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Source : TxDOT
April 8, 2021
Author : Patty Rodriguez
The Texas Department of Transportation recently rehabilitated one of the most important bridges in the country with the innovative technique. The Sidney Sherman Bridge, strategically located near the Port of Houston, sees a massive amount of truck traffic and is consistently ranked the highest in the nation in terms of tonnage.
According to a press release from the Federal Highway Administration, “TxDOT had identified severe corrosion in critical zones at the ends of the steel girders. The complex connections trapped water and debris that resulted in continuous and severe corrosion over time. By the time this was identified, the situation had become critical and immediate action was required.”
TxDOT began considering replacing the bridge all together, but it would take 15-20 years for construction to start. “Conventional repair methods would have been difficult and costly to implement due to an unacceptable length of traffic closures on the bridge,” according to the press release.
So they tried the ultra-high performance concrete (UHPC). “The UHPC beam end repair technique, which involves removing corroded steel, installing headed shear connectors, and casting UHPC, provided an alternative solution that allowed the bridge to be repaired safely and with a minimum disruption to service. TxDOT selected UHPC for the project due to its high flowability, high strength, high ductility, and low permeability.”
When the project was completed, TxDOT assessed the method to be highly effective and having “great potential for further application in the rehabilitation of aging infrastructure across the nation.”
The below video, released by the University of Connecticut’s Civil and Environmental Engineering department, demonstrates in detail how it all works. Connecticut recently tried out UHPC on 45 beams on a 55-year-old bridge over I-91 in Connecticut which was selected because of its complexity.
Ultra-high performance concrete consists of “fiber-reinforced, cementitious composite material with mechanical and durability properties that far exceed those of conventional concrete materials” according to the Federal Highway Administration.
UHPC can be used to replace conventional concrete, repair mortars, and even structural steel in some cases and is “ long lasting and resilient, requiring less maintenance and fewer follow-up repairs than conventional methods.”
UHPC applications include “bridge deck overlays, girder end repairs, expansion joint repairs, PBE construction joint repairs, and column or pile jacketing. Some applications, such as bridge deck overlays and replacing expansion joints with UHPC link slabs, can extend the service life of bridges well beyond that of traditional repair strategies and are more cost-efficient than bridge replacement.”
The new technique was tried in 11 states in 2020, including Iowa, Illinois, Alabama, Florida, West Virginia, Pennsylvania, New York, Connecticut, Rhode Island, Maryland and New Jersey.
Meanwhile, at the International Bridge Conference in June, the UHPC team will give two workshops on the technique.
Category : Contractor Trades Department of Transportation Efficiency-Improving Technology Federal Government Investment in Infrastructure Modular & Prefabricated Construction Tech Bridges Public Works