The Mianus River Bridge Collapse

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My sister-in-law used to live in a condo in Norwalk. On the night of June 28, 1983 she invited us to drive up to her condo from Pemberwick to use the pool. My oldest daughter was only about 6-months old. So we packed up the car around 7:30pm and drove down I-95 (over the Mianus bridge) to Norwalk.  After a refreshing swim, we drove back over the bridge around 9:30 pm. The next morning, my wife, Linda, told me that the Mianus River Bridge had collapsed at about 1 o'clock in the morning, and there was a report on the news. I was stunned!

 

Tri-State Transportation Campaign

The bridge was built around 1958 as part of the Interstate highway system.  The highway (I-95) stretched all the way from Maine to Florida. Eisenhower had built the system of highways to move troops in the event of an national emergency. The span was composed of 4 spans, each 100 feet long, weighing 500 tons. There were 6 lanes - 3 north bound and 3 south bound. A "pin and hanger" system was utilized. Spans were connected by hangers that were shaped similar to bicycle chain links. It was a novel design feature. Furthermore, it was cheaper than using other designs.

About 10 years before the collapse, road crews paved over storm drains on the bridge. This meant that rain could not run off the bridge, but rather collected in unlikely spots in the structure. Unfortunately, one of these spots was between the pinhead and associated hanger, resulting in rust buildup.  Evetually, two of the pins broke, and left two other pins to uphold the 500 ton weight. This additional weight was too much for remaining pins the 100 foot span fell 70 feet to the river below.

 The gaping hole in the highway "swallowed up" two tractor trailers and two passenger cars. One tractor trailer landed with its cab in the mud and it's trailer leaning end to end against a pylon. One couple - who nearly escaped with their lives - tried to flag down on-coming traffic. Unfortunatley, one BMW ignored attempts to flag it down and went over the edge. The car was totally submerged in water. Two passengers died. Several people were pulled out of the water by local boatmen. A man driving a tractor full of meat died. The meat had to be pulled out and rewrapped. A young girl in a Toyota landed on a tractor leaning against the bridge and slid down. Three people were killed and three were seriously injured. It could have been much worse if the accident had happened during the day, especially during the rush hour.

Officials had to detour traffic around the fallen bridge. A special off ramp was built near the Bush-Holley House. Traffic got off at this temporary exit, drove down Strickland Road to River Road, then turned on to the Post Road East to Exit 5. Needless to say, this increased traffic in the residential area tremendously. Residents complained and even formed a group to protest. A 15 minute trip from the New York state border to Stamford now took 60 minutes. Fortunately, officials were able to re-open the south bound lanes within a few days and by July 22 a temporary span was in place for the north bound lanes.

The NSTB (National Safety and Transportation Board) performed an investigation of the accident. It concluded that a rusted pin had caused the accident and that the design of the bridge was inadequate. There was nothing underneath to support the spans. Furthermore, there was an insuffient number of inspectors (12) in the state to inspect the many bridges (about 3,600 highway and 1,200 local) used daily. It was also determined that the inspection process wasn't thorough enough. There was no requirement (or equipment) to check major stress points on the bridge. To make matters worse, some inspectors signed off without even performing an inspection.

The tragedy set off a bridge inspection and replacement program not only in Connecticut, but across the country. New pylons (cement supports) were built underneath the entire span of the bridge. Structural steel was replaced and the lanes on the span were increased. More inspectors were hired and new inspection procedures were put in place. In Boston it was discovered that the Harvard Bridge had the same design.

 

During the decades since the collapse, there has been a lot of talk about the national infrastructure needing attention. Some groups believe there are serious problems with our highways and bridges.  It is estimated by The Tri-State Transportation Group that 2/3 of money for highways in Connecticut has been spent on expansion instead of maintenance. It cost $20 million between 1983 and 1992 to repair the Mianus River Bridge. Preventive maintenance could go a long way to prevent a more costly (in today's dollars) accident.

 

SOURCE:   "The Mianus River Bridge Colapse"; OHP, 1988 

6 Comments

thank you for the information.
can I take some for my research?

Yes, as long as you cite Greenwich Library and the Oral History Project.

There were also some useful Greenwich Time articles, which we have on microfilm, that might help you. Carl

Thank you for your helpful information about the collapse of the Mianus River Bridge. It will be part of my in class PowerPoint presentation about the collapse of the Mianus River Bridge, so if you have related video to give it will be great.

Mohamed

I'm glad you can use the blog for your class. Unfortunately, I don't know of any video, but I'm sure the Connecticut State Library or History Channel will eventually release one!

Hi, I'm doing a report on this bridge collapse. I am really struggling to find the contractors and designers involved with the construction of this bridge. I don't suppose you could help me with this? Thanks a lot!!

J - According to a report to the NSTB in 1983, the bridge was designed by a predecessor to the TAMS Co. in New York City. It was previously the Knappen-Tippetts-Abbett-McCarthy Co. It designed the bridge in 1954 and 1955.

I think the Connecticut State DOT (Dept. of Transportation) and a private company were involved in the construction. I need to look further.

I hope this helps. Carl :) PS Look at this link!

http://cslib.cdmhost.com/cdm/singleitem/collection/p4005coll11/id/35/rec/3

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This page contains a single entry by Carl White published on March 24, 2011 11:29 AM.

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