Fanny Bridge Community Revitalization Project

 

Location

Tahoe City, CA (just south of SR-89 and SR-28 intersection)

City or County Responsible for Project

Placer County

Category

Bridge: Efficient and Sustainable Bridge Maintenance, Construction and Reconstruction Projects

Description

The State Route (SR) 89 Fanny Bridge Community Revitalization Project in Tahoe City is a critical transportation improvement project. The project was envisioned and underwent initial planning as far back as the 1990s; local, State, and Federal partners have collaborated closely to deliver this project. The project seeks to improve pedestrian and bicycle mobility as well as provide improved traffic circulation, evacuation, safety, and transit connections.
The full project scope includes a new bypass segment of State Route 89 with a new bridge crossing the Truckee River downstream of Fanny Bridge along with roundabouts on the east and west ends of a new bypass that has been key to managing traffic during the Fanny Bridge closure. The Truckee River Bridge, bypass, and roundabouts were constructed in 2019. The primary element of the project is the replacement of the nearly 100-year-old Fanny Bridge with a new single-span bridge. The bridge features widened sidewalks and bike lanes on both sides as well as activated pedestrian crossing signals on both ends; these improvements will provide ADA access to businesses, a transit hub and recreational areas surrounding the project area. The existing bridge had 3 spans with piers in the river and a narrow sidewalk on only one side of the bridge and did not feature bike lanes, a distinct need in this popular cycling area. These improvements will be a significant improvement for pedestrians and cyclists. Even though the new bridge is wider, it was designed so that all improvements could be completed within the existing right-of-way without any right-of-way acquisition being needed. The existing bridge also had a permanent sewer line that serves the residents of the west shore of Lake Tahoe; the line was replaced as part of the project. Based on feedback from the public via extensive outreach efforts, the new bridge matches the appearance of the historic bridge by mimicking the existing concrete bridge rail aesthetics.
The local business community in Tahoe City also requested that the bridge not be closed to traffic for project construction until after mid-August, when the tourist season nears its end (a critical element given that the local economy is heavily tourism-dependent). Tahoe Regional Planning Agency (TRPA) regulations do not allow grading of 3 cubic yards of material after October 15. These constraints significantly restricted the work window during which Fanny Bridge could be replaced. The project team coordinated with TRPA to allow project construction to extend beyond October 15 to ensure the project could be completed in a single season (mitigating the need for a winter construction pause, which would have had tremendous impact to public traffic). It is extremely rare for infrastructure projects in the Lake Tahoe Basin to plan for and be granted work extensions beyond October 15 in advance of the project kickoff.
As stated, the project has featured extensive coordination amongst various Federal, State, and local agencies. The project complies with all NEPA, CEQA, TRPA, United States Fish and Wildlife Service, U.S. Army Corps of Engineers, and Lahontan Regional Water Quality Control Board regulations. Measures are in place to protect water quality, manage stormwater runoff, preserve native species, and limit noise and dust during construction.
To expedite construction in a safe, mindful manner the project implemented FHWA “Everyday Counts (EDC) initiatives that are proven, yet underutilized innovations that make our transportation system adaptable and safer for all. These proven innovations saved time, money and resources to ensure the bridge was built better, faster, and smarter. The EDC initiatives employed on the project included:
1. Accelerated Bridge Construction (ABC)
2. Prefabricated Bridge Elements (PBES)
PBES are bridge components constructed offsite then brought to the project location, ready to erect. With traditional bridge construction, foundations for piers and abutments must be constructed first. Pier columns and caps must be installed before beams and decks are placed. With PBES, these components can be fabricated concurrently and then shipped in as needed. In addition, traditional onsite construction exposes work crews to moving traffic and to working over water or near power lines. Using PBES shortens onsite construction time so that fewer workers need to be exposed to traffic control. It results in durable bridges that can be built faster, more safely, and with fewer traffic delays.
ABC is bridge construction that uses innovative planning, design, materials, and construction methods in a safe and cost-effective manner to reduce the onsite construction time that occurs when building new bridges or replacing and rehabilitating existing bridges.
• ABC improves:
o Site Constructability
o Total project delivery time
o Work-zone safety for the traveling public
o Quality and durability of construction
• ABC reduces:
o Traffic Impacts
o Onsite construction time
o Weather-related time delays
o Social costs to the surrounding community
o Environmental impacts
A common reason to use ABC is to reduce traffic impacts because the safety of the traveling public and the flow of the transportation network are directly impacted by onsite construction related activities. However, other common and equally viable reasons to use ABC deal with site constructability issues. Oftentimes long detours, costly use of a temporary structure, remote site locations, and limited construction periods present opportunities where the use of ABC methods can provide more practical and economical solutions to those offered if conventional construction methods were used.
The Fanny Bridge Project was innovative by constructing 8 precast bridge girders and both bridge abutments off site. To further reduce the construction duration, the existing bridge wingwalls were left in place and 16 closed piles (8 on each side of the bridge) were driven into the ground behind the existing wingwalls. The precast concrete abutments were trucked in and placed. Just a few days later the 8 precast concrete girders were delivered and placed during overnight construction. Reusing the existing wingwalls reduced the need for further instream work and reduced the duration of construction.
To demolish the existing bridge, including removal of the existing concrete bridge piers, a river diversion was installed. The contractor-designed diversion included connecting 3 long culverts to the existing Tahoe City Dam (sole outlet of Lake Tahoe) and diverting the water downstream of the existing bridge. The diversion was installed prior to the 4th of July holiday to not interfere with the local rafting operations, which are extremely dependent on revenue earned over this summer holiday. The Bureau of Reclamation (BOR) did not alter their projected dam outflows to accommodate the construction of this project. Instead, the BOR provided their weekly forecasted flows with FHWA to help the contractor design the diversion system to handle the forecasted flows. The project specifications required relocation of existing fish within the diversion area; the project team engaged anglers from a local fly fishing organization to catch and relocate the fish to either Lake Tahoe or downstream based on their size, as specified by the California Department of Fish and Wildlife.
The new bridge is a single span and thus does not have any piers in the river; this is a significant aquatic improvement compared to the existing, 3 span bridge with piers in the river. Along with the new, widened sidewalks, bike lanes, and activated pedestrian crossings, the bridge will provide safer, simpler paths of travel for kayakers, pedestrians, bicyclists and the disabled. The community is very eager for the completion of the bridge (anticipated in late December 2025) as it is a key landmark entry to their small town. The local downtown association is working with the County to schedule a large community block party on the bridge to coincide with the ribbon cutting by our Board of Supervisors’ office.
Project funding was provided from a mix of Federal and local sources, including 78.5% by the Federal Lands Access Program and 21.5% local match from Placer County, TRPA and the TCPUD (sewer line only). Placer County provided the greatest amount of local funding and is serving as the lead information and coordination source with the community, which is very keen on the success of the project. The total cost of the project is $10,687,500
Significant items include:
• Removal and replacement of 1 bridge (Fanny Bridge) – new bridge is 130.5 feet in length
• 290 Cubic Yards of Structure Excavation
• Cofferdams – Lump Sum
• Dewatering – Lump Sum
• 480 Cubic Yard of Class 5 Rip Rap
• 200 Tons of Aggregate Base
• 155 Tons of Asphalt Concrete Pavement
• 595 Linear Feet of Concrete Filled Steel Pipe Piles
• 366 Cubic Yards of Structure Concrete (air entrained)
• 75 Cubic Yards of Precast Structural Concrete (air entrained) abutments
• 100 Linear Feet of Expansion Joints
• 700 Pounds of Reinforcing Steel
• 34,200 Pounds of Epoxy Coated Reinforcing Steel
• 299 Feet of Concrete Bridge Railing
• 514 Square Yards of Concrete Overlay
• 200 Square Yards of Concrete Sidewalk
• Signing and Striping
• Snow poles
• Ped signals and new bridge lighting
Overall, the project has been a vital success for the community, which is in the midst of a beautiful rebound after suffering significantly post-COVID. We look forward to the opening of the new bridge and once again leaning over the rail to watch the peaceful river and trout below.