Project Overview
The Blue Hill Falls Bridge reconstruction project addressed the structural deficiencies of the existing bridge while enhancing public safety and preserving neighboring archaeological sites in the historic district. Spanning over saltwater, the project required a solution that offered both durability and rapid construction capabilities. To achieve these objectives cost-efficiently, precast, prestressed concrete components were chosen for their inherent strength, resilience, and efficiency.
Starting in 2010, the contemplation of how to best replace the aging historic bridge spanning the falls captivated the attention of Blue Hill's residents. An advisory committee, in tandem with the Maine Department of Transportation, meticulously explored diverse alternative designs. Over thirty hearings and meetings ensued before Maine DOT concluded that the optimal solution involved replacing the arched structure with a precast, prestressed girder bridge. The new bridge has been elevated by four feet to accommodate rising sea levels, a choice that ensures enhanced resilience for the future. Moreover, state historic and preservation authorities endorsed the plan, assuring the conservation of nearby archaeological sites, as the roadway configuration remained unaltered.
To honor the iconic local landmark, the design team seamlessly integrated granite-stone masonry pieces from the original bridge into the new bridge design, creating a lasting tribute.
Precast Solution
The project leveraged the benefits of precast, prestressed concrete to meet its structural and construction timeline requirements.
The precast concrete bridge elements, including 16 precast concrete solid approach beams, 5 prestressed NEBT girders, and 8 precast concrete arched fascia panels, were fabricated by J.P. Carrara & Sons, Inc. off-site and then assembled rapidly on-site. This approach reduced construction time, traffic disruptions, and overall project costs while ensuring high-quality construction standards.
The use of precast, prestressed concrete beams and arched fascia panels ensured the bridge's longevity, which was particularly vital given the bridge's location over saltwater. Incorporating high-strength materials like 10,000 psi concrete, stainless steel prestressing strands, and Chromex 9100 Grade 100 rebar significantly enhanced the bridge's resistance to environmental stressors, like corrosion from saltwater. This enhances structural integrity translates to longer service life and reduced maintenance requirements, offering a sustainable infrastructure solution.
The use of accelerated bridge construction methods can result in reduced construction waste and environmental impact compared to traditional methods. Off-site fabrication of precast elements allowed for precise manufacturing, minimizing material waste and potentially pollution on-site, aligning with sustainability goals often emphasized in historic preservation efforts.
By requiring fewer maintenance interventions and exhibiting prolonged service life, precast, prestressed concrete bridges offer substantial savings in terms of labor, materials, and downtime. This makes them a prudent investment for government agencies and infrastructure owners looking to optimize lifecycle costs.
Through the integration of precast, prestressed concrete and accelerated bridge construction techniques, the Blue Hill Falls Bridge Replacement project successfully addressed structural deficiencies, enhanced public safety, and delivered a resilient infrastructure solution to the community. Leveraging the benefits of precast concrete, the project minimized construction time, traffic disruptions, and overall costs while ensuring high-quality construction standards. By incorporating durable materials, the new bridge offers enhanced resilience to environmental stressors, reduced maintenance requirements, and prolonged service life. |