Overview
Mercer County Bridge #233.15 (NJDOT Structure #11B3315) carrying Eglantine Avenue over Lewis Brook within the Borough of Pennington is a 10 ft concrete-encased steel stringer culvert constructed by Mercer County in 1908, was originally 67.8 ft long and subsequently widened in 1940 and circa 1960, extending nearly 227 ft through reinforced-concrete box culvert extensions beneath adjacent private properties toward the southwest, or upstream, end of the structure. Bridge #233.15 crosses the Lewis Brook connector, which includes two 36-inch diameter reinforced concrete pipes at the upstream end on the west fascia of the bridge. Eglantine Avenue has an estimated Average Daily Traffic (ADT) of 2,005 vehicles in the project area, a posted speed limit of 25 mph, and a public right-of-way width of 60 ft. The surrounding area at the T-intersection of Eglantine Avenue, East Franklin Avenue, and Lewis Brook Road is primarily residential development. Underground and aerial utilities are present in the vicinity of the structure. An inlet is located on top of existing structure. The project is being undertaken by the County of Mercer to replace existing structurally deficient structure with proposed structure meeting current NJDOT and AASHTO design standards.
About the Project
LiRo-Hill is delivering comprehensive engineering services—including conceptual, preliminary, and final design—for the replacement of the existing bridge structure along with associated roadway improvements within the public right-of-way, maintaining the existing roadway alignment with minimal impact to existing utilities, traffic and any environmentally sensitive areas. LiRo-Hill, in partnership with subconsultants, will deliver geotechnical and environmental services. All requisite permits from NJDEP, HPO, the Delaware & Raritan Canal Commission, and the Soil Conservation District (SCD) will be obtained prior to construction. The design of the roadway, MPT, drainage, and structures will adhere to current AASHTO and NJDOT standards. Plans, specifications, and estimate (PS&E) documents are being prepared in accordance with both County and NJDOT requirements, and the final construction documents will undergo NJDOT Local Aid review.
Project Challenges & Solutions
The structure location at the intersection presents specific challenges related to maintenance and protection of traffic during construction. The aerial and underground utilities crossing the structure will have to be accommodated during construction and in the final conditions requiring close coordination with utility owners to develop the accommodation plan.
