Route I-78 Connector

Due to the condition of the I-78 Interchange bridge superstructures along with its substandard roadway safety features and clearances, the New Jersey Department of Transportation (NJDOT) initiated a project to raise and widen the existing I-78 Connector northbound roadway over U.S. Route 1 & 9, Route I-78 and Route I-78 ramps in Newark, New Jersey.  Since the project was located next to Newark Liberty International Airport, close coordination with the Port Authority of NY & NJ would be required.  Arora and Associates, P.C. was selected by the NJDOT as the prime consultant to advance this project on an accelerated schedule.  Arora’s proposed interchange reconstruction design addressed the substandard roadway conditions and provided three lanes for westbound traffic and two lanes for eastbound traffic along Route I-78.  To achieve this lane configuration, the existing ramps and structures providing access to and from the I-78 Connector were widened and new sign support structures were added.  The design provided a comprehensive solution for the functionally obsolete interchange and included the rehabilitation and/or superstructure replacement for the following structures:

• Route I-78 Connector over Ramps B & C (Structure No. 0725-154)
• Route I-78 Connector Ramps A & B over Route 1 & 9 (Structure No. 0725-155)
• Route I-78 Connector Ramps C, QP & D over Route 1 & 9 (Structure No. 0725-170)
• Route I-78 Connector Ramps B & C over Route I-78 (Structure No. 0725-156)
• Route I-78 Connector Ramps QP & R over Route I-78 (Structure No. 0725-157)
• Eight (8) Retaining Walls
• Seven (7) new Overhead Sign Support Structures
• Three (3) new Cantilever Sign Support Structures

The design also raised the roadway profiles to increase the minimum vertical underclearances to 16'-9" over Route I-78 and the Route I-78 Ramps and to 15'-7" over U.S. Route 1 & 9.  Maintenance and protection of traffic was a major consideration during the development of the project.  All of the bridge and ramp construction had to be performed using staged construction to maintain the existing high volumes of traffic.  The structural framing plans were designed to accommodate the staging and facilitate future deck replacements.  The existing abutments and piers were widened to accommodate new superstructures and the pier for Structure No. 0725-157 was replaced.  To improve the seismic performance of the structures, all of the existing steel rocker bearings were replaced with either elastomeric or pot type bearings.

The project also presented geotechnical engineering challenges.  It was necessary to evaluate the existing abutments for increased earth pressure, new superstructure loading, HS-25 live load, and Seismic Performance Category B requirements.  Arora’s geotechnical evaluation indicated that the project required both shallow and deep foundation schemes depending upon the location within this highly variable project site.  To mitigate the increased abutment loading, lightweight concrete was used in the bridge decks, abutment seat extensions and backwalls, and lightweight fill was specified behind the abutment walls.  A surcharge program was also employed in the embankment construction to mitigate settlement.