Union Chapel and I-69 | Interchange Modification
FORT WAYNE, IN—As one of the first roundabout interchanges designed for Indiana, the project is located along I-69 at Union Chapel Road in metropolitan. After investigating multiple options, the selected alternative involved the development of construction plans for a compact diamond interchange with dual lane roundabouts at the ramp termini. All of the approach legs have dual lanes. In order to reduce adverse impacts to the adjacent property owners and golf course, it was necessary to construct both retaining and noise walls as a part of the project.
The selection of a compact diamond interchange with dual lane roundabouts at the ramp termini presents severalchallenges for the geometric design. The curved geometry of the “dogbone” roundabout required close attention to horizontal curvature and vertical profiles to ensure the finished interchange provides a smooth driving experience. Detailed calculations and spot elevation diagrams ensure the connections to the ramps and Union Chapel Road fit perfectly with the circular roundabouts. Additionally, it is necessary to ensure the profiles did not exceed 2% cross slope in the crosswalks to be ADA compliant.
- Two-span, prestress concrete bulb tee beam structure approximately 180 feet long.
- Utilized "dog bone" geometrics.
- Width varies from 100 feet to 118 feet, which required the bulb-tee spacing to varry accordingly.
- Bridge is supported by integral concrete end bents.
- Drainage uses a combination of roadside ditches and storm sewers.