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)
Hyatt Regency Walkway Collapse
Built in 1978 in Kansas City Missouri, the Hyatt Regency Hotel consisted of a 40-story tower and conference facilities. "Floating walkways" or "skyways" were suspended walkways connecting the two sections in the second, third, and fourth floors. The skyways were suspended 50 feet above an open atrium. On July 17, 1981, 2000 people gathered on the walkways and the atrium floor to watch the dance contest on the atrium. At 7:05 pm, a crack was heard, and the 2nd and 4th level walkways collapsed, injuring 200 people and killing 114 others.1
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Hyatt walkway collapse2 |
The reason behind the collapse was simple, the rods holding the beams were not strong enough to hold the combined weights of the walkways and the people. Gillum-Colaco International Inc. (G.C.E. Inc.) was the structural engineering firm in charge of all structural designs for the hotel. Construction began in spring of 1978, and by the winter of the same year, Havens Steel Company was contracted to build the walkways. G.C.E. proposed a design which used a single rod from which all the walkways were to be hung (figure on the left). However, Havens implemented a design which used two rods (figure on the right) since this design was easier and cheaper to build. The top rod would attach to ceiling while the bottom rod would serve as the base for the next skywalk.3
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Proposed Design4 |
Actual Design5 |
A better understanding of why the skywalks collapsed is given by the following explanation: "Suppose a long rope is hanging from a tree, and two people are holding onto the rope, one at the top and one near the bottom. Under the conditions that each person can hold their own body weight and that the tree and rope can hold both people, the structure would be stable. However, if one person was to hold onto the rope, and the other person was hanging onto the legs of the first, then the first person's hands must hold both people's body weights, and thus the grip of the top person would be more likely to fail. The proposed design is similar to the 'two people hanging onto the rope' while the actual design is similar to the 'second person hanging from the first person's legs'. The first person's grip is comparable to the fourth level hanger rod connection. The failure of this 'grip' caused the walkway collapse."6
In the end, communication problems within G.C.E. and Haven led to the collapse of the walkways. If G.C.E had checked the final designs, they would have noticed that the rods could not hold the weight of the walkways, and the collapse could have been avoided. For more information visit:
http://www.eng.uab.edu/cee/REU_NSF99/hyatt.htm#Roddis