Scope
Project Area & Site Context:
The project area is located on Belt Parkway immediately southwest of Sunrise Highway, approximately three miles east of the Van Wyck Expressway and roughly 3,200 feet west of the City line. The project area’s eastern extent is the Sunrise Highway overpass. The project area then runs approximately 470 feet west along the Belt Parkway median to the end of the displaced barriers, which marks the western extent of the project limits.
The eastbound Belt Parkway carries three lanes of traffic at this location, ultimately passing under bridges carrying the Sunrise Highway (i.e., the eastern project extent), the Long Island Rail Road Atlantic Branch, and North Conduit Avenue. In the westbound direction, the parkway carries four lanes of traffic that temporarily split into two divided thoroughfares as a result of these bridges' piers. This pair of two-lane westbound thoroughfares converges on the north side of the project area, and continue as a four-lane expressway.
Throughout the project limits, the Belt Parkway’s eastbound traffic is carried at a higher elevation than the westbound traffic. As a result of this grade separation between the east- and westbound
roadways, the existing barrier system was constructed as back-to-back half section barriers (as seen in the image to the right), but without either continuity plates or backup posts. Over time this back-to-back half section barrier system has become displaced, creating a hazard for parkway traffic moving in both directions.
2018 HDR Study – Existing Conditions & Recommendations:
In 2018, DOT contracted with Henningson, Durham and Richardson, Engineers & Architects (HDR) to investigate three city-owned expressway barriers known to be substandard condition – including the Belt Parkway barrier at Sunrise Highway – and to prepare a feasibility study for future capital improvements.
HDR’s geotechnical investigation of the Belt Parkway site determined that the barrier’s horizontal displacement is not likely the result of ground settlement, as previously hypothesized. The consultant identified several possible alternative causes of this displacement, among them: routine vehicle strikes (as evidenced by the numerous paint streaks observed on the existing jersey barriers), ground-borne vibration, the project area’s gentle sloping grade, and the median barrier lacking an anchor to the pavement.
As a solution, HDR has recommended construction of new concrete median barriers with L-shaped deep foundations to prevent future displacement. The consultant’s recommended alternative will maintain structural support of the new barrier, stay stable after vehicular strikes, and eliminate the localized tilting observed in the current half section barrier system.
The full 2018 HDR report is included in this document’s Appendix, Attachment 6.
Project Scope:
Install New Concrete Median Barrier with Deep Foundation
Consistent with HDR’s recommended alternative, this project will remove the existing half section barrier system on Belt Parkway and construct a single, reinforced cast-in-place barrier system with an L-shaped deep foundation running the 470-foot length of the project area. The deep foundation median barrier will have a similar section to the NYSDOT Standard Sheet 606-14, Concrete Median Barrier, but will need to be designed to a heights appropriate for the grade separation between the east- and westbound Belt Parkway roadways (as reflected in HDR’s Conceptual Design, Attachment 4).
As this state of good repair project is focused solely on the deteriorated condition of the half-section barrier system, the project scope does not include any curbline changes, roadway reconstruction (beyond that required to construct the new barrier), or resurfacing of the adjacent parkway.
HDR provided a preliminary cost estimate for the barrier replacement as a part of their 2018 deliverable, which serves as the basis for the cost estimate included in this document (Attachment 5).
Light Poles:
The project area contains three light poles sited within the existing barrier system, the foundations for which will need to be integrated into the redesigned barrier to maintain appropriate lighting conditions along this segment of the Belt Parkway. HDR has prepared a conceptual design for these light fixture foundations, which is also included in this document’s Conceptual Design section, Attachment 4. All impacts to the existing lighting system will require coordination with DOT Street Lighting, as discussed in greater detail within the Other Comments/Issues section of this document (see page 5).
Barrier Transition:
At the western extent of the project area, approximately 470 feet southwest of the Sunrise Highway overpass, the east- and westbound expressways reach approximately the same grade and the half-section barrier system transitions to a standard jersey barrier system. DOT anticipates that the new transition piece will also need to be constructed
