Replacement of Gager Hill Road Bridge No. 04426 – Over Merrick Brook, Scotland, CT

PROJECT OVERVIEW

RHS Consulting Design, LLC was retained by the Connecticut Department of Transportation (CTDOT) under the State-Federal Bridge Program to deliver final design plans, specifications, and cost estimates for the replacement of Gager Hill Road Bridge No. 04426 over Merrick Brook in Scotland, Connecticut.

The existing 33-foot span bridge, 28.5 feet wide, was in poor condition due to significant superstructure deterioration. The replacement design features adjacent precast box beams with a composite shear slab, semi-integrally connected to abutments supported on micropiles.

To improve hydraulic performance in the floodplain, the bridge span is being extended to 60.1 feet, safely conveying the 100-year flood with at least one foot of freeboard. The width is also increased by two feet to meet current CTDOT geometric standards for rural local roads.

The project scope includes roadway, drainage, and safety improvements, and the design fully complies with AASHTO LRFD Bridge Design Specifications and the CTDOT Bridge Design Manual, with load rating analysis performed using the LRFR method in AASHTOWare software. 

PROJECT DETAILS

  • Project Name Replacement of Gager Hill Road Bridge No. 04426
  • Client Connecticut Department of Transportation (CTDOT
  • Category Bridge, Engineering
  • Delivery Mode the State-Federal Bridge Program
  • Location Over Merrick Brook, Scotland, CT
  • Year Built 2025

OUR MISSION

Our mission on this project was to deliver a safe, durable, and hydraulically efficient bridge replacement that meets the long-term transportation needs of the community while fully complying with CTDOT and AASHTO design standards. RHS Consulting Design, LLC was committed to providing innovative engineering solutions that improved structural performance, enhanced roadway safety, minimized environmental impacts, and ensured reliable infrastructure resilience for future generations.

CHALLANGE

One of the primary challenges of this project was designing a replacement structure within a sensitive floodplain environment while maintaining compliance with current hydraulic, structural, and geometric standards. The project required careful coordination to address the deteriorated condition of the existing bridge, improve hydraulic capacity for the 100-year storm event, accommodate limited site constraints, and minimize impacts to the surrounding environment and local roadway operations.

Additional challenges included integrating micropile-supported abutments in varying subsurface conditions, meeting modern CTDOT and AASHTO LRFD design requirements, and ensuring the proposed structure achieved long-term durability, safety, and load-carrying performance for the traveling public.

OUR SOLUTIONS

RHS Consulting Design, LLC developed a comprehensive engineering solution that addressed both the structural deficiencies of the existing bridge and the long-term hydraulic demands of the site. By extending the bridge span to 60.1 feet and utilizing adjacent precast box beams with a composite shear slab system, the design significantly improved flood conveyance capacity while enhancing structural durability and reducing future maintenance needs. Semi-integral abutments supported on micropiles were selected to accommodate challenging subsurface conditions and provide improved foundation performance within the constrained project area. In addition, the project incorporated roadway widening, drainage upgrades, and modern safety improvements to meet current CTDOT and AASHTO standards, ensuring a safe, resilient, and cost-effective transportation solution for the community.

04426 Gager Hill