Forrest Street Underpass at IH 35 SBML and NBML
Binkley & Barfield, Inc. redesigned the Forrest Street Bridge, which was initially designed to be one 144 ft. wide bridge which included a 24 ft. u-turn, a variable width median with a 5 ft. sidewalk, a 14’ shared bike lane, and a 12 ft. lane on both the east and westbound sides of the bridge. Due to limitations concerning the minimum vertical clearance, Binkley & Barfield, Inc. separated the eastbound U-Turn bridge from the main lane bridge, created a separate U-turn alignment, and raised the U-Turn bridge profile.
The main challenge with the Forrest Street Underpass project was a result of the minimum vertical clearance and profile. Once the U-turn bridge was separated, the engineers found that it required too much haunch, so they readjusted the profile of the Eastbound and Westbound bridge to minimize the haunch and meet minimum vertical clearance requirements at all vertical clearance points on the bridges.