East Rock Road Bridge over the Mill River
Rehabilitation of Bridge #04418
City of New Haven, Connecticut
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  • FAQ

    How is a bridge project funded?

    Within the State of Connecticut, bridges are either owned by a municipality or by the state, with a few minor exceptions.  The owner of the bridge is responsible for all maintenance, including rehabilitation and replacement.  Bridges owned by municipalities can be funded solely by the municipality or in conjunction with the State or Federal Bridge program.  Under the State Local Bridge Program municipalities receive a maximum of 33% of a bridge’s estimated construction cost. Under the Federal Local Bridge Program municipalities receive 80% of the estimated construction cost.  The balance of the cost comes from municipal funds.

    Why does it take so long to design and construct a bridge?

    The process to design a bridge takes time and involves the review of many of stakeholders.  Stakeholders include Municipal representatives, such as Public Works, Engineering, Economic Development, Parks and Recreation, Historical Society, and Local Wetlands/Inlands; and State and Federal representatives, such as ConnDOT, CTDEP, USCG, USACE, and National Register of Historic Places.

    Dependent upon the bridge, the process may not include all the noted steps. 

     Design Process 517x431

    Why detour vs staging construction?

    The detouring of traffic for the rehabilitation or replacement construction of a bridge results in minimized construction duration and cost and for safer construction.  Detouring is not always possible due to the lack of a route and the disinterest of the community being affected. In some bridge rehabilitation projects detour simply is not possible because of the type of existing construction to work with. 

    Although allowing thru traffic staging of construction typically takes longer therefore increasing the construction cost.  As noted, there isn’t always an option.

    What are hydraulics and hydrologics?  

    Hydrology is the science used to determine the amount of water that will flow towards a particular bridge during/after a storm event. Hydraulics is the science used to determine water surface elevations that will result when a particular volume of water flows through a river channel and/or floodplain.

    Why can’t a bridge just be made wide enough to meet our needs?

    Care must be taken to ensure that any widening of the bridge does not worsen flooding conditions downstream of the bridge. When the size of a bridge opening is increased, water that used to back up behind that bridge is allowed to pass through it. While this may decrease water surface elevations upstream of a bridge, downstream elevations are increased. This effectively moves a flooding problem without solving it. Care must be taken to ensure that any upstream relief from flooding does not hurt property lying downstream of a bridge. This is not only good design practice, but is also required by State and Local law.

    Why does the process take so long?

    Time is required to perform the hydrologic and hydraulic computations necessary to ensure that the delicate balance described above is achieved in accordance with State and Local regulations. Once the design is complete and submitted to State and Local authorities, additional time is required for a review of each design to ensure that the design conforms to applicable laws and regulations.

    What is scour?

    Scour is the most common cause of bridge failure in the U.S., and is defined as the erosion of stream bed material around and/or beneath a bridge substructure element (abutment, column, or pier) caused by the flow of water around or adjacent to the bridge. Excessive scour can undermine a substructure element and lead to a partial or total bridge collapse.

    What is the current Average Daily Traffic (ADT) for the East Rock Road Bridge?

    The ADT for the bridge is considered low – (1700 ADT, Year 2007). 

    What was the original bridge design?

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