The health of Pennsylvania bridges is a top priority, and PennDOT continues to look for ways to increase the longevity of its more than 25,000 state-owned bridges.
Bridge Deck Link Slabs, a State Transportation Innovation Council (STIC) innovation, involves using a combination of Ultra-High Performance Concrete (UHPC) and reinforced steel to connect bridge decks and eliminate deck joints to reduce the damage and deterioration caused by water and de-icing materials leaking into the joints. The advancement of this innovation is being led by Mark Nicholson, district bridge engineer in PennDOT’s District 1, located in the northwestern part of the state.
In 2020, District 1 conducted a pilot with Bridge Deck Link Slabs on the SR1009 bridge over Lake Wilhelm in Mercer County. The 181-foot bridge has three spans and was built in 1969. In the 28-day interim period until the asphalt overlay was applied, the link slab showed no signs of cracking or debonding from the adjacent deck and following a bridge inspection in June 2022, the inspectors rated the bridge deck “excellent and the superstructure very good, Nicholson said.”
Link slabs are currently being used for a bridge on SR 2102 over Interstate 79. The project is in construction and is expected to be completed this fall, said Nicholson.
“Several other PennDOT districts have contacted me with questions on the use of link slabs and are considering them on their bridge projects,” said Nicholson. “In our district, it will become a standard practice to consider them on all bridge projects, where applicable.”
Currently, link slab installation on bridges should be funded through Transportation Improvement Program (TIP) funding. Installation costs do not typically impact bridge construction projects significantly, said Nicholson.
To further advance its usage in Pennsylvania, this innovation also received $40,000 in Federal Highway Administration (FHWA) STIC Incentive Program funding in 2021.
“These funds are being used to develop a tool that will help designers evaluate the use of link slabs on their bridge projects,” said Nicholson. “It will analyze the changes to the force effects on the bridge caused by the link slabs and determine if the effects are structurally acceptable, or if additional modifications to the structure are needed.”
For more information on STIC innovations, visit PennDOT’s STIC website.