Summary

Challenge: The bridge carrying the US Route 1 Bypass over Maine Route 236 was both structurally deficient and functionally obsolete due to substandard vertical clearances. MJ assisted the MaineDOT with the development of a financial grant application through the second Strategic Highway Research Program (SHRP2) to utilize Accelerated Bridge Construction (ABC) methods along with SHRP2 ABC toolkit for the replacement bridge. The federal grant application was successful and the project was awarded more than $500,000 in special funding.
Solution: MJ developed a design utilizing full-depth precast NEXT beams, supported by full-height precast abutments and precast modular gravity wall wingwalls. Due to shallow bedrock at the site, a cast-in-place footing was used, which resulted in the development of an economical and rapid detail for the footing connection to the precast abutment stems. The shallow bedrock presented a challenge for the design team since more than 100 cubic yards of rock needed to be removed in a very short timeframe, however the integrity of rock could not be accurately determined during the design. To mitigate this schedule risk, the project team developed multiple footing connection details and allowed the use of unreinforced concrete subfootings to facilitate rapid construction.

The project included the first use in New England of Carbon Fiber Composite Cable (CFCC) pre-stressing strands and dual-coated reinforcing steel for increased durability. The bridge was replaced during a single 29-day roadway closure period, which included an 11-hour accelerated bridge demolition in order to minimize the required closure time of State Route 236, which serves more than 20,000 vehicles per day