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

    Bridge No. 04418 carries East Rock Road over the Mill River in New Haven, Connecticut. It is located approximately 90 feet west from the intersection of East Rock Road and Farnum Drive and it is classified to be a “Rural Minor Collector”.

    The 84 foot long single span steel deck arch bridge carries one lane of vehicular traffic in the eastbound and westbound directions over a roadway with a 20 foot curb-curb width and two pedestrian sidewalks 5 foot wide. The bridge superstructure consists of steel grid deck with in-fill concrete supported on steel floorbeams, columns and deck arches. The arches are part of the original 1900 bridge construction while the remainder of the superstructure was replaced during the 1984 rehabilitation.

    Based on the original construction plans, the abutments and the wingwalls appear to be gravity type walls with brown cut stone masonry facing. The substructures are supported by timber pile foundations, design details of which are not available in the original construction plans. The abutments and wingwalls were modified during the 1984 rehabilitation with the addition of a concrete stem to support the new bridge superstructure. The bridge is located on a tangent horizontal alignment and a slight crest vertical curve.

    The bridge deck was observed to be in “Serious” condition and the overall condition of the bridge was rated to be “Poor” according to a routine inspection performed by Connecticut Department of Transportation (ConnDOT) in August 2007. The superstructure was observed to be in “Satisfactory” condition with the structural steel and arch bearings exhibiting random areas with rust and pitting type section losses. The previous inspection noted the substructures to be in “Satisfactory” condition with the abutments and wingwalls exhibiting cracked, deteriorated and missing mortared joints at several random locations. No evidence of shifting stones indicating possible overstress has been observed in any of the previous inspections.

    The channel flow is tidal at the bridge. According to information available from ConnDOT Inspections, the condition of channel and channel protection is “Good”, the available hydraulic opening will result in a slight chance of overtopping bridge deck and roadway approaches (NBIS Item 71 rating 7) and the scour critical rating indicates that an evaluation has not been made (NBIS Item 113 rating 6).

    The condition of the approach roadway was noted to be “Poor” with the guiderails not meeting current safety standards. The bridge currently has an inventory load rating capacity of 14 Tons for an AASHTO HS20 vehicle (36 Tons standard) and is posted for 17 Tons and 24 Tons for a single unit truck and a semi-trailer truck, respectively.

    An assignment meeting was held on April 8, 2009 between Dewberry, Close Jensen & Miller (CLE), the City and ConnDOT to discuss the framework of the proposed scope. A subsequent scope discussion meeting was held between Dewberry, the City and CLE on August 4, 2009.

    Dewberry-Goodkind Inc. supported by sub-consultants, Martinez- Couch and Associates (Surveyors & DBE), William Kenny and Associates (Soil Scientists) and Archaeological & Historical Services (Archaeological Consultants & DBE) will prepare a Preliminary Engineering Study Report summarizing the evaluation of feasible design alternatives and make recommendations to the City for the selection of the best alternative. Subsequent to the approval of the Preliminary Engineering Study, contract documents including Plans and Specifications will be prepared in accordance with the negotiated scope.

    All work will be performed in accordance with the applicable FHWA, AASHTO and ConnDOT guidelines and specifications and prepared in English units. AASHTO Standard Specifications (HS-20 Design Vehicle) will be utilized since the current project is a “bridge rehabilitation” project and unlike a “bridge replacement” project, a majority of bridge elements built either during the 1900 or the 1984 construction and designed using the AASHTO Standard Specifications are anticipated to be strengthened and reused in the proposed design.