Sound Beach Avenue Bridge (No. 03954)
Sound Beach Avenue Bridge
Replacement of Sound Beach Avenue Bridge (Bridge No. 03954)
The existing Sound Beach Avenue Bridge was built in 1925 and rehabilitated in 1977 while adding an additional culvert to the south to relieve flooding. The current structure consists of 2 spans, a concrete deck span and concrete box culvert span, which create a center pier. The existing bridge is located adjacent to Binney Park in Old Greenwich and it has a deteriorated stone masonry fascia. It has rated poorly during the last series of inspections and recommended for immediate replacement. A most recent routine and underwater inspection concluded that the bridge had continued to deteriorate and the superstructure showed the most damage with exposed rebar, cracking, spalls, honeycombing and scale on the concrete slabs. If the deterioration continues and is rated at 3 (critical), a load rating restriction will have to be in place which will restrict a majority of truck traffic. The Average Daily Traffic (ADT) in 2017 was approximately 14,500 cars per day.
Upon notification of the bridge’s poor rating, the Town began to gather preliminary information and seek grant funding for the bridge design and replacement. The Town hired Weston and Sampson, Consultant Engineers and TranSystems, Traffic Engineers to complete a preliminary assessment of the bridge and surrounding area. A preliminary bridge design assessment requires that the existing roadway and adjacent intersections are reviewed to make sure that they meet the most recent Federal Highway Standards for Roadway Design. Also required is a review the accident history, emergency access, turning movements, compliance with the most recent Manual on Uniform Traffic Control Devices (MUTCD) standards and FEMA 100-year flood capacity requirements.
This assessment concluded that the current configuration at the intersection of Sound Beach Avenue/Laddins Rock Road/Harding Road is not compliant with the Federal Highway Standards (FHWA). Additional review of crash history data during the design process recommended improvements to the intersection of Sound Beach Avenue and Forest Avenue. Additionally, this area was flagged by the Town’s Flood and Erosion Control Board (FECB) and Emergency Services as an area prone to flooding. This area is listed as a high priority project under the FECB to mitigate flooding caused during high tide and extreme rain events. Emergency Services flagged this area because emergency vehicles are prohibited from passing through the intersection of concern during large storm events.
Three Public Meetings were held, between 2013 and 2018 to present the issues and recommendations noted above. A Municipal Improvement was denied by the Planning and Zoning Commission causing the Town to move forward with only the bridge replacement.
The State of Connecticut provided the Town with a commitment to fund through the Local Transportation Capital Improvement Program (LOTCIP) in the amount of $3.9 million dollars.
The existing bridge will be replaced by a single span precast concrete structure with masonry facing which will match the look of the existing bridge. The new design will eliminate the center pier which will increase the hydraulic efficiency of the bridge. The bridge can be constructed utilizing Accelerated Bridge 4 Construction (ABC) techniques. This could significantly reduce the road closure time to approximately 3 months. If the road were to remain open to alternating one lane traffic, it is anticipated the project could last 2‐3 years.
The proposed bridge will have an out to out width of 52’-6” to allow for construction of 1-10”’ wide parapets on each side (the bridge walls near the sidewalk), Two 5’-6“ wide sidewalks, Two 10’ travel lanes (one in each direction) and should widths which vary. The existing out to out width is 50’-7” with the attached sidewalk.
The proposed structure will have a masonry fascia to match the existing look and to flow with the park setting and surroundings. The elevation of the bridge will change.
The bridge serves three purposes – supporting traffic traveling on Sound Beach Avenue, allowing water to flow from Cider Mill Brook into Binney Pond and allowing pedestrians to safely travel to and from their destination. The bridge replacement will ensure that all of these functions can continue for years to come.
Funding for Construction is currently being requested through the Capital Budget Process for Fiscal Year 2020/2021.
The temporary traffic and pedestrian detour will be the most noticeable impact of this project. Both detours will be posted with signage and last approximately 3 months. For vehicles, it will utilize Harding Road and Forest Avenues. Local driveway access will be maintained throughout construction. For pedestrians, it will utilize the existing crosswalks in the vicinity and the existing sidewalks through Binney Park. It is anticipated that the total project duration will be approximately 1 year.
Existing utilities, such as sewer, drain, water and gas will be temporarily relocated prior to the removal of the existing structure.
Anticipated Project Timeline
Fall 2019/Winter 2020 – Semi-Final Design and Coordination with utilities for proposed relocations.
March 2020 – Final Design Submission from Town’s consultant
Spring 2020 – Submit Required Permits (IWWA, CTDEEP, ACOE)
May 2020 –Advertise Construction to Bid
July 2020 – Start Construction
Contact: Gabriella M. Circosta Cohee, P.E., Senior Civil Engineer
DPW – Engineering Division