facts |
Bridge Name |
Type | Road | Location | City | Crossing |
| Smithfield Street Bridge | Truss | Smithfield Street | Allegheny County, PA | Pittsburgh | Monongahela River |
This is arguably Pittsburgh's most important historic bridge. It has five commemorative plaques on it, including one listing it as a National Historic Landmark! This is also my personal favorite of the Pittsburgh bridges. It is historic, beautiful, and unusual.
The Smithfield Street Bridge is a both a large and well-maintained example of a lenticular through truss bridge. Lenticular truss bridges are perhaps the most unusual of the truss bridge configurations. They are very rare, not just because they were demolished, but also because they were never a lot of them built to begin with. This is the only lenticular truss bridge that I know for sure I have seen. The Mill Creek Bridge looks like it could be a lenticular deck truss bridge, but I am not sure. Please email me if you know. Although I am fascinated by them, I am not a lenticular truss bridge expert, and so there are members, chords, bracing, and connections that I am unsure of what they would be technically described as. Lenticular truss bridges seem to have a hint of suspension bridge in them, with their extra hanging chord. As a pedestrian, you can feel this bridge flexes when heavy traffic crosses it, which has to do with the pinned connections, as well as perhaps the suspended quality of this bridge type.
This bridge has been restored, which is great because it means this bridge will be around for a long time to come. When you look at this bridge up close, you can find that there are numerous modifications. Some of these may be from the recent restoration, and others might be from other past repairs. Among the modifications I discovered were some extra steel welded to some of the eyebars, some rivets replaced with bolts, parts of bracing rods replaced, and some new turnbuckles. I even found that the top chords were filled with concrete! Despite these changes, the overall appearance of the bridge is great, and considering the age of this bridge and the amount of traffic it carries, it is still great.
