Marsh Street Bridge Replacement Project

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Construction to replace the bridge built in 1909 is set to begin in May and is expected to wrap in January 2021

  • Marsh Street Bridge Replacement Project Updates

    • Monday, July 13 Project Update

    • Monday, July 6 Project Update

    • Monday, June 29 Project Update

    • Monday, June 22 Project Update

    • Monday, June 15 Project Update

    • Monday, June 8 Project Update

    • Monday, June 1 Project Update


At the turn of the 20th Century, most bridges were constructed of wood or steel. In 1909, a civil engineer named John Leonard designed a bridge for San Luis Obispo made from concrete with reinforced steel, an innovative method at the time. Today, this method is utilized to construct the majority of new and replaced road and highway bridges in California.



 The Marsh Street Bridge, located between Osos Street and Santa Rosa Street at the San Luis Obispo Creek crossing, has stood for over a hundred years; however, in 2008, a bridge inspection by Caltrans determined that the bridge was structurally deficient to the point where repair or replacement was necessary. Damage was identified that affected the structural stability of the bridge and would eventually lead to its closure.


In 2013, the City reviewed options for repairing or replacing the bridge. A complete replacement of the bridge was determined to be the best option for longevity and cost‐savings. The design of the bridge was started the same year with rigorous requirements for bridge safety, sensitivity to the adjacent businesses, and protection of the environment and wildlife surrounding the bridge. Along with replacement of the bridge, an aging and deteriorating sewer main underneath the bridge will be replaced with a more efficient line. Additionally, to highlight the historical significance of the original bridge, new lighting will be installed that will replicate the original kerosene fixtures what would be lit every evening. The new pedestrian lighting poles will be equipped with energy‐efficient LED fixtures.


Construction of the new bridge is anticipated to begin mid- May 2020. This 9‐month duration may be extended if unforeseen delays occur during the construction work. While it will be inconvenient and at times frustrating, the construction of the new bridge requires the closure of Marsh Street to vehicles and pedestrians from the bridge to the Santa Rosa Street intersection. Because Marsh Street is a main corridor heading into Downtown SLO, signage will start at the Highway 101 off‐ramp and continue along Marsh Street to alert motorists of the closure and provide a number of options to detour around the construction site. The street signals along Marsh Street will be adjusted to accommodate the detour.


Construction will not cause any business closures. 

The parking lots for Merrill Lynch, New Times, Pacific Western Bank, and Cheng Park will be accessible, as well as parking for Sunset North Carwash, The Photo Shop and True West Tattoo. Due to its proximity to the bridge, the entrance to the DaVita Dialysis Center will be closed but access to their parking lot will be temporarily from Pacific Street. 




Marsh St. Bridge Before