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Military Street Bridge

   


Military Street Bridge

Primary Photographer(s): Nathan Holth

Bridge Documented: July 17, 2003
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Key Facts

Facility Carried / Feature Intersected
Military Street (BL 69/94) Over Black River
Location
Port Huron: St. Clair County, Michigan

Technical Facts

Rehabilitation Date
Not Available or Not Applicable
Main Span Length
82.5 Feet (25.1 Meters)
Structure Length
140 Feet (42.7 Meters)
Roadway Width
40 Feet (12.2 Meters)
Spans
1 Main Span(s)
NBI Number
Not Applicable

Historic Significance Rating (HSR)

Bridge Documentation

This Bridge No Longer Exists!

View Archived National Bridge Inventory Report - Has Additional Details and Evaluation

View Historic American Engineering Record (HAER) Documentation For This Bridge

HAER Data Pages, PDF

View The Original Plans For the 1914 Historic Bridge (Also Includes Elevation Drawing of Replacement Bridge)

The Historic 1914 Bascule Bridge Was Demolished and Replaced By MDOT In 1990!

At the time of demolition, the historic Military Street Bridge was the oldest bascule bridge in Michigan and it was also noted for its gorgeous ornate railings. These railings are what HistoricBridges.org describes as "arched lattice railing". These railings follow a general pattern of arched lattice on the top of each panel, with a row of traditional lattice in a smaller lower section of the panel. The exact design varies from bridge to bridge and the railings were not a product of a particular bridge company, and they appear on a vast variety of bridges from the late 19th century into the early part of the 20th Century. That said, railings of this style are also very rare today. The historic Military Street Bridge also featured wooden walkways on each side, a feature once seen on all three of the Port Huron bascule bridges, but now present on none of Port Huron's bridges.

In 1990, a replacement project demolished this historic bridge. A disgrace to the Section 106 process, mitigation for the adverse affect of demolishing this bridge did not include the storage and/or preservation of even a single panel of the elegant railings, which would have been an obvious form of mitigation. Unfortunately, the historic Military Street Bridge was demolished before HistoricBridges.org existed, and as such, HAER is the main source for photos of this bridge. Additionally, James Colo, who was project manager for the replacement of the bridge discovered the original builder plaque hidden under layers of paint on one of the bridge girders and saved it from being scrapped. A photo of the plaque is shown on this page.

The Military bridge is the latest in a long history of spans at this location. One of these earliest spans was a wooden swing bridge dating to around the 1850s. The next span was a beautiful pin-connected metal through truss swing bridge which appears to have been built by the Smith Bridge Company of Toledo, Ohio based on the design of the portal bracing, plaque, and finials. The through span gave Port Huron a beautiful gateway into the city. The next span was the 1914 two leaf bascule bridge with the ornate railings. It also had attractive overhead "trolley arches" to hold the electric lines for the trolleys. These arches were removed in the 1950s. This bridge was the one the current 1991 span replaced. 

The 1914 bascule bridge was highly significant both historically and technologically. It was the oldest highway bascule bridge in Michigan at the time of demolition. It also was a rare example of a Strauss trunnion bascule bridge. Designed by famous engineer Joseph Strauss, the design included a main trunnion as well as a counterweight trunnion. Many Strauss bascule bridge designs put the counterweight over the roadway, but this more aesthetically pleasing design concealed the counterweight below the deck. Designed in 1912, this bridge was among the earliest surviving examples of a bridge designed by Joseph Strauss.

When the current span was built, MDOT was responsible for the monetary responsibilities, since the bridge was located on an Interstate Business Loop. All the latest in technology was used to build this highly computerized and hydraulics powered bridge. All of this fancy stuff was supposed to make the bridge better than the old bridge. However, the new bridge has caused problems ever since the bridge was put into service. Sometimes when it got hot in the summer, they would have fireman come and hose the bridge down to keep it cool enough to operate (by causing the metal to shrink)! Leading up to 2014, even though the bridge was only a few decades old, the bridge's poor construction quality already showed up in bridge inspection findings. In the National Bridge Inventory, the bridge's superstructure dropped down to  "Fair" which is 5/10. This is a very rapid decline in superstructure condition. The bridge was apparently also not designed to provide for the traffic needs of the area, and the bridge has already been classified as functionally obsolete. The bridge's sufficiency was prior to rehabilitation only 54.6%, again extremely low for a bridge this young. Requests can often be made for total replacement funds when a bridge's sufficiency drops below 50%.

It should also be noted that even under normal operation, the bridge raises and lowers more slowly than most historic double-leaf bascule bridges that still operate under traditional electric motor. A good example would be in Chicago where bridges on the busy Calumet River can be raised in as little as 40 seconds. This bridge in Port Huron definitely cannot raise that quickly. This is partially due to the bridge's rolling lift design which cannot raise as quickly, whereas the previous bridge and the bridges in Chicago are fixed trunnion design. The rolling lift type was chosen for the replacement bridge to meet the clearance requirements for the location. When a rolling lift bascule is raised, it rolls back on a track which has the side effect of moving the leaves further back away from the river, thus increasing space for navigation. Thus, the rolling lift design met the needs for navigation, while reducing the footprint of the bridge which had to be fit in a very limited space right in the heart of downtown Port Huron.

So what of the 2014-2015 rehabilitation? If you think that fixed the bridge's problems think again. After rehabilitation (which included a complete overhaul of the ever-troublesome hydraulic operating equipment) the bridge reopened to traffic in March of 2015. However, apparently a few details were overlooked. The bridge closed in April for replacement of a hydraulic hose. The bridge closed again in July 2015 expectedly when there was "an issue with the hydraulic system" according to MDOT. It turned out the hydraulic motor had failed and needed to be replaced. As of this writing in July 2015, MDOT already is planning yet another closure to (big surprise) "replace hydraulic hoses."

Given the constant problems this bridge has had, a few questions arise. Why didn't MDOT just rehabilitate the historic bridge designed by a world renowned engineer? Why didn't MDOT stick with the tried and true, reliable method of operating a bascule bridge using a simple electric motor connected to a series of gears? This system is what keeps Chicago's many historic bridges raising quicker and more reliably even today after decades of use. And the final question, what has this world come to when all of today's engineers and computers cannot design something that works as reliably as a bridge designed by hand in the early 20th century? They sure don't build them like they used to!

HistoricBridges.org did arrange a tour of the current Military Street Bridge, which, like any movable bridge is a lot more than just a span over a river and has a lot of mechanical equipment that is not out in the open for anyone to see. These photos are presented for comparison to the operation of historic bascule bridges such as the Seventh Street Bridge. The equipment and controls that operate a modern bascule are vastly different from historic bascule bridges.

 

Above Left: The first known bridge at this location. Above Right: The second known bridge at this location.

 

Above: The third known bridge at this location.

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Photos and Videos: Military Street Bridge

Available Photo Galleries and Videos

Click on a thumbnail or gallery name below to visit that particular photo gallery. If videos are available, click on a video name to view and/or download that particular video.

 
View Photo Gallery
1914 Bridge Photos
Original / Full Size Photos
A collection of photos showing the previous, historic bridge at this location. For the best visual immersion and full detail, or for use as a desktop background, this gallery presents the photos for this bridge in the original digital camera resolution.
View Photo Gallery
1991 Bridge Virtual Tour
Original / Full Size Photos
This special photo gallery is a rare look at the inside of the interior of the bridge including the bridge tender house and tail pit of the bridge. It makes a good comparison to the interior of historic bascule bridges. For the best visual immersion and full detail, or for use as a desktop background, this gallery presents the photos for this bridge in the original digital camera resolution.
View Photo Gallery
1914 Bridge Photos
Mobile Optimized Gallery
A collection of photos showing the previous, historic bridge at this location. View the photos for this bridge in a reduced size which is useful for mobile/smartphone users, modem (dial-up) users, or those who do not wish to wait for the longer download times of the full-size photos. Alternatively, view this photo gallery using a popup slideshow viewer (great for mobile users) by clicking the link below.
Browse Gallery With Popup Viewer
View Photo Gallery
1991 Bridge Virtual Tour
Mobile Optimized Gallery
This special photo gallery is a rare look at the inside of the interior of the bridge including the bridge tender house and tail pit of the bridge. It makes a good comparison to the interior of historic bascule bridges. View the photos for this bridge in a reduced size which is useful for mobile/smartphone users, modem (dial-up) users, or those who do not wish to wait for the longer download times of the full-size photos. Alternatively, view this photo gallery using a popup slideshow viewer (great for mobile users) by clicking the link below.
Browse Gallery With Popup Viewer
View Video
1991 Bridge Being Raised
Full Motion Video
Streaming video of the bridge. Also includes a higher quality downloadable video for greater clarity or offline viewing.
View Video
1991 Bridge Being Lowered
Full Motion Video
Streaming video of the bridge. Also includes a higher quality downloadable video for greater clarity or offline viewing.

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