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Safety Recommendation Details

Safety Recommendation H-84-031
Details
Synopsis: ON JUNE 28, 1983, A 100-FOOT-LONG SUSPENDED SPAN BETWEEN PIERS 20 AND 21 OF THE EASTBOUND TRAFFIC LANES OF THE INTERSTATE ROUTE 95 HIGHWAY BRIDGE OVER THE MIANUS RIVER IN GREENWICH, CONNECTICUT, COLLAPSED AND FELL 70 FEET INTO THE RIVER BELOW. TWO TRACTOR-SEMITRAILERS AND TWO AUTOMOBILES PLUNGED INTO THE VOID IN THE BRIDGE AND WERE DESTROYED BY IMPACT FROM THE FALL. THREE VEHICLE OCCUPANTS DIED, AND THE OTHER THREE RECEIVED SERIOUS INJURIES. THE NATIONAL TRANSPORTATION SAFETY BOARD DETERMINED THAT THE PROBABLE CAUSE OF THE COLLAPSE OF THE MIANUS RIVER BRIDGE SPAN WAS THE UNDETECTED LATERAL DISPLACEMENT OF THE HANGERS OF THE PIN AND HANGER SUSPENSION ASSEMBLY IN THE SOUTHEAST CORNER OF THE SPAN BY CORROSION-INDUCED FORCES DUE TO DEFICIENCIES IN THE STATE OF CONNECTICUT'S BRIDGE SAFETY INSPECTION AND BRIDGE MAINTENANCE PROGRAM.
Recommendation: THE NTSB RECOMMENDS THAT THE CONNECTICUT DEPARTMENT OF TRANSPORTATION: REOPEN THE PAVED-OVER DRAINS ON THE MIANUS RIVER BRIDGE AND ANY OTHER BRIDGE IN CONNECTICUT WHICH MAY HAVE PAVED-OVER DRAINS, INSTITUTE A PROGRAM TO MODIFY THE BRIDGE DRAINAGE SYSTEMS SO THAT THEY PROVIDE FOR PROPER RUNOFF OF SURFACE WATER AND TO REQUIRE REGULAR CLEANING AND MAINTENANCE OF DRAINAGE SYSTEMS.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Highway
Location: Mianus River, Greenwich, CT, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA83AH003
Accident Reports: Collapse of a Suspended Span of Inter- state Route 95 Highway Bridge over the Mianus River
Report #: HAR-84-03
Accident Date: 6/28/1983
Issue Date: 7/19/1984
Date Closed: 10/26/1987
Addressee(s) and Addressee Status: State of Connecticut (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: State of Connecticut
Date: 10/26/1987
Response: The Safety Board understands that the paved-over drains on the Mianus River Bridge and other bridges in Connecticut have been reopened and that a program to regularly clean and maintain bridge drainage systems has been initiated. Based on this information, Safety Recommendation H-84-31 has been classified as "Closed--Acceptable Action."

From: State of Connecticut
To: NTSB
Date: 8/6/1987
Response: THE PAVED-OVER DRAINS ON THE MIANUS RIVER BRIDGE AND ON OTHER BRIDGES IN CONNECTICUT HAVE BEEN REOPENED. A PROGRAM TO REGULARLY CLEAN AND MAINTAIN BRIDGE DRAINAGE SYSTEMS HAS BEEN INITIATED.

From: NTSB
To: State of Connecticut
Date: 5/15/1987
Response: