Many different types of engineers work in designing bridges to suit all of our different needs. From mechanical to civil and even materials engineers, many professionals work in creating better and safer bridges. Read the following articles to learn more about bridges and engineering.

•  Forces in Bridges 
•  Types of Bridges
•  Famous Bridges of the World
•  Bridge Disasters
•  Types of Engineering

Bridge Disasters

Engineers must be concerned about safety at all times.  Lives are at stake when bridges collapse so engineers must design bridges to withstand all kinds of weather conditions, ground types and loads.  While the goal is to have no design fail, engineers examine and learn from past mistakes to avoid such failures in the future.

• Hyatt Regency Walkway Collapse, Kansas City, Missouri (failed in 1981)
• Point Pleasant/Silver Bridge, Ohio River (failed 1967)
• Tacoma Narrows Bridge, Tacoma, Washington (failed in 1940)
• Falls View Bridge, Niagara Falls (failed 1938)
• Quebec Bridge, St. Lawrence River (failed 1907,1916)
• Tay Bridge, Scotland (failed in 1879)

Quebec Bridge Disasters

The Quebec Bridge suffered from two collapses one in 1907, and another in 1916. The first Quebec bridge was cantilever bridge with a length of 1800 feet over the St. Lawrence River. The company contracted to build the bridge were the Phoenix Bridge Company of Pennsylvania and the Quebec Bridge Company with Theodore Cooper as the designing engineer.¹

During the project, Cooper fell sick, and the rest of the project was overseen by Norman McLure. After the initial bridge drawing were completed, Cooper discovered that the actual bridge weight would exceed the original design by over 8 million pounds. During construction, McLure discovered two beams were misaligned and appeared to be bent. When he went to report the problem, the workers proceeded with the building of the bridge without permission which lead to the eventual collapse of the bridge. In the summer of 1907, the south arm collapsed killing 76 workmen.²

The next year, Ralph Mojeski was the engineer in charge and a new design was implemented. The new bridge would have a larger span, and was designed for heavier loads. This time calculations were rechecked and the bases made of a stronger material with larger dimensions. In the final stages of the project, while the center piece was lowered into place, one of the rocker arms failed and the center piece fell to the river killing 11 workmen.⁴

 

Second Quebec Bridge Collapse5

Shortly after the collapse, workers completed the bridge in 1917. Today, the Quebec bridge is still the largest cantilever bridge in world.⁶

For more information about the Quebec Bridge Disasters, visit: http://www.prep.mcneese.edu/engr/casestud/quebic/quebic1.htm http://www.archives.ca/05/0518/05180202/0518020202_e.html