Learnings from the Field Implementation of a Novel Ultra-High Performance Concrete Beam End Repair on a Corroded Steel Girder Bridge in Connecticut

Corrosion at steel beam ends is one of the most pressing challenges in the maintenance of aging bridges. To tackle this challenge, the Connecticut Department of Transportation (DOT) has partnered with the University of Connecticut to develop a repair method that benefits from the superior mechanical and durability characteristics of ultra-high performance concrete (UHPC) material. The repair involves welding shear studs to the intact portions of the web and encasing the beam end with UHPC. This provides an alternate load path for bearing forces that bypasses the corroded regions of the beam. The structural viability of the repair has been extensively proven through small- and full-scale experiments and comprehensive finite element simulations. Connecticut DOT implemented the repair for the first time in the field on a heavily trafficked four-span bridge in 2019. The UHPC beam end repair was chosen because of the access constraints and geometric complexities of the bridge that limited the viable repair options. Four of the repaired beam ends were fully instrumented to collect data on the performance of the repaired locations before casting, during curing, and for approximately 6 months following the application of the repair. This paper provides an overview of the successful repair implementation and presents the lessons learned during construction. Select data from the monitored beam ends are presented. It is expected that this information will provide engineers with a better understanding of the repair implementation process, and thus provide an additional repair option for states to enhance the safety of aging steel bridges.

High Load Jacking Frames for Pin and Hanger Replacement at the Robert Moses Causeway

An innovative design of jacking frames was developed for pin and hanger replacement in Robert Moses Causeway (RMC) bridge in Suffolk County, New York. The robust and efficient design of the jacking frames results in a system with improved safety, performance, constructability, and economy. A fully integrated approach for design, fabrication, and construction was employed for higher quality and efficiency. A detailed and precise 3D model was created and directly used for finite element (FE) modeling, producing contract and shop drawings, and designing of temporary work platforms. This paper provides an overview of the integrated design approach and system design, and documents the computational study for this system (global analysis, stress analysis, and large-displacement stability analysis). There are many aging steel bridges in the U.S. and abroad that have similar pin and hanger systems, and jacking frames will be needed to replace those pins and hangers when they exhaust their useful service life. The concepts and details of the jacking frames can easily be emulated by engineers for developing similar safe and robust systems for suspended truss spans and other applicable bridge structures.