I-95 Bridge Collapse-30 years ago today.

[Mergingtraffic]

http://interactives.wtnh.com/photomojo/gallery/8011/156947/1983-mianus-river-bridge-collapse/

The Mianus River Bridge on I-95 NB in CT collapsed 30 years ago.

[Pete from Boston]

I can't believe it was thirty years ago.  A bad year on the Connecticut Turnpike, and one that begat a decade of changes on CT roads. 

[spmkam]

Wow I drove on the replacement on the anniversary

[BamaZeus]

My aunt had just been on the bridge literally 2-3 hours before the collapse, on the way back from the City.  I remember what a cluster---- it became re-routing traffic around the area.

I want to say they temporarily allowed some smaller trucks onto the Merritt, but they had to exit and use local streets because of the bridge restrictions.

[roadman65]

Yes I remember this one now that you mentioned it.  If memory recalls it was caused by a missing pin in the infrastructure.

Also to remember now other such disasters like the NY Thruway Bridge Collapse which will be almost 30 years coming up in a couple of years.  Then its over 33 years for the Sunshine Skyway disaster and since all of these you have had I-35W in Minneapolis and one on I-40 in Oklahoma, as well as the Texas 100 bridge to South Padre Island.

[roadman]

Yes I remember this one now that you mentioned it.  If memory recalls it was caused by a missing pin in the infrastructure.

A little more complicated than that.  Most of the drains had been paved over, which resulted in clogged expansion joints and resultant corrosion of the pins - this is what led to the "missing" pin, which actually fell off.  At the time, there was also some discussion that the loading forces on the span were improperly calculated to begin with (shades of 35W?)- the designer apparently calculated for a dead straight and mostly level span, whereas the bridge was on a curve and had some superelevation.

Unfortunately, the full NTSB report of the collapse investigation is not available on-line. However, the NTSB safety recommendation letter to the Governor of Connecticut - which includes the key findings of the investigation - can be found at http://www.ntsb.gov/doclib/recletters/1984/H84_31_39.pdf .  A good discussion of the Mianus River collapse can also be found in the book When Buildings Fall Down.

On a personal note, a friend of mine crossed the bridge approximately 15 minutes before it fell.