Aurora Drive Noyes Slough Bridge Replacement Project No. 0629001/NFHWY00124 & NRMBS00688

Figure 1 Noyes Slough Bridge in winter

We are working to replace the existing bridge (#0209) over the Noyes Slough located on Aurora Drive. Originally constructed in the early 1960s, the existing two-span 103 feet long and 36 feet wide bridge has multiple issues that make it undesirable to rehabilitate as opposed to replace. The bridge deck is in poor condition, and the center of the deck is supported by a pier that catches large amounts of floating debris and causes scour hazard. The sidewalk across the bridge is only 3 feet wide (2.5 feet wide at each end of the bridge) which is not ADA compliant. The current bridge profile also poses a safety issue due to inadequate sight distance for drivers using adjacent driveways and side streets.

Aurora Bridge Design Animated Flyover from Alaska DOT&PF on Vimeo.

The purpose of this project is to provide:

• A 100-foot-long single-span prestressed concrete girder replacement bridge with pile supported abutments protected by sheet piling.
• 5-foot-wide shared use sidewalks
• 2-foot shoulders (edge of lane to face of curb, consisting of 6 inches of asphalt and 18 inches of concrete gutter)
• 2-foot shift to the west, essentially keeping the upstream edge of the bridge near the existing upstream edge since the new bridge is wider than the existing.

Figure 2. Existing Noyes Slough Bridge deck is supported by a center pier that catches large amounts of floating logs/debris and cause a scour hazard.

Figure 3. Existing Noyes Slough Bridge poses safety issue due to inadequate sight distance for drivers at adjacent driveways and side streets.

Figure 4. 3-ft wide sidewalk on the existing Noyes Slough Bridge is ADA noncompliant.

Figure 5. Project Limits

Work on this project includes:

• Demolishing the existing bridge
• Constructing new bridge
• Installing new water main relocation across the slough
• Replacing waterline under Aurora Drive
• Slip-lining existing sewer line across the slough
• Installing curb and gutter, ADA-compliant sidewalks and curb ramps, and other ADA improvements
• Repaving and restriping the road surface

Construction on this project began in March 2023, and will complete before the end of June 2024. The Aurora Bridge project is still waiting on the seven concrete girders that span the slough due to delays from the Anchorage manufacturer. The girders are expected to be delivered in October, the late arrival means that we will not be able to complete construction in 2023.

While it is a serious inconvenience, Alaska DOT&PF wants to do the job right the first time and will finish the bridge by the end of June 2024.

This project is being constructed in cooperation with the Alaska Division of the Federal Highway Administration and Design Consultant RESPEC Company, LLC., and Contractor HC Contractors, LLC.