The Interstate 78 (I-78) Bridge Under Clearance Project in Berks County, Pennsylvania, required the delivery of six bridges in sequential order. In PennDOT’s public outreach efforts, there was immense community support for the bridges to be constructed under brief roadway closures with accelerated bridge construction (ABC) techniques, rather than longer-duration, traditional construction methods.
The I-78 Bridge project is a prime example of how ABC delivers tremendous benefits for owners and the community. It is a powerful tool for rapidly upgrading bridge infrastructure. When supported by high-performance precast concrete solutions, the results are remarkable. In its completion, the I-78 Bridge won a 2020 PCI Transportation Special Solution Design Award thanks to precast’s inherent versatility and a skilled project team:
- Owner: Pennsylvania Department of Transportation Engineering District 5
- PCI-Certified Precast Producer: PennStress, a division of MacInnis Group
- Engineers of Record: Alfred Benesch & Company; Erdman Anthony; AECOM; Johnson, Mirmiran & Thompson
- Contractor: HRI Inc.
We’ll explore the versatility of precast concrete, so you can better determine if it’s right for your next project. To learn more about total precast solutions for bridge infrastructure, watch the video below.
A Full Precast Solution
PennDOT Engineering District 5 chose the ABC technique to build six precast concrete structures composed of single-span prestressed concrete bulb-tee bridge beams along with precast concrete substructures accented by a stained, stone-faced formliner. As the first Pennsylvania ABC project to incorporate tall, cantilevered abutments, the I-78 Bridge project used more than 450 prefabricated concrete elements.
Although complex in design and fabrication, precast proved to be the best-choice building material. The six structures had significantly different bridge widths; some used precast concrete deck panel components that extended across the full-bridge width while others used two or three precast concrete deck panel components, and precast allowed for complete customization. The full-depth precast concrete deck panel pieces were typically eight inches thick and less than fourteen feet wide to facilitate transportation to the project site.
Design Accuracy & Aesthetic Versatility
The precast concrete detailing for all six structures was completed by PennStress, which used TEKLA 3D modeling software so that no two pieces were the same structural layout or appearance. TEKLA virtually eliminated production material conflicts, enhanced the accuracy of the splice sleeve layouts, and even allowed for a visual representation of the stone-faced formliner layout between pieces to provide the desired look.
To customize the look and feel of each bridge, the precast producer used a random block stone architectural finish on the outside face of the barriers and the front of the abutment and wing wall stems. Five different-colored stains were also applied, providing a natural stone appearance and a simple, consistent, and visually appealing aesthetic.
Minimized Community Disruption
Each bridge was individually detoured for a specific duration to allow demolition and reconstruction to take place. Much of the work also took place at night, minimizing daytime traffic disturbance. Segments of the work included short-term, scheduled interruptions to the traffic flow on I-78, a major interstate in the Mid-Atlantic region.
This plan reduced the average construction duration for each structure from one year to just forty-five days. All six bridges were completed in two construction seasons, minimizing the project’s social and economic impact on local businesses.
Learn More About Precast, Prestressed Concrete
Learn why precast was chosen for the Interstate 78 Bridge in the video above and share it with your industry peers and clients to showcase the reliability and versatility of a total precast solution for your next project.
Interested in learning more about precast and how the precasters of the PCI Mid-Atlantic Chapter support projects of all kinds? Explore the PCI Mid-Atlantic Solutions Center for helpful resources and get in touch with PCI-MA for precast information, higher education partnerships, and more.
More Resources on Precast Bridge Design
PCI pre-recorded webinar Accelerated Bridge Construction Using Precast Concrete
