Bridge Replacement and Interchange Improvement

As a major engineering subconsultant on an Interstate 78 under-clearance improvement effort involving multiple bridges in Pennsylvania, Erdman Anthony provided complete bridge and highway engineering services for the replacement of Midway Road Bridge over I-78 using accelerated bridge construction (ABC) techniques.

The existing three-span prestressed box-beam bridge had a 13’ 8” under-clearance. It was replaced with a single-span prestressed PA bulb-tee beam superstructure supported on concrete abutments that provides a 16’ 6” under-clearance. The project also included reconstruction of 600 feet of approach roadway on each side of the bridge, reprofiling of the interchange ramps, and interchange-lighting modifications. 

Conventional construction methodology would have used half-width staged construction to reconstruct the bridge, requiring two construction seasons to complete the work. Vehicles on the bridge would have been limited to a single lane, with temporary signals used to allow for bidirectional traffic. Traffic would have had to endure this inconvenience for nearly two years. 

Instead, an ABC approach was implemented to minimize disruption to traffic during construction. The use of precast concrete abutments and footings, prestressed concrete beams, and precast deck panels with Ultra-High-Performance Concrete closure pours enabled enabled construction of the replacement bridge within a 60-day schedule, with all lanes of I-78 traffic under the bridge left open to traffic. 

A substantial public outreach program was implemented during the design phase to resolve concerns local business owners and residents had about the temporary closure. Ultimately, construction was completed on time and the project was well received by the community.