HistoricBridges.org Menu: HistoricBridges.org Menu:

Divider

HistoricBridges.org: Bridge Browser

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

Divider

Alexandra Bridge

Interprovincial Bridge

   


Alexandra Bridge

Primary Photographer(s): Nathan Holth and Rick McOmber

Bridge Documented: April 13, 2011
View Photos
and Videos
View Maps
and Links

Key Facts

Location
Ottawa and Gatineau: Ottawa City, Ontario and Outaouais, Québec
Structure Type
Metal Cantilever 18 Panel Pin-Connected Pratt Through Truss, Fixed and Approach Spans: Metal 8 Panel Pin-Connected Pennsylvania Through Truss, Fixed
Construction Date and Builder / Engineer
1900 By Builder/Contractor: Dominion Bridge Company of Montréal, Québec

Technical Facts

Rehabilitation Date
2010
Main Span Length
555.75 Feet (169.4 Meters)
Structure Length
1857 Feet (566 Meters)
Roadway Width
62 Feet (18.9 Meters)
Spans
3 Main Span(s)
NBI Number
Not Applicable

Historic Significance Rating (HSR)

Bridge Documentation

View detailed historical articles discussing bridge construction from Transaction of The Canadian Society of Civil Engineers

View historical articles from Engineering Record discussing this bridge.

The Alexandra Bridge was originally the named the Interprovincial Bridge and officially renamed "Royal Alexandra Bridge" only a year later. The bridge is a magnificent heritage bridge that spans the Ottawa River right next to the center of Canadian government, Parliament Hill. Parliament Hill and Alexandra Bridge each offer spectacular views of each other. It is also next to where the Rideau Canal, a World Heritage site, connects to the Ottawa River. In a setting with such rich heritage and iconic structures, this bridge is an essential element of the area and it contributes greatly to the rich heritage and culture found here. The bridge has been honored by the Canadian Society for Civil Engineering as a National Historic Civil Engineering Site.


Early View of Bridge From Parliament

Source: William James Topley/Library and Archives Canada/PA-008917

 Aside from the iconic geometric beauty formed by its trusses, the bridge is historically and technologically significant as an extremely early surviving example of a large-scale cantilever truss bridge that represented a significant engineering achievement when completed. There are only a very small number of surviving cantilever truss bridges in North America that are older than this bridge. It was especially noteworthy in the context of Canada because it was designed and erected by Canadians without assistance of firms outside the country.


Alexandra Bridge In Its Early Years. View Showing Deck Layout.

Source: William James Topley/Library and Archives Canada/PA-009430 

A bridge with more than just a truss as a cantilever, the deck of this bridge is extremely unusual because it includes a design where the floorbeams are cantilevered far out beyond the truss lines to provide lanes originally for both vehicular and electric rail, while the traditional roadway space between the trusses was reserved for steam rail. This feature is particularly unusual because it is an original design feature of the bridge. This sort of deck expansion is sometimes added to a bridge in later years, usually with deck trusses. With most original designs for through truss bridges, pedestrian sidewalks are usually the only things cantilevered out beyond the truss lines.


Cross Section of Bridge at Pier

Source: Engineering Record, Vol 44, 1901. Digitized By Internet Archive. 

As the handsome plaques mounted on the end posts indicate, this bridge was the work of the railways, specifically the Ottawa and Gatineau Railway and the Pontiac Pacific Junction Railway. These railways later became part of Canadian Pacific, but Canadian Pacific had nothing to do with the construction of this bridge, contrary to some online sources. As originally built, the bridge had substantial approach systems carrying the rail line up to the bridge. These have since been removed, and the bridge only carries vehicular and non-motorized traffic today.


Alexandra Bridge from Major's Hill Park. Railway approach system visible.

Source: William James Topley/Library and Archives Canada/PA-008909 

Today, the southern cantilevered deck section carries non-motorized traffic only. The northern cantilevered deck section carries westbound traffic, while the center section between the trusses carries eastbound traffic.

The bridge consists of a main cantilever structure, along with several approach spans, the most noteworthy of which are a Pennsylvania through truss span and a Pratt through truss span located west of the cantilever spans.


Drawing Showing Entire Bridge

Source: Waddell, J.A.L., Bridge Engineering Volume 1, 1916. Digitized By Internet Archive.

The design of the cantilever portion of the bridge includes not only a top chord that slopes upward to form a point or tower above the cantilever piers, but its bottom chord also slopes downward to form a point at the same location. This is a design detail that only some through truss cantilever bridges display, such as the Quebec Bridge. In the case of the Alexandra Bridge, the purpose of this was to reduce the height of the piers. By reducing the needed masonry, costs were reduced. It also had the effect of allowing the bridge to be built with a shorter tower above the deck.


Construction of Bridge

Source: Topley Studio / Library and Archives Canada / PA-013866 

The erection of the bridge was accomplished using a "traveler crane" which was a tower structure that ran along tracks and had cranes hanging from it which were used to put the steel pieces into place. The use of travelers was common for erection of bridges like this during this period in history, although the exact design of the custom-built travelers varied from bridge to bridge. The design of the traveler used for this bridge is shown below.


Erection Traveler Crane (Left) and Diagram Showing Erection of Bridge (Right)

Source: Engineering Record, Vol 44, 1901. Digitized By Internet Archive. 

The cantilever spans of this bridge follow a subdivided Pratt (Baltimore) truss configuration. The suspended span at the center of the bridge is a Pratt truss.

Construction of the bridge began in February 1898 and the bridge was carrying trains in December of 1900. One of the more noteworthy and unusual aspects of this bridge was the challenges which were overcome during construction. Work on the bridge continued even during terrible winters with ice filling the river including the unusual frazil ice crystals. Another very unusual challenge was a massive amount of sawdust, logs, and other debris from mills which had literally filled in a significant part of the river. This debris, which apparently compressed, along with logs and other obstacles, made installing some of the piers a significant challenge as workers had to excavate through this material to reach the bedrock below. All this debris sitting in the river caused gasses to accumulate in some areas, and sawdust explosions occurred during construction, although no injuries occurred.


Alexandra Bridge In Its Early Years

Source: William James Topley/Library and Archives Canada/PA-008971 

Divider

Photos and Videos: Alexandra 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
Structure Overview
Original / Full Size Photos
A collection of overview photos that show the bridge as a whole and general areas of the bridge. 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
Structure Details
Original / Full Size Photos
A collection of detail photos that document the parts, construction, and condition of the bridge. 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
Simple Truss Spans
Original / Full Size Photos
A collection of overview and detail photos of the two approach simple truss spans of the bridge. 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
Parliament
Original / Full Size Photos
Parliament Hill and the Alexandra Bridge go hand in hand, each an excellent viewing platform for each other. This being the case, it is appropriate to offer this gallery of the beautiful Parliament buildings which are impossible to ignore during a visit to the bridge. 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
Structure Overview
Mobile Optimized Gallery
A collection of overview photos that show the bridge as a whole and general areas of the bridge. 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
Structure Details
Mobile Optimized Gallery
A collection of detail photos that document the parts, construction, and condition of the bridge. 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
Simple Truss Spans
Mobile Optimized Gallery
A collection of overview and detail photos of the two approach simple truss spans of the bridge. 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
Parliament
Mobile Optimized Gallery
Parliament Hill and the Alexandra Bridge go hand in hand, each an excellent viewing platform for each other. This being the case, it is appropriate to offer this gallery of the beautiful Parliament buildings which are impossible to ignore during a visit to the bridge. 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
Crossing Into Gatineau
Full Motion Video
Streaming video of the bridge. Also includes a higher quality downloadable video for greater clarity or offline viewing.
View Video
Crossing Into Ottawa
Full Motion Video
Streaming video of the bridge. Also includes a higher quality downloadable video for greater clarity or offline viewing.

View Maps
and Links

Divider
 
Home Top

Divider

About - Contact

© Copyright 2003-2017, 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.