|BORIS RUGHAS, Aug 2021|
|Kevin Blair posted|
|1 of 16 photos posted by Bill Salton|
Dredging flotilla leaving Hamilton Harbour with tugs Lac Vancouver, Whitby, and Robinson Bay.
BridgeHunter-skyway points out that the floor supports are trusses rather than the usual rolled or built-up I-beams. The channel span is 495' (151m).
The original crossing of the harbor canal was a swing bridge. "In 1922, this was replaced by a single leaf Strauss heel-trunnion type bascule. An interesting story about this bridge is that in 1931 the canal was widened, and to accommodate this, a second bascule bridge was added at the other side of the canal to form a double leaf bascule bridge. On April 29, 1952, the freighter W. E. Fitzgerald collided with and destroyed one of the spans, which led to the design and construction of the existing lift bridge....The lift bridge was the longest and heaviest in Canada when completed. The lift span weight when completed was 2,100 tons. The bridge was designed for a single railway track of the Hamilton-Northwestern railway as well as a two lane roadway. In 1982, the tracks were removed, and the roadway was widened. The current weight of the lift span is 2200 tons (2000 tonnes). The bridge has a vertical lift capacity of of 110 feet (33.5 meters)." [HistoricBridges-lift]
The concrete bridge was added in 1985 [dbpedia] which allowed the 1958 bridge to be rehabilitated without reducing the traffic flow and then doubling the traffic capacity when the rehabilitation was completed. It carries the Queen Elizabeth Way (QEW) that connects Toronto, CA, with Niagara Falls, Fort Erie and the USA. I noticed these two bridges about a week ago when I studied the Garden State Skyway.
This is the post that motivated this research. Historic Bridges considers the 1985 bridge to be ugly. I don't think all concrete bridges are ugly.
|Neil Pichora posted|
Federal St. Laurent inbound to the harbor today.
|1 of 3 photos posted by Neil Pichora|
"This was the first large-scale application of cast-in-place prestressed concrete segmental construction in Ontario." [And you thought I had an adjective heavy writing style.]
Once the main pier was built using cranes, two form travelers were used to cantilever from that pier.
Post-stress tensioning was used in several dimensions. This diagram shows the tendons used in the longitudinal dimension. If I caught an earlier statement in the video correctly, they had to wait 48 hours after the concrete was poured before they could do the posttensioning. I'm surprised that the concrete obtained enough strength in just 48 hours to handle the stress of the tendon's tension. This additional 48 hours per each pair of segments explains why construction techniques quickly evolved from cast-in-place to lifting precast segments into place.