25 January 2010

Victoria's Johnson Street Bridge has Significant Heritage Value

The Johnson Street Bridge opened in 1924 and was designed by
Joseph Strauss.

Victoria Vancouver Island British Columbia - The Johnson Street Bridge in Victoria has significant heritage value because it has a unique bascule bridge system created by one of the most famous bridge designers in the world.
 
Joseph Strauss designed the Johnson Street Bridge, which was completed in 1924 at a cost of $918,000. Strauss patented and used the Strauss Bascule Bridge system to build the structure and it is one of the few bascule bridges left in North America.
 
The bascule-type bridge has one end that rises, while a counter weight lowers on the opposite end. The bridge has two separate bascules for the railway section and the highway section.
 
The counter weight block on the highway span is a hollow concrete structure and contains a number of smaller concrete weights that add up to more than 780-tons. It balances the 350-ton opening span.
 
The linkage is moved by two large racks which are driven by two 75 horsepower electric motors.
 
The main opening span is 148 feet in length and when in the open position is balanced over a 45-foot fixed span. The Strauss Bascule Company Ltd. prepared the design for the bascule spans and the operating machinery.
 
The superstructure of the bridge was fabricated in Walkerville, Ontario, and contains 100 tons of steel.
 
The City of Victoria engineering department built the sub-structure of the bridge, which required 10,000 cubic yards of concrete. The original deck of the bridge was made of wood timbers. In 1979, extensive repairs were made to the superstructure, which had become severely corroded.
 
Joseph Strauss also designed and built the Golden Gate Bridge in San Francisco between 1933 and 1937.
 
Richard Gilbert.