In this day and age of technology it would be almost impossible to think that a bridge could fail. But, there is a long list of failed bridges and students, if they are to successfully design a bridge, need to know how a bridge can fail. I would like to contrast two bridge failures. Also, sample websites depicting video bridge failures are suggested in activity 3.
In July 1997 the Maccabiah Bridge collapsed and killed two athletes and injured 60 others. It was a wooden pedestrian bridge constructed for the Maccabiah Games in Tel Aviv, Israel. The Games celebrate the Zionist Revolution and is also a way for the Jewish people to demonstrate their unity and athleticism. The Maccabiah Bridge spanned 60 feet long and 18 feet wide over the Yarkon River. It was built as a temporary bridge where the athletes would wait before the opening ceremonies of the games in Ramat Gan Stadium. The bridge buckled before the ceremony could begin.
An investigation ensued and the public commission deemed that the bridge failed because of poor planning and construction and found fault at all levels in the process. It was found that the engineer never submitted a plan and failed in adequately identifying the bridges intended use. It was also recognized that the engineer did not supervise the construction.
The construction company never communicated with the engineer, it used substandard materials, and the company was not authorized to build this type of structure.
Interestingly, the organization committee of the games did not communicate with the principals of the project and did not appropriately manage the athletes on the bridge.
In contrast, the Mianus River Bridge in Cos Cob, Connecticut collapsed in 1983 because of metal corrosion and fatigue.
The bridge was constructed in 1958 as part of Interstate 95 traveling southward from New York through Connecticut and northward through Massachusetts. It consisted of six lanes-three lanes that went northbound and three lanes that went southbound. The bridge was composed of four spans each weighing 500 tons. A new design called the pin and hanger was employed to connect the spans. The outline of the hanger is oval. At the top and bottom of the oval piece are two holes for metal pins, similar to rods, to go through and then kept in place with retaining bolts, keeper plates, and knots.
Ten years prior to the disaster, the bridge was resurfaced and the storm drains on the bridge were paved over. This action allowed water, stilt, and dirt to reach the hangers. Road treatment in winter which contains a fair amount of salt, the nearby salt marsh in conjunction with the tidal flow from Long Island Sound adding more salt, and harsh winters all led to the pin and hanger's corrosion. The National Safety and Transportation Board conducted an investigation. Deputy Commissioner CT DOT Carl F. Bard P.E. stated that location, heavy traffic, and environmental factors were the cause of the fatigue and rusting of the pin and hanger that caused one pin to fall off and caused the second pin and hanger to let go since it could not support the weight of the bridge alone. A one hundred foot section of the bridge collapsed and fell into the river.
It was determined that the bridge was not routinely inspected, and, that all Connecticut bridges using this system were inadequate. The disaster of the collapse of the Mianus River Bridge that sent two cars and two tractor trailers into the river killing three people could have been avoidable.