Mianus River Bridge
Overview
 
The Mianus River Bridge carries Interstate 95
Interstate 95 in Connecticut
Interstate 95, the main north–south Interstate Highway on the East Coast of the United States, runs in a general east–west compass direction for 111.57 miles in Connecticut from the Rhode Island state line to the New York State line. I-95 Southbound from East Lyme to the New York State...

 over the Mianus River
Mianus River
The Mianus River is a river in Westchester County, New York and Fairfield County, Connecticut, in the United States. It begins in the town of North Castle, New York in a series of ponds at about altitude...

 in the Cos Cob
Cos Cob, Connecticut
Cos Cob is a neighborhood and census-designated place in the town of Greenwich, Connecticut. It is located at 41.033 north, 73.6 west, on the Connecticut shoreline in southern Fairfield County. It had a population of 6,770 at the 2010 census....

 section of Greenwich, Connecticut
Greenwich, Connecticut
Greenwich is a town in Fairfield County, Connecticut, United States. As of the 2010 census, the town had a total population of 61,171. It is home to many hedge funds and other financial service companies. Greenwich is the southernmost and westernmost municipality in Connecticut and is 38+ minutes ...

. The bridge suffered a 1983 collapse, killing several motorists. The replacement span is officially named the Michael L. Morano Bridge, after a state senator who represented Greenwich.
The bridge had a 100-foot (30.5 m) section of its deck of its northbound span
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge.A span can be closed by a solid beam or of a rope...

 collapse on June 28, 1983. Three people were killed when their vehicles fell with the bridge into the Mianus River 70 feet (21.3 m) below, and three were seriously injured.

Casualties from the collapse were few because the disaster occurred at 1:30 a.m., when traffic was low on the often crowded highway.
The collapse was caused by the failure of two pin and hanger assemblies
Pin and hanger assembly
A Pin and Hanger assembly is used to connect two plate girders of bridges. These assemblies are used when the space between two bridge piers is too wide to be spanned by a single set of girders. To overcome this, steel beams are set with one end resting on a bridge pier, while the other end is...

 that held the deck in place on the outer side of the bridge.
 
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