Binghamton, NY
Scope/Solutions
A buried precast concrete arch was constructed to carry a 60 ft span of I-81 over Chenango Street in Binghamton, New York. After five years in service, the arch experienced concrete cracking and 12 in. of deflection at the crown. New York State Department of Transportation (NYSDOT) contacted SGH to assess the structure and eventually design repairs that were executed with uninterrupted access to the interstate above.
Our investigation included site surveys, borescope surveys at drilled openings, and nondestructive testing of the concrete structure, including ground penetrating radar, impact echo, spectral analysis of surface waves, and ultrasonic pulse echo performed in collaboration with Olson Engineering. We also performed petrographic analysis on extracted cores that helped identify a high potential for concrete creep.
SGH developed a three-dimensional finite element model to analyze soil-structure interaction and the nonlinear effects of concrete creep. Our results successfully replicated the distressed state and helped us demonstrate that construction staging significantly impacted its structural performance. We used the model to predict the deflection due to creep and the effects of thermal loads on bridge deflections over time and corroborated the results with field measurements.
We checked the design and calculated a load rating that substantiated the need for repairs. SGH designed a concrete liner retrofit installed inside the existing arch to achieve the intended seventy-five-year service life. We provided support during construction, including consulting on the challenging overhead concrete placement.
SGH also provided NYSDOT with monitoring criteria to help them verify adequate structural performance in the future.
Project Summary
