Bollman Truss Railroad Bridge: Difference between revisions
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==External links== |
==External links== |
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*[http://users.erols.com/rmayes/savage.html Color images of the Bollman Bridge after preservation work] |
*[https://web.archive.org/web/20060408094216/http://users.erols.com:80/rmayes/savage.html Color images of the Bollman Bridge after preservation work] |
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*[http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=957811596&ResourceType=Structure National Historic Landmark information] |
*[https://web.archive.org/web/20070211034834/http://tps.cr.nps.gov:80/nhl/detail.cfm?ResourceId=957811596&ResourceType=Structure National Historic Landmark information] |
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*[http://www.asce.org/history/brdg_bollman.html American Society of Civil Engineers - Bollman Truss Bridge] |
*[https://web.archive.org/web/20051111201619/http://www.asce.org:80/history/brdg_bollman.html American Society of Civil Engineers - Bollman Truss Bridge] |
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*{{Structurae |id=s0000348 |title=Bollman Truss Bridge}} |
*{{Structurae |id=s0000348 |title=Bollman Truss Bridge}} |
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*[http://www.co.ho.md.us/RAP/RAP_HoCoParksSavage.htm Savage Park] |
*[https://web.archive.org/web/20060328031746/http://www.co.ho.md.us:80/RAP/RAP_HoCoParksSavage.htm Savage Park] |
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*[http://www.du.edu/~jcalvert/tech/bolltrus.htm History and analysis of the Bollman truss] |
*[http://www.du.edu/~jcalvert/tech/bolltrus.htm History and analysis of the Bollman truss] |
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*{{MHT url|id=101|title=Bollman Suspension Truss Bridge, Howard County}}, including photo in 1985, at Maryland Historical Trust |
*{{MHT url|id=101|title=Bollman Suspension Truss Bridge, Howard County}}, including photo in 1985, at Maryland Historical Trust |
Revision as of 15:07, 5 November 2016
Bollman Suspension and Trussed Bridge | |
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![]() Bollman Bridge with Savage Mill tower in background, 1970 | |
Coordinates | 39°08′05″N 76°49′31″W / 39.1347°N 76.8253°W |
Carries | Savage Mill Trail |
Crosses | Little Patuxent River |
Locale | Savage, Maryland[1] |
Characteristics | |
Design | Bollman Truss[1] |
Material | Cast and wrought Iron[1] |
Total length | 160 feet (48.8 m)[1] |
Longest span | 2 × 80 feet (24.4 m)[1] |
No. of spans | 2[1] |
Piers in water | 1 |
Load limit | 36 tons (72000 kips)[2] |
History | |
Designer | Wendel Bollman[1] |
Construction end | 1869[1] |
Location | |
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Bollman Suspension and Trussed Bridge | |
Location | Savage, Maryland |
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Area | 4 acres (1.6 ha) |
Built | 1869 |
Architect | Bollman, Wendal |
Architectural style | Other |
NRHP reference No. | 72000582[3] |
Added to NRHP | October 18, 1972[3] |
The Bollman Truss Railroad Bridge at Savage, Maryland is the sole surviving example of a revolutionary design in the history of American bridge engineering. The 160-foot (48.8 m) double-span truss bridge is one of the oldest standing iron railroad bridges in the United States; currently, however, it is in use carrying the Savage Mill Trail across the Little Patuxent River. It was the first successful all-metal bridge design to be adopted and consistently used on a railroad.[1] The type was named for its inventor, Wendel Bollman, a self-educated Baltimore engineer.
History
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1e/Bollman-bridge-2.jpg/220px-Bollman-bridge-2.jpg)
The bridge was built for an unknown location on the main line of the Baltimore and Ohio Railroad in 1852, and was moved to its present location, spanning the Little Patuxent River on the spur to the Savage Mill, in 1887. This spur line dates to around 1840 and originally crossed the river on a stone arch bridge; however, due to alterations to the mill in the 1880s and topographical restrictions, a replacement bridge was needed. The bridge remained in service until the mill closed in 1947; switching crews used additional cars in order to avoid crossing the bridge with locomotives, and thus there was never a need for a more substantial structure. A smaller, narrower example was installed adjacent to the railbridge for road traffic, which was torn down after WWI.[4]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Bollman_Truss_Bridge_Harpers_Ferry.jpg/220px-Bollman_Truss_Bridge_Harpers_Ferry.jpg)
It was the first successful all-metal bridge design to be adopted and consistently used on a railroad. The design employs wrought iron tension members and cast iron compression members. It was an improvement over wooden structures, as the independent structural units lessened the possibility of structural failure. Patented on January 6, 1852,[6][7] the company built about a hundred of these bridges through 1873. Their durability and ease of assembly greatly facilitated expansion of American railroads in this period. Bollman's Wells Creek Bridge has also survived, but it employs a different type of truss system.
Description
The Bollman Bridge is a two-span through-truss, resting on granite abutments at each end and a granite pier in the middle of the river. The truss structure is a mixture of wrought and cast iron. The truss configuration is the design patented by Bollman as the "Bollman suspension truss" in 1852. Each span is 79.5 feet (24.2 m) long, 25.5 feet (7.8 m) wide and about 21 feet (6.4 m) tall. The Bollman truss suspends the deck from a network of tension members, while the top chord resists compressive forces. The system is therefore referred to as a suspension truss.[8]
The truss includes decorative elements, such as Doric styled vertical members. The cast iron end towers, which bear transfer the weight of the structure to the abutments and pier, are also detailed. A decorative and protective metal enclosure at the top of the towers was lost to vandalism, but was replaced during the restoration work. Metal strips at each portal read "W. BOLLMAN, PATENTEE", "BALTIMORE, MD.", "BUILT BY B&O R.R. CO.", "1869" AND "RENEWED 1866". Replicas of the original strips were installed during the restoration.[8]
The bridge was brightly painted, using red oxide for the towers and the heavier compression members and an ivory color for the lighter tension members.[8] The bridge was originally painted in a three color scheme, documented in black and white photography, with specific shades unknown.[9]
Restoration
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/AERIAL_VIEW_OF_BRIDGE_FROM_EAST_-_Baltimore_and_Ohio_Railroad%2C_Bollman_Truss_Bridge%2C_Spanning_Little_Patuxent_River%2C_Savage%2C_Howard_County%2C_MD_HAER_MD%2C14-SAV%2C1-1.tif/lossy-page1-220px-thumbnail.tif.jpg)
In 1966 the American Society of Civil Engineers introduced a new program, designating the bridge as the first-ever Historic Civil Engineering Landmark.[10] The bridge was listed on the National Register of Historic Places on December 18, 1972, and was designated a National Historic Landmark on February 16, 2000. The bridge was surveyed for restoration in 1978 by Modjeski and Masters with deterioration of the floor trusses noted. A $214,200 restoration contract was let to Dewey-Jordan of Frederick in September 1982.[9] The bridge was restored by Wallace, Montgomery & Associates, LLP, for the Howard County Department of Recreation and Parks in 1983, and more recently underwent additional preservation work and was rededicated on September 16, 2000. Today it receives regular maintenance as part of Savage Park. Nearby Bollman Bridge Elementary School takes its name from the historic bridge.
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Existing bridge, 1982 (prior to 1983-84 rehabilitation work by WM&A)
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Upper cords of the existing structure, 1982
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View through the existing bridge, 1982
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Elevation of The Bollman Truss following rehabilitation by WM&A, 1984
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Partial elevation, 1984
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Pier elevation, 1984
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Lower cords, 1984.
See also
- List of bridges documented by the Historic American Engineering Record in Maryland
- List of bridges on the National Register of Historic Places in Maryland
- List of Howard County properties in the Maryland Historical Trust
References
- ^ a b c d e f g h i Jackson, Donald C. (1988). Great American Bridges and Dams. Wiley. pp. 121–122. ISBN 0-471-14385-5.
{{cite book}}
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(help) - ^ "Structural Systems of the Bollman Truss Bridge at Savage, Maryland" (PDF). Retrieved 2012-01-31.
- ^ a b "National Register Information System". National Register of Historic Places. National Park Service. July 9, 2010.
- ^ Howard County Historical Society. Images of America Howard County. p. 117.
- ^ Digital Collections, The New York Public Library. "(still image) Harper's Ferry. B.&O. R.R." The New York Public Library, Astor, Lennox, and Tilden Foundation. Retrieved December 19, 2015.
- ^ US 8624 Suspension bridge
- ^ Bollman, Wendel (1852-01-06). "Construction of bridges". Google. Retrieved 2008-09-01.
- ^ a b c Caplinger, Michael W. (July 16, 1999). "National Register of Historic Places Nomination: Bollman Truss Railroad Bridge". National Park Service. Retrieved 2009-03-18.
- ^ a b DeLony, Eric (1996). "The Bollman Bridge at Savage, Maryland: Restoring America's Quintessential Metal Truss". APT Bulletin. 27 (1–2). JSTOR 1504496.
- ^ Historic plaque placed by the ASCE near the north end of the bridge. Observed April 27, 2007.
External links
- Color images of the Bollman Bridge after preservation work
- National Historic Landmark information
- American Society of Civil Engineers - Bollman Truss Bridge
- Bollman Truss Bridge at Structurae
- Savage Park
- History and analysis of the Bollman truss
- Bollman Suspension Truss Bridge, Howard County, including photo in 1985, at Maryland Historical Trust
- Historic American Engineering Record (HAER) No. MD-1, "Baltimore & Ohio Railroad, Bollman Truss Bridge, Spanning Little Patuxent River, Savage, Howard County, MD", 20 photos, 7 measured drawings, 8 data pages, 4 photo caption pages
- Baltimore and Ohio Railroad bridges
- Bridges in Howard County, Maryland
- Railroad bridges in Maryland
- Truss bridges in the United States
- Bridges completed in 1869
- Historic Civil Engineering Landmarks
- Railroad bridges on the National Register of Historic Places in Maryland
- Railroad-related National Historic Landmarks
- National Historic Landmarks in Maryland
- Historic American Engineering Record in Maryland
- 1852 establishments in Maryland
- Relocated buildings and structures in Maryland
- National Register of Historic Places in Howard County, Maryland