HistoricBridges.org Menu: HistoricBridges.org Menu:

Divider

Note: We are currently testing a redesign of the Bridge Browser individual bridge pages. Everything should still work, but some bugs and visual problems may occur. We hope to have this resolved soon.

HistoricBridges.org: Bridge Browser

Advertisements:
Bach Steel - Experts at historic truss bridge restoration.

Divider

Sarah Mildred Long Bridge

   
                  



Sarah Mildred Long Bridge
Bridge Documented: June 15, 2012

Primary Photographer(s): Nathan Holth

View Photos
and Videos
View Maps
and Links

Key Facts

Sarah Mildred Long Bridge

Facility Carried / Feature Intersected
US-1 Bypass and Railroad (Boston and Maine) Over Piscataqua River
Location
Portsmouth and Kittery: Rockingham County, New Hampshire and York County, Maine
Construction Date and Builder/Engineer
1940 By Builder/Contractor: Phoenix Bridge Company of Phoenixville, Pennsylvania and Engineer/Design: Harrington and Cortelyou
Rehabilitation Date
1991
Structure Type
Metal 8 Panel Rivet-Connected Warren Deck Truss, Movable: Vertical Lift (Tower Drive) and Approach Spans: Metal Deck Girder, Movable: Retractile
Structure Length
2804 Feet (854.7 Meters)
Main Span Length
227 Feet (69.2 Meters)
Roadway Width
30 Feet (9.1 Meters)
Main Spans
1
Approach Spans
26
NBI Number
021702510010800

Historic Significance Rating (HSR)

Bridge Documentation

This Bridge's Future Is At Risk!

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

This is a very unique bridge. It is a double-deck bridge, with the top level carrying a highway and the lower level carrying a railroad line. Double-deck bridges are rare, nationwide. The main span of the bridge is a vertical lift bridge of unusual appearance. The unusual appearance is because bridges from this period usually had lift towers that were trussed, and often were broader at the base. However, this bridge has towers that on the sides are metal plate giving them a solid appearance. The towers also maintain the same width from top to bottom. The bridge has an extremely long and complex approach system consisting of deck truss and deck plate girder spans. The deck plate girder spans appear to have structurally separate load-bearing superstructures, one for the highway level and one for the railroad level. In contrast, the truss spans have one unified superstructure... each truss web supports both the upper and lower level. The railroad deck of the bridge ends sooner than the highway bridge at each end because the highway, being on the upper deck, must continue to pass over the railroad tracks until they curve away, and also the highway, being on the upper deck, has to have enough additional approach spans to bring the road back to ground level. Finally, perhaps the rarest and most unusual detail of the bridge is that one of the deck plate girder spans for the railroad is an example of one of the rarest general movable bridge categories: a retractile span. The deck plate girder span lifts up and slides back on top of an adjacent truss span. This span is kept retracted unless a train is coming. The retractile span itself is unusual and significant in its own right. It is also unusual for a single bridge structure to have two movable spans. Normally only one movable span is provided, usually in the center of the bridge where the main navigation channel is.

Information and Findings From Maine's Historic Bridge Inventory

Discussion of Bridge

The 1940 vertical lift bridge designed by Harrington & Cortelyou (Harrington was formerly associated with J.A.L. Waddell and is credited as being the mechanical engineer responsible for the development of the vertical lift bridge type) of Kansas City. Its design reflects mid-20th century refinements in the vertical lift bridge type, most notably the arrangement of the operating system with the drive motors and synchronous motors located at the top of the towers. It is the only vertical lift bridge in Maine with this operating arrangement. The bridge also has handsome, Art Moderne detailing. It was named in 1980 for Sarah Mildred Long, the longtime interstate bridge commission's secretary. The 1940 vertical lift bridge is judged to have high preservation priority because of the technological significance of the arrangement of the operating machinery.

Bridge Considered Historic By Survey: Yes

Divider

Photos and Videos: Sarah Mildred Long 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
Bridge Photo-Documentation
Original / Full Size Photos
A collection of overview and detail photos. 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
Bridge Photo-Documentation
Mobile Optimized Gallery
A collection of overview and detail photos. 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 Maps
and Links

Divider
 
Home Top

Divider

About - Contact

© Copyright 2003-2015, HistoricBridges.org. All Rights Reserved. Disclaimer: HistoricBridges.org is a volunteer group of private citizens. HistoricBridges.org is NOT a government agency, does not represent or work with any governmental agencies, nor is it in any way associated with any government agency or any non-profit organization. While we strive for accuracy in our factual content, HistoricBridges.org offers no guarantee of accuracy. Information is provided "as is" without warranty of any kind, either expressed or implied. Information could include technical inaccuracies or errors of omission. Opinions and commentary are the opinions of the respective HistoricBridges.org member who made them and do not necessarily represent the views of anyone else, including any outside photographers whose images may appear on the page in which the commentary appears. HistoricBridges.org does not bear any responsibility for any consequences resulting from the use of this or any other HistoricBridges.org information. Owners and users of bridges have the responsibility of correctly following all applicable laws, rules, and regulations, regardless of any HistoricBridges.org information.