Alexandra Bridge
The Alexandra Bridge, also known as the Interprovincial Bridge, is a steel truss bridge that spans the Ottawa River, connecting Sussex Drive in Ottawa, Ontario, to Des Allumettières Boulevard in Gatineau, Quebec, as one of five interprovincial crossings in Canada's National Capital Region.[1][2] Constructed between 1898 and 1900 by the Dominion Bridge Company and opened to traffic in spring 1901, it originally accommodated steam trains, electric trams, horse-drawn carriages, and pedestrians, evolving into a key commuter link over its more than 120-year lifespan.[3][4][5] Recognized as a structure of national historic importance for its engineering and role in regional connectivity, the bridge features a cantilever truss design with significant spans, though it has required extensive repairs due to structural deterioration from age and usage.[1][6] Closed to vehicular traffic from October 2023 to February 2025 for rehabilitation works, it reopened under restrictions including weight limits, pedestrian and cyclist access priorities, and nightly closures for maintenance, reflecting its end-of-service-life status.[7][8] The Government of Canada has approved replacement plans, with deconstruction and new construction targeted for 2028 onward, to ensure a sustainable, modern link promoting active transportation while preserving the site's iconic skyline presence.[5][8]History
Origins and Construction
The origins of the Alexandra Bridge trace to the late 19th century, when expanding rail networks across the Ottawa River necessitated a direct interprovincial connection between Ottawa, Ontario, and Hull (now Gatineau), Quebec. In 1896, lumber magnate and railway owner John Ross Robertson Booth proposed the bridge at Nepean Point to extend his Canada Atlantic Railway, which had recently reached Rideau Street in Ottawa, amid competition from other interests including the Hull Electric Railway's repeated bids for its own crossing between 1896 and 1898.[9][10] Construction commenced in February 1898 under the auspices of the Canadian Pacific Railway, which acquired the project, with engineering led by G. C. Dunn and fabrication by the Dominion Bridge Company of Montréal, Quebec.[6][11] The design featured a steel truss cantilever structure, incorporating Canada's longest such span at the time—177 metres (580 feet)—and utilized four barges to position steel beams during assembly, overcoming the river's challenging winter conditions.[5][12] Work progressed rapidly, enabling rail traffic by December 1900, though the full opening for combined rail, streetcar, and pedestrian use followed in 1901.[11] Initially named the Interprovincial Bridge to reflect its cross-border role, it was redesignated the Royal Alexandra Bridge in September 1901 during a visit by the Duke and Duchess of Cornwall and York, honoring Queen Alexandra, consort of King Edward VII.[6][11] This Canadian-engineered project exemplified early 20th-century advancements in bridge-building, prioritizing durability for heavy rail loads while accommodating multi-modal transport from inception.[1]Early Operations and Expansions
The Alexandra Bridge, initially known as the Interprovincial Bridge, opened to road traffic on March 5, 1901, following construction of its piers in 1898–1899 and erection of steel trusses in 1900.[9][13] Designed from inception as a multi-use structure, it featured a central single-track railway line flanked by two road decks for carriages and wagons, two pedestrian walkways, and provisions for streetcar tracks, accommodating both freight and passenger rail alongside vehicular and foot traffic across the Ottawa River.[9] The first test train crossed on December 12, 1900, using locomotives from the Ottawa, Northern & Western Railway, confirming structural integrity ahead of public use.[10][13] Rail operations commenced formally on April 22, 1901, with the Ottawa and North Western Railway initiating passenger service from Hull Station to Ottawa's Central Station (later Union Station), covering the span in approximately seven minutes; this included ceremonial runs with dignitaries and decorated trains, marking the bridge's role in interprovincial connectivity for the Canada Atlantic Railway system.[10][13] By 1902, it supported Canadian Pacific transcontinental trains, handling substantial freight and passenger volumes until shifts in rail infrastructure later in the century.[9] Pedestrian and carriage traffic integrated seamlessly from opening, with the first documented carriage crossing occurring on January 15, 1901, by local officials, though full public road access followed inspections.[13] Early expansions focused on enhancing rail and streetcar integration rather than structural overhauls. On July 25, 1901, the Hull Electric Railway launched streetcar service over dedicated tracks, facilitating commuter links between Ottawa and Hull (now Gatineau) until its discontinuation in 1946.[10] In December 1901, the Pontiac Pacific Junction Railway added a connecting curve to enable Aylmer-bound trains to access the bridge, expanding regional rail routing without altering the bridge's core design.[10] These additions, completed within the first year of operation, optimized traffic flow amid growing demand from industrial and urban expansion on both sides of the river, though no major truss or span extensions occurred in this period.[9] The bridge was renamed the Royal Alexandra Bridge in 1902, honoring Princess Alexandra, reflecting its established operational success.[9]Mid-20th Century Use and Modifications
During the mid-20th century, the Alexandra Bridge served as a vital interprovincial crossing for vehicular, pedestrian, and rail traffic between Ottawa and Hull (now Gatineau), accommodating post-World War II growth in automobile use amid the Gréber Plan's urban modernization efforts.[14] It handled freight trains operated by Canadian Pacific Railway alongside increasing road traffic, as passenger rail declined with suburbanization, until the opening of a new Ottawa station in 1966 redirected services.[15] [14] A significant incident in 1946 involved a fire sparked by an electric tram, which destroyed much of the north approach; while Canadian Pacific rails were rebuilt, interprovincial tram tracks were not restored, terminating electric streetcar service across the bridge.[14] In the 1950s, upgrades enhanced capacity for pedestrians and vehicles while retaining rail functionality, aligning with efforts to adapt infrastructure for modern automotive demands under the Gréber Plan.[14] Rail operations fully ceased by 1970, prompting removal of the tracks and full conversion to a road-and-pedestrian bridge, eliminating the mixed-use configuration that had persisted since its 1901 opening.[14] [15] This shift reflected broader mid-century trends toward prioritizing highways over rail in urban cores, though the bridge's truss structure required no fundamental redesign.[14]Engineering and Specifications
Structural Design
The Alexandra Bridge is a steel cantilever truss structure distinguished by its true-pin connections, making it the only true-pin cantilevered truss bridge in the Ottawa region. This design features anchor spans, cantilever arms extending from piers, and a central suspended span hung between the arms, enabling efficient load distribution over long distances but at the expense of elevated construction complexity, material usage, and susceptibility to corrosion at the pin joints.[1][16] The bridge comprises five spans totaling 575 meters in length, with the deck carried mid-truss height through the anchor and cantilever sections. Its central clear span measures 320 meters, ranking as the fourth longest cantilever span worldwide at the time of its 1900 completion. The truss configuration employs a subdivided Pratt (Baltimore) pattern in the cantilever portions, supplemented by approach spans including a Pennsylvania through truss.[17][18][11] Primary structural elements include riveted steel trusses and solid web girders supported on steel trestles, elevated above the Ottawa River on six piers of concrete and masonry construction. This assembly reflects early 20th-century Canadian engineering by the Dominion Bridge Company under engineer Guy C. Dunn, prioritizing span efficiency over modern welded alternatives.[1][18]Dimensions and Capacity
The Alexandra Bridge features a total structure length of 566 meters (1,857 feet) and a main span length of 169.4 meters (555.8 feet). Its roadway width is 18.9 meters (62 feet), accommodating vehicular traffic lanes alongside pathways for pedestrians and cyclists.[11]| Specification | Value |
|---|---|
| Total Structure Length | 566 m (1,857 ft) |
| Main Span Length | 169.4 m (555.8 ft) |
| Roadway Width | 18.9 m (62 ft) |