"The Alexander Road project [has] improved motorist and pedestrian safety and decreased congestion by replacing the existing, outmoded bridge and intersection with a more efficient modern roundabout and a new steel bridge complemented by sidewalks and shoulders. The improvements will benefit those traveling to and from nearby Princeton Junction Train Station"
-Former NJDOT Commissioner Kolluri
The original Alexander Road bridge was a deteriorated, 146 ft.-long, three-span structure built in 1941, that traversed four Amtrak Northeast Corridor (NEC) electrified tracks. The 20-foot bridge roadway width did not meet minimum design standards due to its poor vertical sight distances on both approaches, substandard lane widths on the bridge deck, and substandard horizontal and vertical railroad clearances.
The project was further complicated by a dangerous stop-controlled “T” intersection at Alexander Road and North Post Road. NJDOT sought to construct a new bridge on an adjacent alignment, improve traffic circulation and safety, minimize traffic disruptions during construction, minimize right-of-way impacts, and provide an aesthetically pleasing solution consistent with its Smart Solutions doctrine.
Urban provided fair compromise between replacing a structurally deficient and functionally obsolete bridge with preserving and respecting the context of West Windsor’s community setting. The project achieved consensus through collaboration. Agency and community relations activities were integrated into every phase of the project and contributed to its success. This was accomplished by delivering a consistent message throughout the project, facilitating creative solutions with partners, and providing design details and solutions that incorporate the community context.
We were responsible for preliminary and final design of the bridge's aesthetic, functional, and safety improvements, including improved substandard horizontal and vertical geometry along Alexander and North Post Roads (two municipal roadways), adding shoulders on all bridge approaches, providing a suitable cross-section and sidewalk for bicycle and pedestrian compatibility, and developing an AASHTO-compliant modern roundabout, joining the existing non-signalized intersection of Alexander and North Post Roads.
From our discussions with the community, maintaining the look and feel of other structures within the surrounding areas was important. Therefore, the project employed Smart Growth practices and used appropriate Context-Sensitive Design (CSD) elements to make the project blend with the community, motorists, and pedestrians. Pedestrian accommodations were also key to allow area residents easy access to the Princeton Junction Train Station, which is in close proximity to the Alexander Road Bridge.
A significant number of difficult issues presenting themselves had to be overcome during the project. For example, all work adjacent to the Northeast Corridor required approval of detailed Site Specific Work Plans (SSWPs) for track outages. SSWPs were developed for construction of the new bridge, removal of the existing bridge, construction of the new catenary structure, and re-profiling of the transmission lines (including extensions to existing transmission poles).
Required demolition and new construction had to occur without interfering with electrified transmission lines above the bridges or electrified catenary lines below them. Amtrak electric traction work for the railways below the bridge made it so that completion of the project was required within a very limited window of time.
Additionally, because of the work traffic in the West Windsor Parking Authority Parking Lot, construction could only be performed during the summer months in 2006.
Finally, requirements relating to various utilities presented more constraints, including:
Additional innovative approaches included:
Utility coordination, in accordance with the NJ State Utility Accommodation Policy, included aerial electric, telephone, and cable TV; and underground gas, water, sewer, and four fiber optic communication facilities within Amtrak right-of-way. The electrification facilities at the Alexander Bridge location (12 wires above, seven wires below, and four systems attached to the bridge) required re-profiling and re-support of the existing catenary system.
This project utilized InRoads 8.1 and Microstation 7.1 design software and was designed in accordance with the NJDOT Design Manual, Roadway; AASHTO LRFD Bridge Design Specifications; and AASHTO Roadway Design Standards. This project followed NJDOT’s Pipeline II Project Delivery Process and used the NJDOT Procedures Manual, CADD Standards Manual, and current applicable BDCs.
The final product incorporated innovative design and construction methodologies rich in Context Sensitive design, including integrated solutions that properly meshed with the West Windsor Master Plan.
Urban managed the project in a skillful manner, exceeding NJDOT’s expectations, resulting in a project that was delivered ahead of schedule, within budget and fully supported by the community. Improvements were achieved without disruption to NEC service and without interfering with electrified transmission lines above the bridges or electrified catenary lines below them. The ability to accurately estimate costs and schedule construction with consideration of prevailing market conditions and project constraints was an essential component in the success of this project.