(
Bridge Hunter;
Historic Bridges;
HAER; see below for satellite)
WLE = Wheeling & Lake Erie Railway
Evidently it is called Benwood instead of Bellaire because B&O had
their yard on the Benwood, WV side. Also, the state line is on the Ohio side of the river, so most of the truss work is in West Virginia.
Note the "ramps" on the upstream side of the piers to breakup ice flows.
I saved a copy of the satellite images because of the nice shadows. I labeled these notes with bridgeArch as well as bridgeTruss because of the 1871 stone arch approach on the Bellaire, OH side. You can get a close look at sandstone arches without getting your feet wet. The route that used this approach has been abandoned.
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| C Hanchey, License: Creative Commons Attribution-NonCommercial (CC BY-NC) |
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Carl Venzke posted
Baltimore & Ohio Railroad, Benwood Bridge, Benwood, Marshall County, WV
Historic American Engineering Record c1968
John Slowikowski Also made Hollywood famous in the movie Unstoppable |
The trusses we see today are from a reconstruction completed in 1905.
The reconstruction started in 1893 by replacing spans 14 and 15 with wrought iron trusses. Work continued in 1900 using "soft open-hearth steel."
I learned while studying
the RR bridge at Metropolis, IL that the river men wanted a 700' navigation channel. The War Department wanted that width here, which would have required a 730' truss. The War Department would probably have agreed to the span of 589.48' that was obtainable by removing pier 11 and lengthening piers 10 and 12 per Fig 1. That option would have cost $253,500 (1905 dollars) more than using the existing masonry.
To achieve a 700' wide channel, a lot of pier work would have to be done in addition to the 730' truss adding $563,000 (1905 dollars) to the cost.
Since
- neither the War Department nor the shipping interests would help with the extra cost
- the railroad was already running heavier locomotives and freight cars on both sides of the river and their investment in the other spans was currently being wasted
- a July 14, 1862 Act of Congress approved the current pier locations
the railroad built trusses using the existing piers.
I wonder if this 300' navigation channel is now the skinniest on the Ohio River. The locks on the river have the standard width of 110'. It would seem that two-way traffic is still possible even with a narrow primary channel because the adjacent span was charted to be at least 220' wide.
They were allowed to use falsework under Span 12, but not under Span 11. So they built Span 11 as a cantilever span. Span 12 was designed to handle the stresses of being a dead-load shore arm for Span 11 during construction as well as a live-load simple truss after construction. After the falsework was constructed under Span 12, the old span was removed and the live-load was carried by the falsework. This kept vibrations out of Span 12 and the west half of Span 11 during construction. Span 10 was not strong enough to function as a shore arm. So they built an additional truss on the outside of Span 10 to function as the shore arm. The weight of Span 12 was more than enough to offset the weight of half of Span 11. But the temporary shore arm truss around Span 10 too light, so they added counterweights to the Pier 9 end of the temporary truss.
The top cord of the old Span 11 truss was used to hold a 40-ton traveler. Before the traveler lifted members from a barge below, they would lock it down in a strong position on the old truss. Even so, they had to add temporary wooden braces to ensure that strains in the old truss members did not exceed 16,000 lb. per sq. in. I added red rectangles to the construction figure below to highlight the tie bars that were added between the top cords of the trusses so that the shore arms could hold up their halves of Span 11 until the halves were joined in the center. The new Span 11 was built around the old span so that only a dead load was supported during construction.
Reviewed by Unknown
on
November 27, 2018
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