Ultra-High Performance Concrete
Ultra-High Performance Concrete (UHPC) is a steel fiber-reinforced, cement-based composite material used to create stronger and longer-lasting connections between prefabricated bridge elements (PBE). PBEs are structural components of a bridge that are built offsite then moved, ready to erect, to the project location. The durability of prefabricated bridge spans, and how quickly they can be constructed, relies on the connections between the elements. UHPC for PBEs is a Federal Highway Administration (FHWA) Every Day Counts Round 3 (EDC-3) innovation that Pennsylvania championed.
Pennsylvania, an early adopter of UHPC, has not only developed standards for using UHPC PBE connections, but it has institutionalized UHPC as a solution for creating connections between PBEs. PBE is an effective Accelerated Bridge Construction (ABC) method. ABC is a FHWA EDC Round 2 (EDC-2) innovation that Pennsylvania championed innovation. It uses various methods to reduce planning and construction efforts, decrease traffic delays and potentially lower project costs. These methods help to build bridges faster and stronger and improve safety without sacrificing quality. Some other ABC methods include Quick Construction Box Culverts (box culverts constructed in two weeks or less), Self-Propelled Modular Transporters, Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS) and Slide-In Bridge Construction.
How Does It Work?
As UHPC function exceeds that normally predicted for a field-cast connection, it allows the behavior of the joined prefabricated components to surpass conventional construction. Compared to many solutions, UHPC allows for small, simple-to-construct connections that require less volume than field-cast concrete and do not require post-tensioning.
What Are The Benefits?
Using UHPC with PBEs makes construction faster and more cost effective, and produces a higher quality product. Since the bridge components are cast off-site, the roadways and bridges are closed for a shorter time, lessening the impact on the travelling public.
Innovation in Motion
One significant project where PennDOT used UHPC was I-78 in PennDOT District 5, Berks County. In 2016 and 2017, six bridges were rebuilt to increase the vertical clearance over I-78. UHPC was used to connect all the components of the PBEs together to increase strength and open the bridges and interstate to traffic more quickly.
For more information about this innovation, contact the
STIC Management Team.