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Bath Bridge 29-05-03

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Photos 

Photo taken by Historic American Engineering Record

View photos at Library of Congress

Map 

Street View 

Analysis of significance and history 

Written by Michael Quiet

This bridge, one of the longest (in total length) covered bridges left in the country, is a true gem of the covered bridge community. Despite its age, the bridge still manages to retain a good amount of historical integrity (with most of the significant changes that have been done now being old enough to be historical in their own right), this bridge is also notable because of its age, length, unusual truss configuration, as well as its beautiful setting in the downtown of historic Bath, N.H.

The Bath Bridge was first constructed in 1832, although this is some times questioned as there was an earlier structure at this site. An examination of its stone abutments and also the truss configuration indicate that it was originally a 3 span system, with two larger spans and a smaller span sandwiched in the middle.

The truss system employed is very unique, and deserves a good amount of attention. This truss has been sometimes classified as a Burr arch variation, or erroneously identified as either a Paddleford or Haupt truss (both types this bridge predate). In truth its neither, and does not conform to any standard truss type. A arch (similar to a Burr type) runs across the 3 original spans, and the main truss is comprised of diagonal elements sloped towards the center of the span, running across two vertical elements and terminating in the upper chord.

Information such as the bridge wright or any other information about this truss type have been lost to time, so we have no idea who built this or the reasons why such a unusual truss type was devised. The most likely explanation was a creative bridge wright working to avoid patent royalties for the more common truss types. An interesting note is that there is another example of this bridge type existing nearby in Thetford Vermont (see the Sayres Covered Bridge, commonly mis-identified as a Haupt Truss)

In the first few decades of the 20th century, as with most of the covered highway bridges in New Hampshire, this bridge was modified to increase its load capacity with the addition of laminated wooden arches. From east to to west, a arch was added with no modification to the first and second span, which doesn't distract terribly from the original configuration. The third span had some unusual modifications made, due in part to the fact that the Boston & Maine railroad ran under the 3rd span. A pier was made midway through the span, and a third arch connects the 2nd pier to this pier. For the remainder of the bridge there is no added arch, instead 3 wooden piles support the remainder of the truss. Inside the truss this creates an inconsistent look which mildly detracts from the experience.

The bridge is well taken care of, having received rehabilitation's over the years as needed (the most recent being 2013-14). Its important that this bridge continue to receive this level of care, as its quite special due to the aforementioned points. Its also notable as a survivor among covered bridges, as both longer spans and "in-town" bridges were the most susceptible to replacement over the years due to higher traffic/weight needs.

Facts 

Overview
Covered bridge over Ammonoosuc River on West Bath Road in Bath
Location
Grafton County, New Hampshire
Status
Open to traffic
History
Built 1832; rehabilitated 1987; rehabilitated 2013-14
Builder
- Wright Construction (2014 Rehabilitation)
Design
Covered through truss with added arches
Dimensions
Length of largest span: 86.9 ft.
Total length: 375.0 ft.
Deck width: 17.4 ft.
Vertical clearance above deck: 8.9 ft.
Recognition
Posted to the National Register of Historic Places
Approximate latitude, longitude
+44.16667, -71.96694   (decimal degrees)
44°10'00" N, 71°58'01" W   (degrees°minutes'seconds")
Approximate UTM coordinates
19/262791/4894665 (zone/easting/northing)
Quadrangle map:
Lisbon
Inventory number
BH 24932 (Bridgehunter.com ID)
Inspection (as of 10/2015)
Deck condition rating: Excellent (9 out of 9)
Superstructure condition rating: Good (7 out of 9)
Substructure condition rating: Fair (5 out of 9)
Sufficiency rating: 23.1 (out of 100)
Average daily traffic (as of 2014)
310

Update Log 

  • August 24, 2016: New photos from John Loxton
  • January 13, 2016: New photos from Mike Garland
  • September 5, 2015: New photos from John Loxton
  • May 16, 2015: Updated by Will Truax: Corrected name - In that the name listed here is / was in use no where else
  • May 12, 2015: Essay added by Michael Quiet
  • July 7, 2014: New Street View added by Ralph Demars
  • May 12, 2014: Updated by Michael Quiet: Noted that bridge is currently closed for rehabilitation
  • January 16, 2014: Updated by Tony Dillon: Corrected truss type
  • October 21, 2013: Photo imported by Dave King
  • October 26, 2011: Photos imported by Jason Smith

Sources 

  • HAER NH-34 - Bath Bridge, Spanning Ammonoosuc River, Lisbon Road, Bath, Grafton, NH
  • Tony Dillon - spansaver [at] hotmail [dot] com
  • Michael Quiet - mquiet [at] gmail [dot] com
  • Will Truax - Bridgewright [at] gmail [dot] com
  • John Loxton
  • Mike Garland - Rapier342 [at] comcast [dot] net

Comments 

Bath Bridge 29-05-03
Posted January 12, 2017, by Michael Norris (guardian1 [at] iprimus [dot] com [dot] au)

Does anyone know if there was any existing interior lighting within the covered bridge prior to the recent rehabilitation, and if there was, was it replaced or repaired?

If no existing lighting, then does anyone know if any interior lighting was installed at or around the time of the most recent rehabilitation, and if so, what date, and does it have sensor or timer to trigger its operation?

Bath Bridge 29-05-03
Posted May 16, 2015, by Will Truax (Bridgewright [at] gmail [dot] com)

I am in complete agreement with Micheal as to categorizing truss type -

The Bath features an unpatented truss type which was once found in greater numbers in this immediate area.

Though often misidentified as Burr or Haupt variants, the truss is not a variant of either, nor does it share any similarities with a Paddleford other than the curious irony that both share the same home range and both are unpatented.

West Bath Road Bridge
Posted November 8, 2013, by Randy Needham (RNeedham [at] AcrowUSA [dot] com)

Currently undergoing rebuilding with the intent to restore a 10-ton rating.