SLO’s Morretti Canyon Road Bridge to Close for Repairs from October 21 to 23

The Morretti Canyon Road bridge will be closed to traffic for some hours from October 21 to October 23, 2025, the County of San Luis Obispo Department of Public Works announced on its website.

Located about 1.5 miles east of Orcutt Road, the Morretti Canyon Road bridge will be closed to the public daily from 8:30 a.m. to 5:30 p.m. each day. The bridge will stay open outside of those hours, the county’s Department of Public Works added.

The department released a map to help residents know which stretch of the road will remain closed during the proposed repairs.

Repairs to Address Two Issues

The repair work will address two issues. First, a timber component that failed inspection will be replaced. Second, the weight restriction for the bridge will be removed. The current weight restriction limits the capacity of heavy trucks that can use the bridge.

Once the repairs are complete and the timber component is replaced, the weight restriction will be lifted.

The bridge will remain closed to both vehicles as well as pedestrians during the proposed repairs. While the closure might cause temporary inconvenience, the work is necessary to ensure safe access for residents and emergency services, county officials added.

Why is Regular Upkeep and Maintenance Necessary for Timber Bridges?

Timber bridges are common throughout California, valued for their strength and flexibility in seismic zones. However, they require regular maintenance to resist decay and weather damage, which is one reason the San Luis Obispo County is undertaking the upcoming repairs.

Timber bridges are strong, cost-effective, and durable in active seismic zones, such as California. Such bridges have a high strength-to-weight ratio. Timber bridges also have a natural flexibility, which helps them sway and stay resilient during seismic activity.

However, timber bridges need regular upkeep and treatment. This helps them stay resistant to decay, moisture, and damage by insects. While timber is eco-friendly, biodegradable, and uses less energy, it can be a fire risk. It also tends to have a shorter lifespan.

Timber also needs careful maintenance to prevent shrinking, swelling, and warping. If not treated properly, it can lose its shock resistance. This makes timber bridges more vulnerable to damage from vehicle crashes. 

Many timber bridges across California date back to the 19th and early 20th centuries. This includes the Goat Canyon, the world’s longest wooden railroad bridge. Located in San Diego, the massive trestle was made of Redwood timber and was built in 1933.