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Safety Recommendation Details

Safety Recommendation H-84-032
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: ESTABLISH AND ENFORCE A POLICY OF REVIEWING AND EVALUATING PROPOSED MODIFICATIONS OF BRIDGE DRAINAGE SYSTEMS TO PRECLUDE REDUCING THE EFFECTIVENESS OF THE 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 is pleased to learn that the latest revision to the Bridge Design Manual requires newly designed or rehabilitated bridges to have a drainage system which will be as maintenance-free as possible and further requires that adequate cleanouts be specified to ensure ease of maintenance. This recommendation has been classified as "Closed--Acceptable Action." We would appreciate receiving a copy of the latest Bridge Design Manual which is mentioned in Mr. Burns' response.

From: State of Connecticut
To: NTSB
Date: 8/6/1987
Response: THE PRESENT REVISION TO THE BRIDGE DESIGN MANUAL REQUIRES THE DESIGNER OF NEW STRUCTURES OR REHABILITATED BRIDGES TO HAVE A DRAINAGE SYSTEM WHICH WILL BE AS MAINTENANCE-FREE AS POSSIBLE AND FURTHER REQUIRES THAT ADEQUATE CLEANOUTS BE SPECIFIED TO ENSURE EASE OF MAINTENANCE.

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