Category Archives: Bridges

What is a Bridge? Bethlehem Edition I

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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.

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Cage-Free Bridges

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The summer I spent walking Pittsburgh bridges, I complained about the cages on the Millvale Avenue Bridge, the Highland Park Bridge, and the Graham Street pedestrian bridge. The narrow sidewalk and chain link fences on the first two examples and the chain link cage on the third example made me feel yucky and claustrophobic. Thanks to one of my blog followers, I recently learned that people tend to throw things onto moving objects, which is why bridges like the Millvale bridge have higher fencing along portions over roads and railroads. I still wished there was a cage-free option to meet the same goals of the bridge builders.

In Bethlehem, PA, I found just such an option on the Fahy Bridge. It is a fairly plain concrete bridge saved from the ugliness and gloom of many concrete bridges by using a functional, yet decorative, railing instead of the more common functional, yet ugly, chain link fence. This railing was installed during the 2016-18 renovation of the Fahy Bridge. Recent bridge renovations and replacements in Pittsburgh also feature more decorative railings. While the first of these new bridges in Pittsburgh tried to dress-up a chain link fence cage, the later ones are successful cage-free bridges even when they incorporate chain link fencing.* These examples give me hope that the days of caged bridges may be a thing of the past.

*Note: I have a to-do item to go back and photograph these new bridges for future posts, but no set timeline for the completion of this task.

What is a Bridge? Chicago Edition II

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While poking around the map collection at Chicago’s Public Library, I discovered that the structures carrying roads over the railroad tracks in Grant Park are considered viaducts. The word viaduct brings to my mind a Roman structure soaring over a valley floor and conveying a flat road on top of towering stone arches. The Chicago “viaducts” do not fit that image. To me, they look like bridges with no striking difference between them and Chicago’s river bridges other than color and style of ornamentation. Both groups of structures have fairly flat roadbeds supported by piers. I am puzzled why one set of structures is called bridges and the other viaducts.

The main difference seems to be that the bridges are crossing a body of water while the viaducts are crossing an obstacle on land. This doesn’t feel like the answer, though. I’ve walked over 50 bridges in Pittsburgh, the majority of which are over land. Not one of these structures is called a viaduct. To help find clues to solve this puzzle, I looked up the definitions of bridge and viaduct.

Merriam-Webster’s definitions are not much help:

Viaduct: a long elevated roadway usually consisting of a series of short spans supported by arches, piers, or columns

Bridge: a structure carrying a pathway or roadway over a depression or obstacle

The Oxford English Dictionary has similar definitions:

Viaduct: an elevated structure consisting of a series of arches or spans, by means of which a railroad or road is carried over a valley, road, river, or marshy low-lying ground

Bridge: a structure forming or carrying a road, path, or (in later use) a railroad, etc., which spans a body of water, a roadway, a valley, or some other obstacle or gap, and allows a person or vehicle to pass unimpeded over or across it

Based on these definitions, the features that seem to distinguish a viaduct from a bridge are elevation and short spans. This still doesn’t help solve the question of why the Grant Park structures are viaducts and the Chicago River structures are bridges.

Next, I turned to “How to Read Bridges” by Edward Denison and Ian Stewart. The glossary defines viaduct as “a type of bridge over land formed by a series of small (usually arched) spans.” This definition seems to work best for the viaducts in Chicago. They are over land and have a series of spans, though the spans are not arched.

To further develop my understanding, I paged through the nine examples of viaducts in “How to Read Bridges.” All nine examples are elevated (such as the 330-foot high Goltzsch Viaduct and the 407-foot high Garabit Viaduct) and have multiple arches or piers (such as the 21-arch Glenfinnan Viaduct, the 8-arch Wharncliffe Viaduct, and the 5-pier Busseau Sur Grusse Viaduct). All, but one, have no support system above the road deck. The exception is the Millau Viaduct, which uses a cable-stayed deck on top of seven piers that range from 253 feet to 800 feet tall. All, but one, are over land. The Garabit Viaduct spans the Truyère Valley and one-third of its length crosses the Truyère River. In another example, the approaches to the Cubzac-les-Ponts over the River Dordogne are considered viaducts, but it is a bridge that crosses the river.

I find myself again at a loss. While the definition in this book seems to work for the Chicago viaducts, the examples do not look like the Chicago structures. To help the Chicago viaducts fit in, I propose a new definition built from the three definitions and nine examples above:

Viaduct: an elevated roadway, supported by many arches or piers over land.

Yet, there are exceptions to every rule. The nine examples in “How to Read Bridges” include exceptions to the support system of the viaduct and to the obstacle spanned by a viaduct. Expanding upon this, the Chicago viaducts, which are supported by multiple piers over land, become the exception to the elevated part of the rule or definition.

My biggest take away is that it is no easier to define a viaduct than it is to define a bridge. In most cases, as with bridges, a viaduct is something you know when you see it, even if you cannot define it. However, sometimes it takes a label or a sign, such as the maps of Chicago’s viaducts and, prior to its restoration, the maps of Heth’s Run Bridge, to know what you are seeing.

In Search of Roebling

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Last summer’s search for Roebling bridges (see Market St, Steubenville and Wheeling Suspension Bridge) came to a successful end as a golden sunset spread over Cincinnati.  The reason we struck out earlier in the day is that the Cincinnati-Covington Bridge is one of the two remaining Roebling suspension bridges.  The other is, of course, his most famous bridge: the Brooklyn Bridge.  The first of Roebling’s five suspension bridges was built in Pittsburgh at the site of the current Smithfield Street Bridge, but lasted less than 40 years before the increased river and road traffic made it obsolete.

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Between Roebling’s two remaining bridges, I found the Cincinnati bridge more appealing.  Its character feels like it would fit right in on the Thames in London.  I also appreciated the engaging green spaces at either end.  The birds liked this bridge, too.

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Sunset from the Roebling Bridge

 

 

 

Brooklyn Bridge

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Yesterday, as I was writing my post about the Wheeling Suspension Bridge by Roebling’s competitor, I was fascinated to discover that I never wrote a post about my walk across the Brooklyn Bridge. I decided to rectify the situation. The more I worked on it; the more fascinated I became. At this point, nearly 5 years after having walked it, all I can surmise is that I must have been very tired and/or hungry while crossing it.

In my post on the Manhattan Bridge, I mention how much more I liked that bridge than the Brooklyn Bridge. I can remember how much more thought provoking I found the Manhattan Bridge, but in looking back at my photos, I am shocked at how uninspiring I found the Brooklyn Bridge. I think it may hold the record for the fewest number of photos I’ve taken of any of the bridges I have walked. Especially, if we look at number of photos versus the length of the bridge. I suppose there may have been some other factors such as the construction zone on parts of the bridge.

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Another factor may have been the fact that the walkway is in the center of the bridge and above level of the traffic. While I remember this as a highlight and an intriguing part of the bridge, I also seem to recall that it may have caused interference with framing any potential photos.

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I will take back some of my comments on the Wheeling Suspension Bridge. While both bridges do have a lot of structural parts holding them up, those of the Wheeling bridge were much more fascinating. This may in part have been because you were able to get up close with them.

Below are the views of the surroundings. On one side you have the Manhattan Bridge and on the other the Statue of Liberty. That is just about the extent of the photos I took from the Brooklyn Bridge.

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I feel that I ought to give this bridge a second chance. If/when I ever make it back to New York City, I think I will have to walk it again (maybe after a good meal). The problem here is that my last trip there in 2012 when I first walked the bridge confirmed for me that New York is really not the city for me and I have no plans to make a trip back anytime soon.

 

Wheeling Suspension Bridge

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Wheeling Bridge - straight on

I had a blast with the Wheeling Suspension Bridge.  First, I was fascinated by how it was squeezed between the buildings on the mainland side.  Second, as an early suspension bridge, it has many parts to ensure that it would stay up, which provided more than the average opportunity to attempt to be artistic in photographing it.

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The Wheeling Suspension Bridge was the largest suspension bridge in the world when it was built.  Charles Ellet won the competition to design the bridge over John Roebling.  There are some similarities in style between this bridge and Roebling’s Brooklyn Bridge with the stone piers and suspension ropes.  Before we walked across this one and read the plaque, we were under the impression that it was a Roebling bridge.

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Wheeling has two different trends of riverfront uses than those found in Stuebenville.  On one side of the river (island side), is riverfront housing of surprisingly old construction.  On the other side (city side), is a modern riverfront park with bike trail.

Riverfront homes
Riverfront park