ODOT Stark-77 Bridge Replacement and Rehabilitation
FIRST-IN-STATE PILING TECHNIQUE USED ON A COMPLEX HIGHWAY BRIDGE REPLACEMENT AND REHABILITATION IN STARK COUNTY, OHIO.
What We Did
Gannett Fleming was originally contracted to provide engineering services to the Ohio Department of Transportation (ODOT) District 4, for the inspection and rehabilitation of two structures: I-77 Bridge 0912 over local streets; and I-77 Bridge 0937 over the West Branch of Nimishillen Creek, in Canton, Ohio.
The existing bridge 0912 was a seven-span, 630-foot-long, continuous steel deck-girder bridge with a non-composite deck, including an integral steel pier cap over 15th Street; it is skewed 30 degrees. The existing bridge 0937 was a two-span, 330-foot-long, continuous steel deck-girder bridge with a non-composite deck, supported by a wall-type pier and counterfort wall-type abutments with a maximum height of 50 feet at the forward end; it is skewed 65 degrees. ODOT’s requirement to maintain two lanes of traffic throughout construction was a complicating factor for the project team as the skew and adjacent structures impacted available lane width.
One of the initial tasks of the project was to inspect the bridges to identify structural issues that needed to be repaired. Our inspectors discovered that the ends of the steel girders for I-77 Bridge 0937 and the Ramp D bridge (which share the same 50-foot-tall forward abutment) were bearing against the backwall. Discussions with ODOT revealed that the girder ends were trimmed at least once in the past to provide room for expansion. Also of note were out-of-plumb piers on the adjacent curved Ramp D bridge (added to the project since it shared a substructure) and water flowing from the 0937 pier, which was above the stream level.
During an intense geotechnical investigation, a unique and difficult hydrogeologic condition became apparent, making the shared 50-foot-tall, counterfort wall-type abutment move via translational failure of the pile foundation. The entire site sits atop two buried aquifers, with the lower aquifer being highly charged and flowing through a very porous substrate. The two aquifers were connected through the aquitard via the piles driven on the interchange structure construction in the late 1960s, making the water migration between them more acute than the original condition. After extensive analysis, coordination, monitoring, and testing, the design was progressed with two bridge replacements and three rehabilitations:
- Replacement of 0937 (new 477-foot-long, two-span, 67-degree skew) and curved Ramp D (new 587-foot-radius-curve, 315-foot-long, two-span, variable skew with a maximum of 59 degrees).
- One major rehabilitation, 0912 (627-foot-long, seven-span, 30-degree skew, made semi-integral and composite while also removing the end-span hinges).
- Two minor modifications, Ramp G and 0950 over Navarre Road.
The plans required extensive planning and detailing of construction phasing to mitigate risks of deconstructing the existing superstructures, which acted as horizontal struts against the existing abutment movement. The new abutments use geosynthetic reinforced soil (GRS) and cellular lightweight concrete fill behind abutment backwalls (semi-integral and traditional) to alleviate horizontal pressures on the superstructure and substructures. A 72-inch-diameter sanitary sewer relocation was needed to clear the site for construction, which required extensive de-watering and underground transition structures.
Ultimately the deep foundations, which proved to be the most problematic existing condition and element to design, consisted of a combination of 42-inch and 48-inch friction drilled shafts. The roughened surface of an uncased drilled shaft was beneficial in that it slowed the upward migration of water and loss of fines. During construction, the difficult subsurface was dealt with via the original plans and the larger 0936 structure was re-designed during construction to use augered cast-in-place (ACIP) piles; though they are prevalent in vertical construction, it was a first-time use for an ODOT bridge foundation.
ACIP piles have been used in Europe since the 1960s and extensively in the U.S. since the 1980s. Their use has been prevalent in vertical structures, while bridge and transportation structures have been slow to adopt, with AASHTO not addressing their design.
The new, two-span 0936 bridge provided the opportunity to leverage the constructability benefits of ACIP foundations for the first time for ODOT.
The new, two-span 0936 bridge provided the opportunity to leverage the constructability benefits of ACIP foundations for the first time for ODOT. Through this project, our team:
- Collected data to help validate design methods.
- Implemented an integrity testing program.
- Compared various methods of load testing the in-situ performance of such an array.
The 217-foot-long pier footing was supported by 176 ACIP piles in four rows that required battered, low-headroom, phased installations, and the charged aquifer challenges . Being a new foundation type for ODOT, the project had a rigorous installation plan that employed:
- Demonstration piles.
- Mix designs.
- Full-length cage installations.
- Thermal integrity testing.
- Static testing.
- Dynamic testing.
Data gathered from this large-scale use of ACIP piles for a large bridge foundation can help advance their acceptance as a viable bridge foundation in AASHTO publications and provide another beneficial solution for highway and bridge owners.
- First use of ACIP piles in Ohio.
- Replacement of two interstate bridges.
- Rehabilitation of three interstate bridges.
- Maintained two lanes of traffic throughout construction.
Ohio Department of Transportation
Engineering Services, Foundation Construction Observation